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• A Taxonomy of Numerical Methods v1

  - by JoshReuben

  Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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• C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

  - by James Michael Hare

  Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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• Tips on Migrating from AquaLogic .NET Accelerator to WebCenter WSRP Producer for .NET

  - by user647124

  This year I embarked on a journey to migrate a group of ASP.NET web applications developed to integrate with WebLogic Portal 9.2 via the AquaLogic® Interaction .NET Application Accelerator 1.0 to instead use the Oracle WebCenter WSRP Producer for .NET and integrated with WebLogic Portal 10.3.4. It has been a very winding path and this blog entry is intended to share both the lessons learned and relevant approaches that led to those learnings. Like most journeys of discovery, it was not a direct path, and there are notes to let you know when it is practical to skip a section if you are in a hurry to get from here to there. For the Curious From the perspective of necessity, this section would be better at the end. If it were there, though, it would probably be read by far fewer people, including those that are actually interested in these types of sections. Those in a hurry may skip past and be none the worst for it in dealing with the hands-on bits of performing a migration from .NET Accelerator to WSRP Producer. For others who want to talk about why they did what they did after they did it, or just want to know for themselves, enjoy. A Brief (and edited) History of the WSRP for .NET Technologies (as Relevant to the this Post) Note: This section is for those who are curious about why the migration path is not as simple as many other Oracle technologies. You can skip this section in its entirety and still be just as competent in performing a migration as if you had read it. The currently deployed architecture that was to be migrated and upgraded achieved initial integration between .NET and J2EE over the WSRP protocol through the use of The AquaLogic Interaction .NET Application Accelerator. The .NET Accelerator allowed the applications that were written in ASP.NET and deployed on a Microsoft Internet Information Server (IIS) to interact with a WebLogic Portal application deployed on a WebLogic (J2EE application) Server (both version 9.2, the state of the art at the time of its creation). At the time this architectural decision for the application was made, both the AquaLogic and WebLogic brands were owned by BEA Systems. The AquaLogic brand included products acquired by BEA through the acquisition of Plumtree, whose flagship product was a portal platform available in both J2EE and .NET versions. As part of this dual technology support an adaptor was created to facilitate the use of WSRP as a communication protocol where customers wished to integrate components from both versions of the Plumtree portal. The adapter evolved over several product generations to include a broad array of both standard and proprietary WSRP integration capabilities. Later, BEA Systems was acquired by Oracle. Over the course of several years Oracle has acquired a large number of portal applications and has taken the strategic direction to migrate users of these myriad (and formerly competitive) products to the Oracle WebCenter technology stack. As part of Oracle’s strategic technology roadmap, older portal products are being schedule for end of life, including the portal products that were part of the BEA acquisition. The .NET Accelerator has been modified over a very long period of time with features driven by users of that product and developed under three different vendors (each a direct competitor in the same solution space prior to merger). The Oracle WebCenter WSRP Producer for .NET was introduced much more recently with the key objective to specifically address the needs of the WebCenter customers developing solutions accessible through both J2EE and .NET platforms utilizing the WSRP specifications. The Oracle Product Development Team also provides these insights on the drivers for developing the WSRP Producer: ***************************************** Support for ASP.NET AJAX. Controls using the ASP.NET AJAX script manager do not function properly in the Application Accelerator for .NET. Support 2 way SSL in WLP. This was not possible with the proxy/bridge set up in the existing Application Accelerator for .NET. Allow developers to code portlets (Web Parts) using the .NET framework rather than a proprietary framework. Developers had to use the Application Accelerator for .NET plug-ins to Visual Studio to manage preferences and profile data. This is now replaced with the .NET Framework Personalization (for preferences) and Profile providers. The WSRP Producer for .NET was created as a new way of developing .NET portlets. It was never designed to be an upgrade path for the Application Accelerator for .NET. .NET developers would create new .NET portlets with the WSRP Producer for .NET and leave any existing .NET portlets running in the Application Accelerator for .NET. ***************************************** The advantage to creating a new solution for WSRP is a product that is far easier for Oracle to maintain and support which in turn improves quality, reliability and maintainability for their customers. No changes to J2EE applications consuming the WSRP portlets previously rendered by the.NET Accelerator is required to migrate from the Aqualogic WSRP solution. For some customers using the .NET Accelerator the challenge is adapting their current .NET applications to work with the WSRP Producer (or any other WSRP adapter as they are proprietary by nature). Part of this adaptation is the need to deploy the .NET applications as a child to the WSRP producer web application as root. Differences between .NET Accelerator and WSRP Producer Note: This section is for those who are curious about why the migration is not as pluggable as something such as changing security providers in WebLogic Server. You can skip this section in its entirety and still be just as competent in performing a migration as if you had read it. The basic terminology used to describe the participating applications in a WSRP environment are the same when applied to either the .NET Accelerator or the WSRP Producer: Producer and Consumer. In both cases the .NET application serves as what is referred to as a WSRP environment as the Producer. The difference lies in how the two adapters create the WSRP translation of the .NET application. The .NET Accelerator, as the name implies, is meant to serve as a quick way of adding WSRP capability to a .NET application. As such, at a high level, the .NET Accelerator behaves as a proxy for requests between the .NET application and the WSRP Consumer. A WSRP request is sent from the consumer to the .NET Accelerator, the.NET Accelerator transforms this request into an ASP.NET request, receives the response, then transforms the response into a WSRP response. The .NET Accelerator is deployed as a stand-alone application on IIS. The WSRP Producer is deployed as a parent application on IIS and all ASP.NET modules that will be made available over WSRP are deployed as children of the WSRP Producer application. In this manner, the WSRP Producer acts more as a Request Filter than a proxy in the WSRP transactions between Producer and Consumer. Highly Recommended Enabling Logging Note: You can skip this section now, but you will most likely want to come back to it later, so why not just read it now? Logging is very helpful in tracking down the causes of any anomalies during testing of migrated portlets. To enable the WSRP Producer logging, update the Application_Start method in the Global.asax.cs for your .NET application by adding log4net.Config.XmlConfigurator.Configure(); IIS logs will usually (in a standard configuration) be in a sub folder under C:\WINDOWS\system32\LogFiles\W3SVC. WSRP Producer logs will be found at C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdefault\Logs\WSRPProducer.log InputTrace.webinfo and OutputTrace.webinfo are located under C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdefault and can be useful in debugging issues related to markup transformations. Things You Must Do Merge Web.Config Note: If you have been skipping all the sections that you can, now is the time to stop and pay attention J Because the existing .NET application will become a sub-application to the WSRP Producer, you will want to merge required settings from the existing Web.Config to the one in the WSRP Producer. Use the WSRP Producer Master Page The Master Page installed for the WSRP Producer provides common, hiddenform fields and JavaScripts to facilitate portlet instance management and display configuration when the child page is being rendered over WSRP. You add the Master Page by including it in the <@ Page declaration with MasterPageFile="~/portlets/Resources/MasterPages/WSRP.Master" . You then replace: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" > <HTML> <HEAD> With <asp:Content ID="ContentHead1" ContentPlaceHolderID="wsrphead" Runat="Server"> And </HEAD> <body> <form id="theForm" method="post" runat="server"> With </asp:Content> <asp:Content ID="ContentBody1" ContentPlaceHolderID="Main" Runat="Server"> And finally </form> </body> </HTML> With </asp:Content> In the event you already use Master Pages, adapt your existing Master Pages to be sub masters. See Nested ASP.NET Master Pages for a detailed reference of how to do this. It Happened to Me, It Might Happen to You…Or Not Watch for Use of Session or Request in OnInit In the event the .NET application being modified has pages developed to assume the user has been authenticated in an earlier page request there may be direct or indirect references in the OnInit method to request or session objects that may not have been created yet. This will vary from application to application, so the recommended approach is to test first. If there is an issue with a page running as a WSRP portlet then check for potential references in the OnInit method (including references by methods called within OnInit) to session or request objects. If there are, the simplest solution is to create a new method and then call that method once the necessary object(s) is fully available. I find doing this at the start of the Page_Load method to be the simplest solution. Case Sensitivity .NET languages are not case sensitive, but Java is. This means it is possible to have many variations of SRC= and src= or .JPG and .jpg. The preferred solution is to make these mark up instances all lower case in your .NET application. This will allow the default Rewriter rules in wsrp-producer.xml to work as is. If this is not practical, then make duplicates of any rules where an issue is occurring due to upper or mixed case usage in the .NET application markup and match the case in use with the duplicate rule. For example: <RewriterRule> <LookFor>(href=\"([^\"]+)</LookFor> <ChangeToAbsolute>true</ChangeToAbsolute> <ApplyTo>.axd,.css</ApplyTo> <MakeResource>true</MakeResource> </RewriterRule> May need to be duplicated as: <RewriterRule> <LookFor>(HREF=\"([^\"]+)</LookFor> <ChangeToAbsolute>true</ChangeToAbsolute> <ApplyTo>.axd,.css</ApplyTo> <MakeResource>true</MakeResource> </RewriterRule> While it is possible to write a regular expression that will handle mixed case usage, it would be long and strenous to test and maintain, so the recommendation is to use duplicate rules. Is it Still Relative? Some .NET applications base relative paths with a fixed root location. With the introduction of the WSRP Producer, the root has moved up one level. References to ~/ will need to be updated to ~/portlets and many ../ paths will need another ../ in front. I Can See You But I Can’t Find You This issue was first discovered while debugging modules with code that referenced the form on a page from the code-behind by name and/or id. The initial error presented itself as run-time error that was difficult to interpret over WSRP but seemed clear when run as straight ASP.NET as it indicated that the object with the form name did not exist. Since the form name was no longer valid after implementing the WSRP Master Page, the likely fix seemed to simply update the references in the code. However, as the WSRP Master Page is external to the code, a compile time error resulted: Error      155         The name 'form1' does not exist in the current context                C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdefault\portlets\legacywebsite\module\Screens \Reporting.aspx.cs                51           52           legacywebsite.module Much hair-pulling research later it was discovered that it was the use of the FindControl method causing the issue. FindControl doesn’t work quite as expected once a Master Page has been introduced as the controls become embedded in controls, require a recursion to find them that is not part of the FindControl method. In code where the page form is referenced by name, there are two steps to the solution. First, the form needs to be referenced in code generically with Page.Form. For example, this: ToggleControl ctrl = new ToggleControl(frmManualEntry, FunctionLibrary.ParseArrayLst(userObj.Roles)); Becomes this: ToggleControl ctrl = new ToggleControl(Page.Form, FunctionLibrary.ParseArrayLst(userObj.Roles)); Generally the form id is referenced in most ASP.NET applications as a path to a control on the form. To reach the control once a MasterPage has been added requires an additional method to recurse through the controls collections within the form and find the control ID. The following method (found at Rick Strahl's Web Log) corrects this very nicely: public static Control FindControlRecursive(Control Root, string Id) { if (Root.ID == Id) return Root; foreach (Control Ctl in Root.Controls) { Control FoundCtl = FindControlRecursive(Ctl, Id); if (FoundCtl != null) return FoundCtl; } return null; } Where the form name is not referenced, simply using the FindControlRecursive method in place of FindControl will be all that is necessary. Following the second part of the example referenced earlier, the method called with Page.Form changes its value extraction code block from this: Label lblErrMsg = (Label)frmRef.FindControl("lblBRMsg" To this: Label lblErrMsg = (Label) FunctionLibrary.FindControlRecursive(frmRef, "lblBRMsg" The Master That Won’t Step Aside In most migrations it is preferable to make as few changes as possible. In one case I ran across an existing Master Page that would not function as a sub-Master Page. While it would probably have been educational to trace down why, the expedient process of updating it to take the place of the WSRP Master Page is the route I took. The changes are highlighted below: … <asp:ContentPlaceHolder ID="wsrphead" runat="server"></asp:ContentPlaceHolder> </head> <body leftMargin="0" topMargin="0"> <form id="TheForm" runat="server"> <input type="hidden" name="key" id="key" value="" /> <input type="hidden" name="formactionurl" id="formactionurl" value="" /> <input type="hidden" name="handle" id="handle" value="" /> <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true" > </asp:ScriptManager> This approach did not work for all existing Master Pages, but fortunately all of the other existing Master Pages I have run across worked fine as a sub-Master to the WSRP Master Page. Moving On In Enterprise Portals, even after you get everything working, the work is not finished. Next you need to get it where everyone will work with it. Migration Planning Providing that the server where IIS is running is adequately sized, it is possible to run both the .NET Accelerator and the WSRP Producer on the same server during the upgrade process. The upgrade can be performed incrementally, i.e., one portlet at a time, if server administration processes support it. Those processes would include the ability to manage a second producer in the consuming portal and to change over individual portlet instances from one provider to the other. If processes or requirements demand that all portlets be cut over at the same time, it needs to be determined if this cut over should include a new producer, updating all of the portlets in the consumer, or if the WSRP Producer portlet configuration must maintain the naming conventions used by the .NET Accelerator and simply change the WSRP end point configured in the consumer. In some enterprises it may even be necessary to maintain the same WSDL end point, at which point the IIS configuration will be where the updates occur. The downside to such a requirement is that it makes rolling back very difficult, should the need arise. Location, Location, Location Not everyone wants the web application to have the descriptively obvious wsrpdefault location, or needs to create a second WSRP site on the same server. The instructions below are from the product team and, while targeted towards making a second site, will work for creating a site with a different name and then remove the old site. You can also change just the name in IIS. Manually Creating a WSRP Producer Site Instructions (NOTE: all executables used are the same ones used by the installer and “wsrpdev” will be the name of the new instance): 1. Copy C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdefault to C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdev. 2. Bring up a command window as an administrator 3. Run C:\Oracle\Middleware\WSRPProducerForDotNet\uninstall_resources\IISAppAccelSiteCreator.exe install WSRPProducers wsrpdev "C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdev" 8678 2.0.50727 4. Run C:\Oracle\Middleware\WSRPProducerForDotNet\uninstall_resources\PermManage.exe add FileSystem C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdev "NETWORK SERVICE" 3 1 5. Run C:\Oracle\Middleware\WSRPProducerForDotNet\uninstall_resources\PermManage.exe add FileSystem C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdev EVERYONE 1 1 6. Open up C:\Oracle\Middleware\WSRPProducerForDotNet\wsdl\1.0\WSRPService.wsdl and replace wsrpdefault with wsrpdev 7. Open up C:\Oracle\Middleware\WSRPProducerForDotNet\wsdl\2.0\WSRPService.wsdl and replace wsrpdefault with wsrpdev Tests: 1. Bring up a browser on the host itself and go to http://localhost:8678/wsrpdev/wsdl/1.0/WSRPService.wsdl and make sure that the URLs in the XML returned include the wsrpdev changes you made in step 6. 2. Bring up a browser on the host itself and see if the default sample comes up: http://localhost:8678/wsrpdev/portlets/ASPNET_AJAX_sample/default.aspx 3. Register the producer in WLP and test the portlet. Changing the Port used by WSRP Producer The pre-configured port for the WSRP Producer is 8678. You can change this port by updating both the IIS configuration and C:\Oracle\Middleware\WSRPProducerForDotNet\[WSRP_APP_NAME]\wsdl\1.0\WSRPService.wsdl. Do You Need to Migrate? Oracle Premier Support ended in November of 2010 for AquaLogic Interaction .NET Application Accelerator 1.x and Extended Support ends in November 2012 (see http://www.oracle.com/us/support/lifetime-support/lifetime-support-software-342730.html for other related dates). This means that integration with products released after November of 2010 is not supported. If having such support is the policy within your enterprise, you do indeed need to migrate. If changes in your enterprise cause your current solution with the .NET Accelerator to no longer function properly, you may need to migrate. Migration is a choice, and if the goals of your enterprise are to take full advantage of newer technologies then migration is certainly one activity you should be planning for.

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• An Honest look at SharePoint Web Services

  - by juanlarios

  INTRODUCTION If you are a SharePoint developer you know that there are two basic ways to develop against SharePoint. 1) The object Model 2) Web services. SharePoint object model has the advantage of being quite rich. Anything you can do through the SharePoint UI as an administrator or end user, you can do through the object model. In fact everything that is done through the UI is done through the object model behind the scenes. The major disadvantage to getting at SharePoint this way is that the code needs to run on the server. This means that all web parts, event receivers, features, etc… all of this is code that is deployed to the server. The second way to get to SharePoint is through the built in web services. There are many articles on how to manipulate web services, how to authenticate to them and interact with them. The basic idea is that a remote application or process can contact SharePoint through a web service. Lots has been written about how great these web services are. This article is written to document the limitations, some of the issues and frustrations with working with SharePoint built in web services. Ultimately, for the tasks I was given to , SharePoint built in web services did not suffice. My evaluation of SharePoint built in services was compared against creating my own WCF Services to do what I needed. The current project I'm working on right now involved several "integration points". A remote application, installed on a separate server was to contact SharePoint and perform an task or operation. So I decided to start up Visual Studio and built a DLL and basically have 2 layers of logic. An integration layer and a data layer. A good friend of mine pointed me to SOLID principles and referred me to some videos and tutorials about it. I decided to implement the methodology (although a lot of the principles are common sense and I already incorporated in my coding practices). I was to deliver this dll to the application team and they would simply call the methods exposed by this dll and voila! it would do some task or operation in SharePoint. SOLUTION My integration layer implemented an interface that defined some of the basic integration tasks that I was to put together. My data layer was about the same, it implemented an interface with some of the tasks that I was going to develop. This gave me the opportunity to develop different data layers, ultimately different ways to get at SharePoint if I needed to. This is a classic SOLID principle. In this case it proved to be quite helpful because I wrote one data layer completely implementing SharePoint built in Web Services and another implementing my own WCF Service that I wrote. I should mention there is another layer underneath the data layer. In referencing SharePoint or WCF services in my visual studio project I created a class for every web service call. So for example, if I used List.asx. I created a class called "DocumentRetreival" this class would do the grunt work to connect to the correct URL, It would perform the basic operation of contacting the service and so on. If I used a view.asmx, I implemented a class called "ViewRetrieval" with the same idea as the last class but it would now interact with all he operations in view.asmx. This gave my data layer the ability to perform multiple calls without really worrying about some of the grunt work each class performs. This again, is a classic SOLID principle. So, in order to compare them side by side we can look at both data layers and with is involved in each. Lets take a look at the "Create Project" task or operation. The integration point is described as , "dll is to provide a way to create a project in SharePoint". Projects , in this case are basically document libraries. I am to implement a way in which a remote application can create a document library in SharePoint. Easy enough right? Use the list.asmx Web service in SharePoint. So here we go! Lets take a look at the code. I added the List.asmx web service reference to my project and this is the class that contacts it:  class DocumentRetrieval     {         private ListsSoapClient _service;      d   private bool _impersonation;         public DocumentRetrieval(bool impersonation, string endpt)         {             _service = new ListsSoapClient();             this.SetEndPoint(string.Format("{0}/{1}", endpt, ConfigurationManager.AppSettings["List"]));             _impersonation = impersonation;             if (_impersonation)             {                 _service.ClientCredentials.Windows.ClientCredential.Password = ConfigurationManager.AppSettings["password"];                 _service.ClientCredentials.Windows.ClientCredential.UserName = ConfigurationManager.AppSettings["username"];                 _service.ClientCredentials.Windows.AllowedImpersonationLevel =                     System.Security.Principal.TokenImpersonationLevel.Impersonation;             }     private void SetEndPoint(string p)          {             _service.Endpoint.Address = new EndpointAddress(p);          }          /// <summary>         /// Creates a document library with specific name and templateID         /// </summary>         /// <param name="listName">New list name</param>         /// <param name="templateID">Template ID</param>         /// <returns></returns>         public XmlElement CreateLibrary(string listName, int templateID, ref ExceptionContract exContract)         {             XmlDocument sample = new XmlDocument();             XmlElement viewCol = sample.CreateElement("Empty");             try             {                 _service.Open();                 viewCol = _service.AddList(listName, "", templateID);             }             catch (Exception ex)             {                 exContract = new ExceptionContract("DocumentRetrieval/CreateLibrary", ex.GetType(), "Connection Error", ex.StackTrace, ExceptionContract.ExceptionCode.error);                             }finally             {                 _service.Close();             }                                      return viewCol;         } } There was a lot more in this class (that I am not including) because i was reusing the grunt work and making other operations with LIst.asmx, For example, updating content types, changing or configuring lists or document libraries. One of the first things I noticed about working with the built in services is that you are really at the mercy of what is available to you. Before creating a document library (Project) I wanted to expose a IsProjectExisting method. This way the integration or data layer could recognize if a library already exists. Well there is no service call or method available to do that check. So this is what I wrote:   public bool DocLibExists(string listName, ref ExceptionContract exContract)         {             try             {                 var allLists = _service.GetListCollection();                                return allLists.ChildNodes.OfType<XmlElement>().ToList().Exists(x => x.Attributes["Title"].Value ==listName);             }             catch (Exception ex)             {                 exContract = new ExceptionContract("DocumentRetrieval/GetList/GetListWSCall", ex.GetType(), "Unable to Retrieve List Collection", ex.StackTrace, ExceptionContract.ExceptionCode.error);             }             return false;         } This really just gets an XMLElement with all the lists. It was then up to me to sift through the clutter and noise and see if Document library already existed. This took a little bit of getting used to. Now instead of working with code, you are working with XMLElement response format from web service. I wrote a LINQ query to go through and find if the attribute "Title" existed and had a value of the listname then it would return True, if not False. I didn't particularly like working this way. Dealing with XMLElement responses and then having to manipulate it to get at the exact data I was looking for. Once the check for the DocLibExists, was done, I would either create the document library or send back an error indicating the document library already existed. Now lets examine the code that actually creates the document library. It does what you are really after, it creates a document library. Notice how the template ID is really an integer. Every document library template in SharePoint has an ID associated with it. Document libraries, Image Library, Custom List, Project Tasks, etc… they all he a unique integer associated with it. Well, that's great but the client came back to me and gave me some specifics that each "project" or document library, should have. They specified they had 3 types of projects. Each project would have unique views, about 10 views for each project. Each Project specified unique configurations (auditing, versioning, content types, etc…) So what turned out to be a simple implementation of creating a document library as a repository for a project, turned out to be quite involved.  The first thing I thought of was to create a template for document library. There are other ways you can do this too. Using the web Service call, you could configure views, versioning, even content types, etc… the only catch is, you have to be working quite extensively with CAML. I am not fond of CAML. I can do it and work with it, I just don't like doing it. It is quite touchy and at times it is quite tough to understand where errors were made with CAML statements. Working with Web Services and CAML proved to be quite annoying. The service call would return a generic error message that did not particularly point me to a CAML statement syntax error, or even a CAML error. I was not sure if it was a security , performance or code based issue. It was quite tough to work with. At times it was difficult to work with because of the way SharePoint handles metadata. There are "Names", "Display Name", and "StaticName" fields. It was quite tough to understand at times, which one to use. So it took a lot of trial and error. There are tools that can help with CAML generation. There is also now intellisense for CAML statements in Visual Studio that might help but ultimately I'm not fond of CAML with Web Services.   So I decided on the template. So my plan was to create create a document library, configure it accordingly and then use The Template Builder that comes with the SharePoint SDK. This tool allows you to create site templates, list template etc… It is quite interesting because it does not generate an STP file, it actually generates an xml definition and a feature you can activate and make that template available on a site or site collection. The first issue I experienced with this is that one of the specifications to this template was that the "All Documents" view was to have 2 web parts on it. Well, it turns out that using the template builder , it did not include the web parts as part of the list template definition it generated. It backed up the settings, the views, the content types but not the custom web parts. I still decided to try this even without the web parts on the page. This new template defined a new Document library definition with a unique ID. The problem was that the service call accepts an int but it only has access to the built in library int definitions. Any new ones added or created will not be available to create. So this made it impossible for me to approach the problem this way.     I should also mention that one of the nice features about SharePoint is the ability to create list templates, back them up and then create lists based on that template. It can all be done by end user administrators. These templates are quite unique because they are saved as an STP file and not an xml definition. I also went this route and tried to see if there was another service call where I could create a document library based no given template name. Nope! none.      After some thinking I decide to implement a WCF service to do this creation for me. I was quite certain that the object model would allow me to create document libraries base on a template in which an ID was required and also templates saved as STP files. Now I don't want to bother with posting the code to contact WCF service because it's self explanatory, but I will post the code that I used to create a list with custom template. public ServiceResult CreateProject(string name, string templateName, string projectId)         {             string siteurl = SPContext.Current.Site.Url;             Guid webguid = SPContext.Current.Web.ID;                        using (SPSite site = new SPSite(siteurl))             {                 using (SPWeb rootweb = site.RootWeb)                 {                     SPListTemplateCollection temps = site.GetCustomListTemplates(rootweb);                     ProcessWeb(siteurl, webguid, web => Act_CreateProject(web, name, templateName, projectId, temps));                 }//SpWeb             }//SPSite              return _globalResult;                   }         private void Act_CreateProject(SPWeb targetsite, string name, string templateName, string projectId, SPListTemplateCollection temps) {                         var temp = temps.Cast<SPListTemplate>().FirstOrDefault(x => x.Name.Equals(templateName));             if (temp != null)             {                             try                 {                                         Guid listGuid = targetsite.Lists.Add(name, "", temp);                     SPList newList = targetsite.Lists[listGuid];                     _globalResult = new ServiceResult(true, "Success", "Success");                 }                 catch (Exception ex)                 {                     _globalResult = new ServiceResult(false, (string.IsNullOrEmpty(ex.Message) ? "None" : ex.Message + " " + templateName), ex.StackTrace.ToString());                 }                                       }        private void ProcessWeb(string siteurl, Guid webguid, Action<SPWeb> action) {                        using (SPSite sitecollection = new SPSite(siteurl)) {                 using (SPWeb web = sitecollection.AllWebs[webguid]) {                     action(web);                 }                     }                  } This code is actually some of the code I implemented for the service. there was a lot more I did on Project Creation which I will cover in my next blog post. I implemented an ACTION method to process the web. This allowed me to properly dispose the SPWEb and SPSite objects and not rewrite this code over and over again. So I implemented a WCF service to create projects for me, this allowed me to do a lot more than just create a document library with a template, it now gave me the flexibility to do just about anything the client wanted at project creation. Once this was implemented , the client came back to me and said, "we reference all our projects with ID's in our application. we want SharePoint to do the same". This has been something I have been doing for a little while now but I do hope that SharePoint 2010 can have more of an answer to this and address it properly. I have been adding metadata to SPWebs through property bag. I believe I have blogged about it before. This time it required metadata added to a document library. No problem!!! I also mentioned these web parts that were to go on the "All Documents" View. I took the opportunity to configure them to the appropriate settings. There were two settings that needed to be set on these web parts. One of them was a Project ID configured in the webpart properties. The following code enhances and replaces the "Act_CreateProject " method above:  private void Act_CreateProject(SPWeb targetsite, string name, string templateName, string projectId, SPListTemplateCollection temps) {                         var temp = temps.Cast<SPListTemplate>().FirstOrDefault(x => x.Name.Equals(templateName));             if (temp != null)             {                 SPLimitedWebPartManager wpmgr = null;                               try                 {                                         Guid listGuid = targetsite.Lists.Add(name, "", temp);                     SPList newList = targetsite.Lists[listGuid];                     SPFolder rootFolder = newList.RootFolder;                     rootFolder.Properties.Add(KEY, projectId);                     rootFolder.Update();                     if (rootFolder.ParentWeb != targetsite)                         rootFolder.ParentWeb.Dispose();                     if (!templateName.Contains("Natural"))                     {                         SPView alldocumentsview = newList.Views.Cast<SPView>().FirstOrDefault(x => x.Title.Equals(ALLDOCUMENTS));                         SPFile alldocfile = targetsite.GetFile(alldocumentsview.ServerRelativeUrl);                         wpmgr = alldocfile.GetLimitedWebPartManager(PersonalizationScope.Shared);                         ConfigureWebPart(wpmgr, projectId, CUSTOMWPNAME);                                              alldocfile.Update();                     }                                        if (newList.ParentWeb != targetsite)                         newList.ParentWeb.Dispose();                     _globalResult = new ServiceResult(true, "Success", "Success");                 }                 catch (Exception ex)                 {                     _globalResult = new ServiceResult(false, (string.IsNullOrEmpty(ex.Message) ? "None" : ex.Message + " " + templateName), ex.StackTrace.ToString());                 }                 finally                 {                     if (wpmgr != null)                     {                         wpmgr.Web.Dispose();                         wpmgr.Dispose();                     }                 }             }                         }       private void ConfigureWebPart(SPLimitedWebPartManager mgr, string prjId, string webpartname)         {             var wp = mgr.WebParts.Cast<System.Web.UI.WebControls.WebParts.WebPart>().FirstOrDefault(x => x.DisplayTitle.Equals(webpartname));             if (wp != null)             {                           (wp as ListRelationshipWebPart.ListRelationshipWebPart).ProjectID = prjId;                 mgr.SaveChanges(wp);             }         }   This Shows you how I was able to set metadata on the document library. It has to be added to the RootFolder of the document library, Unfortunately, the SPList does not have a Property bag that I can add a key\value pair to. It has to be done on the root folder. Now everything in the integration will reference projects by ID's and will not care about names. My, "DocLibExists" will now need to be changed because a web service is not set up to look at property bags.  I had to write another method on the Service to do the equivalent but with ID's instead of names.  The second thing you will notice about the code is the use of the Webpartmanager. I have seen several examples online, and also read a lot about memory leaks, The above code does not produce memory leaks. The web part manager creates an SPWeb, so just dispose it like I did. CONCLUSION This is a long long post so I will stop here for now, I will continue with more comparisons and limitations in my next post. My conclusion for this example is that Web Services will do the trick if you can suffer through CAML and if you are doing some simple operations. For Everything else, there's WCF! **** fireI apologize for the disorganization of this post, I was on a bus on a 12 hour trip to IOWA while I wrote it, I was half asleep and half awake, hopefully it makes enough sense to someone.

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• Using Rich Text Editor (WYSIWYG) in ASP.NET MVC

  - by imran_ku07

     Introduction:          In ASP.NET MVC forum I found some question regarding a sample HTML Rich Text Box Editor(also known as wysiwyg).So i decided to create a sample ASP.NET MVC web application which will use a Rich Text Box Editor. There are are lot of Html Editors are available, but for creating a sample application, i decided to use cross-browser WYSIWYG editor from openwebware. In this article I will discuss what changes needed to work this editor with ASP.NET MVC. Also I had attached the sample application for download at http://www.speedfile.org/155076. Also note that I will only show the important features, not discuss every feature in detail.   Description:          So Let's start create a sample ASP.NET MVC application. You need to add the following script files,         jquery-1.3.2.min.js        jquery_form.js        wysiwyg.js        wysiwyg-settings.js        wysiwyg-popup.js          Just put these files inside Scripts folder. Also put wysiwyg.css in your Content Folder and add the following folders in your project        addons        popups          Also create a empty folder Uploads to store the uploaded images. Next open wysiwyg.js and set your configuration                  // Images Directory        this.ImagesDir = "/addons/imagelibrary/images/";                // Popups Directory        this.PopupsDir = "/popups/";                // CSS Directory File        this.CSSFile = "/Content/wysiwyg.css";              Next create a simple View TextEditor.aspx inside View / Home Folder and add the folllowing HTML.        <%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage" %>            <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">        <html >            <head runat="server">                <title>TextEditor</title>                <script src="../../Scripts/wysiwyg.js" type="text/javascript"></script>                <script src="../../Scripts/wysiwyg-settings.js" type="text/javascript"></script>                <script type="text/javascript">                            WYSIWYG.attach('text', full);                            </script>            </head>            <body>                <% using (Html.BeginForm()){ %>                    <textarea id="text" name="test2" style="width:850px;height:200px;">                    </textarea>                    <input type="submit" value="submit" />                <%} %>            </body>        </html>                  Here i have just added a text area control and a submit button inside a form. Note the id of text area and WYSIWYG.attach function's first parameter is same and next to watch is the HomeController.cs        using System;        using System.Collections.Generic;        using System.Linq;        using System.Web;        using System.Web.Mvc;        using System.IO;        namespace HtmlTextEditor.Controllers        {            [HandleError]            public class HomeController : Controller            {                public ActionResult Index()                {                    ViewData["Message"] = "Welcome to ASP.NET MVC!";                    return View();                }                    public ActionResult About()                {                                return View();                }                        public ActionResult TextEditor()                {                    return View();                }                [AcceptVerbs(HttpVerbs.Post)]                [ValidateInput(false)]                public ActionResult TextEditor(string test2)                {                    Session["html"] = test2;                            return RedirectToAction("Index");                }                        public ActionResult UploadImage()                {                    if (Request.Files[0].FileName != "")                    {                        Request.Files[0].SaveAs(Server.MapPath("~/Uploads/" + Path.GetFileName(Request.Files[0].FileName)));                        return Content(Url.Content("~/Uploads/" + Path.GetFileName(Request.Files[0].FileName)));                    }                    return Content("a");                }            }        }          So simple code, just save the posted Html into Session. Here the parameter of TextArea action is test2 which is same as textarea control name of TextArea.aspx View. Also note ValidateInputAttribute is false, so it's up to you to defends against XSS. Also there is an Action method which simply saves the file inside Upload Folder.          I am uploading the file using Jquery Form Plugin. Here is the code which is found in insert_image.html inside addons folder,        function ChangeImage() {            var myform=document.getElementById("formUpload");                    $(myform).ajaxSubmit({success: function(responseText){                insertImage(responseText);                        window.close();                }            });        }          and here is the Index View which simply renders the html of Editor which was saved in Session        <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %>        <asp:Content ID="indexTitle" ContentPlaceHolderID="TitleContent" runat="server">            Home Page        </asp:Content>        <asp:Content ID="indexContent" ContentPlaceHolderID="MainContent" runat="server">            <h2><%= Html.Encode(ViewData["Message"]) %></h2>            <p>                To learn more about ASP.NET MVC visit <a href="http://asp.net/mvc" title="ASP.NET MVC Website">http://asp.net/mvc</a>.            </p>            <%if (Session["html"] != null){                  Response.Write(Session["html"].ToString());            } %>                    </asp:Content>   Summary:          Hopefully you will enjoy this article. Just download the code and see the effect. From security point, you must handle the XSS attack your self. I had uploaded the sample application in http://www.speedfile.org/155076

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• WLS MBeans

  - by Jani Rautiainen

  WLS provides a set of Managed Beans (MBeans) to configure, monitor and manage WLS resources. We can use the WLS MBeans to automate some of the tasks related to the configuration and maintenance of the WLS instance. The MBeans can be accessed a number of ways; using various UIs and programmatically using Java or WLST Python scripts.For customization development we can use the features to e.g. manage the deployed customization in MDS, control logging levels, automate deployment of dependent libraries etc. This article is an introduction on how to access and use the WLS MBeans. The goal is to illustrate the various access methods in a single article; the details of the features are left to the linked documentation.This article covers Windows based environment, steps for Linux would be similar however there would be some differences e.g. on how the file paths are defined. MBeansThe WLS MBeans can be categorized to runtime and configuration MBeans.The Runtime MBeans can be used to access the runtime information about the server and its resources. The data from runtime beans is only available while the server is running. The runtime beans can be used to e.g. check the state of the server or deployment.The Configuration MBeans contain information about the configuration of servers and resources. The configuration of the domain is stored in the config.xml file and the configuration MBeans can be used to access and modify the configuration data. For more information on the WLS MBeans refer to: Understanding WebLogic Server MBeans WLS MBean reference Java Management Extensions (JMX)We can use JMX APIs to access the WLS MBeans. This allows us to create Java programs to configure, monitor, and manage WLS resources. In order to use the WLS MBeans we need to add the following library into the class-path: WL_HOME\lib\wljmxclient.jar Connecting to a WLS MBean server The WLS MBeans are contained in a Mbean server, depending on the requirement we can connect to (MBean Server / JNDI Name): Domain Runtime MBean Server weblogic.management.mbeanservers.domainruntime Runtime MBean Server weblogic.management.mbeanservers.runtime Edit MBean Server weblogic.management.mbeanservers.edit To connect to the WLS MBean server first we need to create a map containing the credentials; Hashtable<String, String> param = new Hashtable<String, String>(); param.put(Context.SECURITY_PRINCIPAL, "weblogic");        param.put(Context.SECURITY_CREDENTIALS, "weblogic1");        param.put(JMXConnectorFactory.PROTOCOL_PROVIDER_PACKAGES, "weblogic.management.remote"); These define the user, password and package containing the protocol. Next we create the connection: JMXServiceURL serviceURL =     new JMXServiceURL("t3","127.0.0.1",7101,     "/jndi/weblogic.management.mbeanservers.domainruntime"); JMXConnector connector = JMXConnectorFactory.connect(serviceURL, param); MBeanServerConnection connection = connector.getMBeanServerConnection(); With the connection we can now access the MBeans for the WLS instance. For a complete example see Appendix A of this post. For more details refer to Accessing WebLogic Server MBeans with JMX Accessing WLS MBeans The WLS MBeans are structured hierarchically; in order to access content we need to know the path to the MBean we are interested in. The MBean is accessed using “MBeanServerConnection. getAttribute” API.  WLS provides entry points to the hierarchy allowing us to navigate all the WLS MBeans in the hierarchy (MBean Server / JMX object name): Domain Runtime MBean Server com.bea:Name=DomainRuntimeService,Type=weblogic.management.mbeanservers.domainruntime.DomainRuntimeServiceMBean Runtime MBean Servers com.bea:Name=RuntimeService,Type=weblogic.management.mbeanservers.runtime.RuntimeServiceMBean Edit MBean Server com.bea:Name=EditService,Type=weblogic.management.mbeanservers.edit.EditServiceMBean For example we can access the Domain Runtime MBean using: ObjectName service = new ObjectName( "com.bea:Name=DomainRuntimeService," + "Type=weblogic.management.mbeanservers.domainruntime.DomainRuntimeServiceMBean"); Same syntax works for any “child” WLS MBeans e.g. to find out all application deployments we can: ObjectName domainConfig = (ObjectName)connection.getAttribute(service,"DomainConfiguration"); ObjectName[] appDeployments = (ObjectName[])connection.getAttribute(domainConfig,"AppDeployments"); Alternatively we could access the same MBean using the full syntax: ObjectName domainConfig = new ObjectName("com.bea:Location=DefaultDomain,Name=DefaultDomain,Type=Domain"); ObjectName[] appDeployments = (ObjectName[])connection.getAttribute(domainConfig,"AppDeployments"); For more details refer to Accessing WebLogic Server MBeans with JMX Invoking operations on WLS MBeans The WLS MBean operations can be invoked with MBeanServerConnection. invoke API; in the following example we query the state of “AppsLoggerService” application: ObjectName appRuntimeStateRuntime = new ObjectName("com.bea:Name=AppRuntimeStateRuntime,Type=AppRuntimeStateRuntime"); Object[] parameters = { "AppsLoggerService", "DefaultServer" }; String[] signature = { "java.lang.String", "java.lang.String" }; String result = (String)connection.invoke(appRuntimeStateRuntime,"getCurrentState",parameters, signature); The result returned should be "STATE_ACTIVE" assuming the "AppsLoggerService" application is up and running. WebLogic Scripting Tool (WLST) The WebLogic Scripting Tool (WLST) is a command-line scripting environment that we can access the same WLS MBeans. The tool is located under: $MW_HOME\oracle_common\common\bin\wlst.bat Do note that there are several instances of the wlst script under the $MW_HOME, each of them works, however the commands available vary, so we want to use the one under “oracle_common”. The tool is started in offline mode. In offline mode we can access and manipulate the domain configuration. In online mode we can access the runtime information. We connect to the Administration Server : connect("weblogic","weblogic1", "t3://127.0.0.1:7101") In both online and offline modes we can navigate the WLS MBean using commands like "ls" to print content and "cd" to navigate between objects, for example: All the commands available can be obtained with: help('all') For details of the tool refer to WebLogic Scripting Tool and for the commands available WLST Command and Variable Reference. Also do note that the WLST tool can be invoked from Java code in Embedded Mode. Running Scripts The WLST tool allows us to automate tasks using Python scripts in Script Mode. The script can be manually created or recorded by the WLST tool. Example commands of recording a script: startRecording("c:/temp/recording.py") <commands that we want to record> stopRecording() We can run the script from WLST: execfile("c:/temp/recording.py") We can also run the script from the command line: C:\apps\Oracle\Middleware\oracle_common\common\bin\wlst.cmd c:/temp/recording.py There are various sample scripts are provided with the WLS instance. UI to Access the WLS MBeans There are various UIs through which we can access the WLS MBeans. Oracle Enterprise Manager Fusion Middleware Control Oracle WebLogic Server Administration Console Fusion Middleware Control MBean Browser In the integrated JDeveloper environment only the Oracle WebLogic Server Administration Console is available to us. For more information refer to the documentation, one noteworthy feature in the console is the ability to record WLST scripts based on the navigation. In addition to the UIs above the JConsole included in the JDK can be used to access the WLS MBeans. The JConsole needs to be started with specific parameter to force WLS objects to be used and jar files in the classpath: "C:\apps\Oracle\Middleware\jdk160_24\bin\jconsole" -J-Djava.class.path=C:\apps\Oracle\Middleware\jdk160_24\lib\jconsole.jar;C:\apps\Oracle\Middleware\jdk160_24\lib\tools.jar;C:\apps\Oracle\Middleware\wlserver_10.3\server\lib\wljmxclient.jar -J-Djmx.remote.protocol.provider.pkgs=weblogic.management.remote For more details refer to the Accessing Custom MBeans from JConsole. Summary In this article we have covered various ways we can access and use the WLS MBeans in context of integrated WLS in JDeveloper to be used for Fusion Application customization development. References Developing Custom Management Utilities With JMX for Oracle WebLogic Server Accessing WebLogic Server MBeans with JMX WebLogic Server MBean Reference WebLogic Scripting Tool WLST Command and Variable Reference Appendix A package oracle.apps.test; import java.io.IOException;import java.net.MalformedURLException;import java.util.Hashtable;import javax.management.MBeanServerConnection;import javax.management.MalformedObjectNameException;import javax.management.ObjectName;import javax.management.remote.JMXConnector;import javax.management.remote.JMXConnectorFactory;import javax.management.remote.JMXServiceURL;import javax.naming.Context;/** * This class contains simple examples on how to access WLS MBeans using JMX. */public class BlogExample {    /**     * Connection to the WLS MBeans     */    private MBeanServerConnection connection;    /**     * Constructor that takes in the connection information for the      * domain and obtains the resources from WLS MBeans using JMX.     * @param hostName host name to connect to for the WLS server     * @param port port to connect to for the WLS server     * @param userName user name to connect to for the WLS server     * @param password password to connect to for the WLS server     */    public BlogExample(String hostName, String port, String userName,                       String password) {        super();        try {            initConnection(hostName, port, userName, password);        } catch (Exception e) {            throw new RuntimeException("Unable to connect to the domain " +                                       hostName + ":" + port);        }    }    /**     * Default constructor.     * Tries to create connection with default values. Runtime exception will be     * thrown if the default values are not used in the local instance.     */    public BlogExample() {        this("127.0.0.1", "7101", "weblogic", "weblogic1");    }    /**     * Initializes the JMX connection to the WLS Beans     * @param hostName host name to connect to for the WLS server     * @param port port to connect to for the WLS server     * @param userName user name to connect to for the WLS server     * @param password password to connect to for the WLS server     * @throws IOException error connecting to the WLS MBeans     * @throws MalformedURLException error connecting to the WLS MBeans     * @throws MalformedObjectNameException error connecting to the WLS MBeans     */    private void initConnection(String hostName, String port, String userName,                                String password)                                 throws IOException, MalformedURLException,                                        MalformedObjectNameException {        String protocol = "t3";        String jndiroot = "/jndi/";        String mserver = "weblogic.management.mbeanservers.domainruntime";        JMXServiceURL serviceURL =            new JMXServiceURL(protocol, hostName, Integer.valueOf(port),                              jndiroot + mserver);        Hashtable<String, String> h = new Hashtable<String, String>();        h.put(Context.SECURITY_PRINCIPAL, userName);        h.put(Context.SECURITY_CREDENTIALS, password);        h.put(JMXConnectorFactory.PROTOCOL_PROVIDER_PACKAGES,              "weblogic.management.remote");        JMXConnector connector = JMXConnectorFactory.connect(serviceURL, h);        connection = connector.getMBeanServerConnection();    }    /**     * Main method used to invoke the logic for testing     * @param args arguments passed to the program     */    public static void main(String[] args) {        BlogExample blogExample = new BlogExample();        blogExample.testEntryPoint();        blogExample.testDirectAccess();        blogExample.testInvokeOperation();    }    /**     * Example of using an entry point to navigate the WLS MBean hierarchy.     */    public void testEntryPoint() {        try {            System.out.println("testEntryPoint");            ObjectName service =             new ObjectName("com.bea:Name=DomainRuntimeService,Type=" +"weblogic.management.mbeanservers.domainruntime.DomainRuntimeServiceMBean");            ObjectName domainConfig =                (ObjectName)connection.getAttribute(service,                                                    "DomainConfiguration");            ObjectName[] appDeployments =                (ObjectName[])connection.getAttribute(domainConfig,                                                      "AppDeployments");            for (ObjectName appDeployment : appDeployments) {                String resourceIdentifier =                    (String)connection.getAttribute(appDeployment,                                                    "SourcePath");                System.out.println(resourceIdentifier);            }        } catch (Exception e) {            throw new RuntimeException(e);        }    }    /**     * Example of accessing WLS MBean directly with a full reference.     * This does the same thing as testEntryPoint in slightly difference way.     */    public void testDirectAccess() {        try {            System.out.println("testDirectAccess");            ObjectName appDeployment =                new ObjectName("com.bea:Location=DefaultDomain,"+                               "Name=AppsLoggerService,Type=AppDeployment");            String resourceIdentifier =                (String)connection.getAttribute(appDeployment, "SourcePath");            System.out.println(resourceIdentifier);        } catch (Exception e) {            throw new RuntimeException(e);        }    }    /**     * Example of invoking operation on a WLS MBean.     */    public void testInvokeOperation() {        try {            System.out.println("testInvokeOperation");            ObjectName appRuntimeStateRuntime =                new ObjectName("com.bea:Name=AppRuntimeStateRuntime,"+                               "Type=AppRuntimeStateRuntime");            String identifier = "AppsLoggerService";            String serverName = "DefaultServer";            Object[] parameters = { identifier, serverName };            String[] signature = { "java.lang.String", "java.lang.String" };            String result =                (String)connection.invoke(appRuntimeStateRuntime, "getCurrentState",                                          parameters, signature);            System.out.println("State of " + identifier + " = " + result);        } catch (Exception e) {            throw new RuntimeException(e);        }    }}

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• ANTS CLR and Memory Profiler In Depth Review (Part 1 of 2 &ndash; CLR Profiler)

  - by ToStringTheory

  One of the things that people might not know about me, is my obsession to make my code as efficient as possible.  Many people might not realize how much of a task or undertaking that this might be, but it is surely a task as monumental as climbing Mount Everest, except this time it is a challenge for the mind…  In trying to make code efficient, there are many different factors that play a part – size of project or solution, tiers, language used, experience and training of the programmer, technologies used, maintainability of the code – the list can go on for quite some time. I spend quite a bit of time when developing trying to determine what is the best way to implement a feature to accomplish the efficiency that I look to achieve.  One program that I have recently come to learn about – Red Gate ANTS Performance (CLR) and Memory profiler gives me tools to accomplish that job more efficiently as well.  In this review, I am going to cover some of the features of the ANTS profiler set by compiling some hideous example code to test against. Notice As a member of the Geeks With Blogs Influencers program, one of the perks is the ability to review products, in exchange for a free license to the program.  I have not let this affect my opinions of the product in any way, and Red Gate nor Geeks With Blogs has tried to influence my opinion regarding this product in any way. Introduction The ANTS Profiler pack provided by Red Gate was something that I had not heard of before receiving an email regarding an offer to review it for a license.  Since I look to make my code efficient, it was a no brainer for me to try it out!  One thing that I have to say took me by surprise is that upon downloading the program and installing it you fill out a form for your usual contact information.  Sure enough within 2 hours, I received an email from a sales representative at Red Gate asking if she could help me to achieve the most out of my trial time so it wouldn’t go to waste.  After replying to her and explaining that I was looking to review its feature set, she put me in contact with someone that setup a demo session to give me a quick rundown of its features via an online meeting.  After having dealt with a massive ordeal with one of my utility companies and their complete lack of customer service, Red Gates friendly and helpful representatives were a breath of fresh air, and something I was thankful for. ANTS CLR Profiler The ANTS CLR profiler is the thing I want to focus on the most in this post, so I am going to dive right in now. Install was simple and took no time at all.  It installed both the profiler for the CLR and Memory, but also visual studio extensions to facilitate the usage of the profilers (click any images for full size images): The Visual Studio menu options (under ANTS menu) Starting the CLR Performance Profiler from the start menu yields this window If you follow the instructions after launching the program from the start menu (Click File > New Profiling Session to start a new project), you are given a dialog with plenty of options for profiling: The New Session dialog.  Lots of options.  One thing I noticed is that the buttons in the lower right were half-covered by the panel of the application.  If I had to guess, I would imagine that this is caused by my DPI settings being set to 125%.  This is a problem I have seen in other applications as well that don’t scale well to different dpi scales. The profiler options give you the ability to profile: .NET Executable ASP.NET web application (hosted in IIS) ASP.NET web application (hosted in IIS express) ASP.NET web application (hosted in Cassini Web Development Server) SharePoint web application (hosted in IIS) Silverlight 4+ application Windows Service COM+ server XBAP (local XAML browser application) Attach to an already running .NET 4 process Choosing each option provides a varying set of other variables/options that one can set including options such as application arguments, operating path, record I/O performance performance counters to record (43 counters in all!), etc…  All in all, they give you the ability to profile many different .Net project types, and make it simple to do so.  In most cases of my using this application, I would be using the built in Visual Studio extensions, as they automatically start a new profiling project in ANTS with the options setup, and start your program, however RedGate has made it easy enough to profile outside of Visual Studio as well. On the flip side of this, as someone who lives most of their work life in Visual Studio, one thing I do wish is that instead of opening an entirely separate application/gui to perform profiling after launching, that instead they would provide a Visual Studio panel with the information, and integrate more of the profiling project information into Visual Studio.  So, now that we have an idea of what options that the profiler gives us, its time to test its abilities and features. Horrendous Example Code – Prime Number Generator One of my interests besides development, is Physics and Math – what I went to college for.  I have especially always been interested in prime numbers, as they are something of a mystery…  So, I decided that I would go ahead and to test the abilities of the profiler, I would write a small program, website, and library to generate prime numbers in the quantity that you ask for.  I am going to start off with some terrible code, and show how I would see the profiler being used as a development tool. First off, the IPrimes interface (all code is downloadable at the end of the post): interface IPrimes { IEnumerable<int> GetPrimes(int retrieve); } Simple enough, right?  Anything that implements the interface will (hopefully) provide an IEnumerable of int, with the quantity specified in the parameter argument.  Next, I am going to implement this interface in the most basic way: public class DumbPrimes : IPrimes { public IEnumerable<int> GetPrimes(int retrieve) { //store a list of primes already found var _foundPrimes = new List<int>() { 2, 3 }; //if i ask for 1 or two primes, return what asked for if (retrieve <= _foundPrimes.Count()) return _foundPrimes.Take(retrieve); //the next number to look at int _analyzing = 4; //since I already determined I don't have enough //execute at least once, and until quantity is sufficed do { //assume prime until otherwise determined bool isPrime = true; //start dividing at 2 //divide until number is reached, or determined not prime for (int i = 2; i < _analyzing && isPrime; i++) { //if (i) goes into _analyzing without a remainder, //_analyzing is NOT prime if (_analyzing % i == 0) isPrime = false; } //if it is prime, add to found list if (isPrime) _foundPrimes.Add(_analyzing); //increment number to analyze next _analyzing++; } while (_foundPrimes.Count() < retrieve); return _foundPrimes; } } This is the simplest way to get primes in my opinion.  Checking each number by the straight definition of a prime – is it divisible by anything besides 1 and itself. I have included this code in a base class library for my solution, as I am going to use it to demonstrate a couple of features of ANTS.  This class library is consumed by a simple non-MVVM WPF application, and a simple MVC4 website.  I will not post the WPF code here inline, as it is simply an ObservableCollection<int>, a label, two textbox’s, and a button. Starting a new Profiling Session So, in Visual Studio, I have just completed my first stint developing the GUI and DumbPrimes IPrimes class, so now I want to check my codes efficiency by profiling it.  All I have to do is build the solution (surprised initiating a profiling session doesn’t do this, but I suppose I can understand it), and then click the ANTS menu, followed by Profile Performance.  I am then greeted by the profiler starting up and already monitoring my program live: You are provided with a realtime graph at the top, and a pane at the bottom giving you information on how to proceed.  I am going to start by asking my program to show me the first 15000 primes: After the program finally began responding again (I did all the work on the main UI thread – how bad!), I stopped the profiler, which did kill the process of my program too.  One important thing to note, is that the profiler by default wants to give you a lot of detail about the operation – line hit counts, time per line, percent time per line, etc…  The important thing to remember is that this itself takes a lot of time.  When running my program without the profiler attached, it can generate the 15000 primes in 5.18 seconds, compared to 74.5 seconds – almost a 1500 percent increase.  While this may seem like a lot, remember that there is a trade off.  It may be WAY more inefficient, however, I am able to drill down and make improvements to specific problem areas, and then decrease execution time all around. Analyzing the Profiling Session After clicking ‘Stop Profiling’, the process running my application stopped, and the entire execution time was automatically selected by ANTS, and the results shown below: Now there are a number of interesting things going on here, I am going to cover each in a section of its own: Real Time Performance Counter Bar (top of screen) At the top of the screen, is the real time performance bar.  As your application is running, this will constantly update with the currently selected performance counters status.  A couple of cool things to note are the fact that you can drag a selection around specific time periods to drill down the detail views in the lower 2 panels to information pertaining to only that period. After selecting a time period, you can bookmark a section and name it, so that it is easy to find later, or after reloaded at a later time.  You can also zoom in, out, or fit the graph to the space provided – useful for drilling down. It may be hard to see, but at the top of the processor time graph below the time ticks, but above the red usage graph, there is a green bar. This bar shows at what times a method that is selected in the ‘Call tree’ panel is called. Very cool to be able to click on a method and see at what times it made an impact. As I said before, ANTS provides 43 different performance counters you can hook into.  Click the arrow next to the Performance tab at the top will allow you to change between different counters if you have them selected: Method Call Tree, ADO.Net Database Calls, File IO – Detail Panel Red Gate really hit the mark here I think. When you select a section of the run with the graph, the call tree populates to fill a hierarchical tree of method calls, with information regarding each of the methods.   By default, methods are hidden where the source is not provided (framework type code), however, Red Gate has integrated Reflector into ANTS, so even if you don’t have source for something, you can select a method and get the source if you want.  Methods are also hidden where the impact is seen as insignificant – methods that are only executed for 1% of the time of the overall calling methods time; in other words, working on making them better is not where your efforts should be focused. – Smart! Source Panel – Detail Panel The source panel is where you can see line level information on your code, showing the code for the currently selected method from the Method Call Tree.  If the code is not available, Reflector takes care of it and shows the code anyways! As you can notice, there does seem to be a problem with how ANTS determines what line is the actual line that a call is completed on.  I have suspicions that this may be due to some of the inline code optimizations that the CLR applies upon compilation of the assembly.  In a method with comments, the problem is much more severe: As you can see here, apparently the most offending code in my base library was a comment – *gasp*!  Removing the comments does help quite a bit, however I hope that Red Gate works on their counter algorithm soon to improve the logic on positioning for statistics: I did a small test just to demonstrate the lines are correct without comments. For me, it isn’t a deal breaker, as I can usually determine the correct placements by looking at the application code in the region and determining what makes sense, but it is something that would probably build up some irritation with time. Feature – Suggest Method for Optimization A neat feature to really help those in need of a pointer, is the menu option under tools to automatically suggest methods to optimize/improve: Nice feature – clicking it filters the call tree and stars methods that it thinks are good candidates for optimization.  I do wish that they would have made it more visible for those of use who aren’t great on sight: Process Integration I do think that this could have a place in my process.  After experimenting with the profiler, I do think it would be a great benefit to do some development, testing, and then after all the bugs are worked out, use the profiler to check on things to make sure nothing seems like it is hogging more than its fair share.  For example, with this program, I would have developed it, ran it, tested it – it works, but slowly. After looking at the profiler, and seeing the massive amount of time spent in 1 method, I might go ahead and try to re-implement IPrimes (I actually would probably rewrite the offending code, but so that I can distribute both sets of code easily, I’m just going to make another implementation of IPrimes).  Using two pieces of knowledge about prime numbers can make this method MUCH more efficient – prime numbers fall into two buckets 6k+/-1 , and a number is prime if it is not divisible by any other primes before it: public class SmartPrimes : IPrimes { public IEnumerable<int> GetPrimes(int retrieve) { //store a list of primes already found var _foundPrimes = new List<int>() { 2, 3 }; //if i ask for 1 or two primes, return what asked for if (retrieve <= _foundPrimes.Count()) return _foundPrimes.Take(retrieve); //the next number to look at int _k = 1; //since I already determined I don't have enough //execute at least once, and until quantity is sufficed do { //assume prime until otherwise determined bool isPrime = true; int potentialPrime; //analyze 6k-1 //assign the value to potential potentialPrime = 6 * _k - 1; //if there are any primes that divise this, it is NOT a prime number //using PLINQ for quick boost isPrime = !_foundPrimes.AsParallel() .Any(prime => potentialPrime % prime == 0); //if it is prime, add to found list if (isPrime) _foundPrimes.Add(potentialPrime); if (_foundPrimes.Count() == retrieve) break; //analyze 6k+1 //assign the value to potential potentialPrime = 6 * _k + 1; //if there are any primes that divise this, it is NOT a prime number //using PLINQ for quick boost isPrime = !_foundPrimes.AsParallel() .Any(prime => potentialPrime % prime == 0); //if it is prime, add to found list if (isPrime) _foundPrimes.Add(potentialPrime); //increment k to analyze next _k++; } while (_foundPrimes.Count() < retrieve); return _foundPrimes; } } Now there are definitely more things I can do to help make this more efficient, but for the scope of this example, I think this is fine (but still hideous)! Profiling this now yields a happy surprise 27 seconds to generate the 15000 primes with the profiler attached, and only 1.43 seconds without.  One important thing I wanted to call out though was the performance graph now: Notice anything odd?  The %Processor time is above 100%.  This is because there is now more than 1 core in the operation.  A better label for the chart in my mind would have been %Core time, but to each their own. Another odd thing I noticed was that the profiler seemed to be spot on this time in my DumbPrimes class with line details in source, even with comments..  Odd. Profiling Web Applications The last thing that I wanted to cover, that means a lot to me as a web developer, is the great amount of work that Red Gate put into the profiler when profiling web applications.  In my solution, I have a simple MVC4 application setup with 1 page, a single input form, that will output prime values as my WPF app did.  Launching the profiler from Visual Studio as before, nothing is really different in the profiler window, however I did receive a UAC prompt for a Red Gate helper app to integrate with the web server without notification. After requesting 500, 1000, 2000, and 5000 primes, and looking at the profiler session, things are slightly different from before: As you can see, there are 4 spikes of activity in the processor time graph, but there is also something new in the call tree: That’s right – ANTS will actually group method calls by get/post operations, so it is easier to find out what action/page is giving the largest problems…  Pretty cool in my mind! Overview Overall, I think that Red Gate ANTS CLR Profiler has a lot to offer, however I think it also has a long ways to go.  3 Biggest Pros: Ability to easily drill down from time graph, to method calls, to source code Wide variety of counters to choose from when profiling your application Excellent integration/grouping of methods being called from web applications by request – BRILLIANT! 3 Biggest Cons: Issue regarding line details in source view Nit pick – Processor time vs. Core time Nit pick – Lack of full integration with Visual Studio Ratings Ease of Use (7/10) – I marked down here because of the problems with the line level details and the extra work that that entails, and the lack of better integration with Visual Studio. Effectiveness (10/10) – I believe that the profiler does EXACTLY what it purports to do.  Especially with its large variety of performance counters, a definite plus! Features (9/10) – Besides the real time performance monitoring, and the drill downs that I’ve shown here, ANTS also has great integration with ADO.Net, with the ability to show database queries run by your application in the profiler.  This, with the line level details, the web request grouping, reflector integration, and various options to customize your profiling session I think create a great set of features! Customer Service (10/10) – My entire experience with Red Gate personnel has been nothing but good.  their people are friendly, helpful, and happy! UI / UX (8/10) – The interface is very easy to get around, and all of the options are easy to find.  With a little bit of poking around, you’ll be optimizing Hello World in no time flat! Overall (8/10) – Overall, I am happy with the Performance Profiler and its features, as well as with the service I received when working with the Red Gate personnel.  I WOULD recommend you trying the application and seeing if it would fit into your process, BUT, remember there are still some kinks in it to hopefully be worked out. My next post will definitely be shorter (hopefully), but thank you for reading up to here, or skipping ahead!  Please, if you do try the product, drop me a message and let me know what you think!  I would love to hear any opinions you may have on the product. Code Feel free to download the code I used above – download via DropBox

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• ANTS Memory Profiler 7.0 Review

  - by Michael B. McLaughlin

  (This is my first review as a part of the GeeksWithBlogs.net Influencers program. It’s a program in which I (and the others who have been selected for it) get the opportunity to check out new products and services and write reviews about them. We don’t get paid for this, but we do generally get to keep a copy of the software or retain an account for some period of time on the service that we review. In this case I received a copy of Red Gate Software’s ANTS Memory Profiler 7.0, which was released in January. I don’t have any upgrade rights nor is my review guided, restrained, influenced, or otherwise controlled by Red Gate or anyone else. But I do get to keep the software license. I will always be clear about what I received whenever I do a review – I leave it up to you to decide whether you believe I can be objective. I believe I can be. If I used something and really didn’t like it, keeping a copy of it wouldn’t be worth anything to me. In that case though, I would simply uninstall/deactivate/whatever the software or service and tell the company what I didn’t like about it so they could (hopefully) make it better in the future. I don’t think it’d be polite to write up a terrible review, nor do I think it would be a particularly good use of my time. There are people who get paid for a living to review things, so I leave it to them to tell you what they think is bad and why. I’ll only spend my time telling you about things I think are good.) Overview of Common .NET Memory Problems When coming to land of managed memory from the wilds of unmanaged code, it’s easy to say to one’s self, “Wow! Now I never have to worry about memory problems again!” But this simply isn’t true. Managed code environments, such as .NET, make many, many things easier. You will never have to worry about memory corruption due to a bad pointer, for example (unless you’re working with unsafe code, of course). But managed code has its own set of memory concerns. For example, failing to unsubscribe from events when you are done with them leaves the publisher of an event with a reference to the subscriber. If you eliminate all your own references to the subscriber, then that memory is effectively lost since the GC won’t delete it because of the publishing object’s reference. When the publishing object itself becomes subject to garbage collection then you’ll get that memory back finally, but that could take a very long time depending of the life of the publisher. Another common source of resource leaks is failing to properly release unmanaged resources. When writing a class that contains members that hold unmanaged resources (e.g. any of the Stream-derived classes, IsolatedStorageFile, most classes ending in “Reader” or “Writer”), you should always implement IDisposable, making sure to use a properly written Dispose method. And when you are using an instance of a class that implements IDisposable, you should always make sure to use a 'using' statement in order to ensure that the object’s unmanaged resources are disposed of properly. (A ‘using’ statement is a nicer, cleaner looking, and easier to use version of a try-finally block. The compiler actually translates it as though it were a try-finally block. Note that Code Analysis warning 2202 (CA2202) will often be triggered by nested using blocks. A properly written dispose method ensures that it only runs once such that calling dispose multiple times should not be a problem. Nonetheless, CA2202 exists and if you want to avoid triggering it then you should write your code such that only the innermost IDisposable object uses a ‘using’ statement, with any outer code making use of appropriate try-finally blocks instead). Then, of course, there are situations where you are operating in a memory-constrained environment or else you want to limit or even eliminate allocations within a certain part of your program (e.g. within the main game loop of an XNA game) in order to avoid having the GC run. On the Xbox 360 and Windows Phone 7, for example, for every 1 MB of heap allocations you make, the GC runs; the added time of a GC collection can cause a game to drop frames or run slowly thereby making it look bad. Eliminating allocations (or else minimizing them and calling an explicit Collect at an appropriate time) is a common way of avoiding this (the other way is to simplify your heap so that the GC’s latency is low enough not to cause performance issues). ANTS Memory Profiler 7.0 When the opportunity to review Red Gate’s recently released ANTS Memory Profiler 7.0 arose, I jumped at it. In order to review it, I was given a free copy (which does not include upgrade rights for future versions) which I am allowed to keep. For those of you who are familiar with ANTS Memory Profiler, you can find a list of new features and enhancements here. If you are an experienced .NET developer who is familiar with .NET memory management issues, ANTS Memory Profiler is great. More importantly still, if you are new to .NET development or you have no experience or limited experience with memory profiling, ANTS Memory Profiler is awesome. From the very beginning, it guides you through the process of memory profiling. If you’re experienced and just want dive in however, it doesn’t get in your way. The help items GAHSFLASHDAJLDJA are well designed and located right next to the UI controls so that they are easy to find without being intrusive. When you first launch it, it presents you with a “Getting Started” screen that contains links to “Memory profiling video tutorials”, “Strategies for memory profiling”, and the “ANTS Memory Profiler forum”. I’m normally the kind of person who looks at a screen like that only to find the “Don’t show this again” checkbox. Since I was doing a review, though, I decided I should examine them. I was pleasantly surprised. The overview video clocks in at three minutes and fifty seconds. It begins by showing you how to get started profiling an application. It explains that profiling is done by taking memory snapshots periodically while your program is running and then comparing them. ANTS Memory Profiler (I’m just going to call it “ANTS MP” from here) analyzes these snapshots in the background while your application is running. It briefly mentions a new feature in Version 7, a new API that give you the ability to trigger snapshots from within your application’s source code (more about this below). You can also, and this is the more common way you would do it, take a memory snapshot at any time from within the ANTS MP window by clicking the “Take Memory Snapshot” button in the upper right corner. The overview video goes on to demonstrate a basic profiling session on an application that pulls information from a database and displays it. It shows how to switch which snapshots you are comparing, explains the different sections of the Summary view and what they are showing, and proceeds to show you how to investigate memory problems using the “Instance Categorizer” to track the path from an object (or set of objects) to the GC’s root in order to find what things along the path are holding a reference to it/them. For a set of objects, you can then click on it and get the “Instance List” view. This displays all of the individual objects (including their individual sizes, values, etc.) of that type which share the same path to the GC root. You can then click on one of the objects to generate an “Instance Retention Graph” view. This lets you track directly up to see the reference chain for that individual object. In the overview video, it turned out that there was an event handler which was holding on to a reference, thereby keeping a large number of strings that should have been freed in memory. Lastly the video shows the “Class List” view, which lets you dig in deeply to find problems that might not have been clear when following the previous workflow. Once you have at least one memory snapshot you can begin analyzing. The main interface is in the “Analysis” tab. You can also switch to the “Session Overview” tab, which gives you several bar charts highlighting basic memory data about the snapshots you’ve taken. If you hover over the individual bars (and the individual colors in bars that have more than one), you will see a detailed text description of what the bar is representing visually. The Session Overview is good for a quick summary of memory usage and information about the different heaps. You are going to spend most of your time in the Analysis tab, but it’s good to remember that the Session Overview is there to give you some quick feedback on basic memory usage stats. As described above in the summary of the overview video, there is a certain natural workflow to the Analysis tab. You’ll spin up your application and take some snapshots at various times such as before and after clicking a button to open a window or before and after closing a window. Taking these snapshots lets you examine what is happening with memory. You would normally expect that a lot of memory would be freed up when closing a window or exiting a document. By taking snapshots before and after performing an action like that you can see whether or not the memory is really being freed. If you already know an area that’s giving you trouble, you can run your application just like normal until just before getting to that part and then you can take a few strategic snapshots that should help you pin down the problem. Something the overview didn’t go into is how to use the “Filters” section at the bottom of ANTS MP together with the Class List view in order to narrow things down. The video tutorials page has a nice 3 minute intro video called “How to use the filters”. It’s a nice introduction and covers some of the basics. I’m going to cover a bit more because I think they’re a really neat, really helpful feature. Large programs can bring up thousands of classes. Even simple programs can instantiate far more classes than you might realize. In a basic .NET 4 WPF application for example (and when I say basic, I mean just MainWindow.xaml with a button added to it), the unfiltered Class List view will have in excess of 1000 classes (my simple test app had anywhere from 1066 to 1148 classes depending on which snapshot I was using as the “Current” snapshot). This is amazing in some ways as it shows you how in stark detail just how immensely powerful the WPF framework is. But hunting through 1100 classes isn’t productive, no matter how cool it is that there are that many classes instantiated and doing all sorts of awesome things. Let’s say you wanted to examine just the classes your application contains source code for (in my simple example, that would be the MainWindow and App). Under “Basic Filters”, click on “Classes with source” under “Show only…”. Voilà. Down from 1070 classes in the snapshot I was using as “Current” to 2 classes. If you then click on a class’s name, it will show you (to the right of the class name) two little icon buttons. Hover over them and you will see that you can click one to view the Instance Categorizer for the class and another to view the Instance List for the class. You can also show classes based on which heap they live on. If you chose both a Baseline snapshot and a Current snapshot then you can use the “Comparing snapshots” filters to show only: “New objects”; “Surviving objects”; “Survivors in growing classes”; or “Zombie objects” (if you aren’t sure what one of these means, you can click the helpful “?” in a green circle icon to bring up a popup that explains them and provides context). Remember that your selection(s) under the “Show only…” heading will still apply, so you should update those selections to make sure you are seeing the view you want. There are also links under the “What is my memory problem?” heading that can help you diagnose the problems you are seeing including one for “I don’t know which kind I have” for situations where you know generally that your application has some problems but aren’t sure what the behavior you have been seeing (OutOfMemoryExceptions, continually growing memory usage, larger memory use than expected at certain points in the program). The Basic Filters are not the only filters there are. “Filter by Object Type” gives you the ability to filter by: “Objects that are disposable”; “Objects that are/are not disposed”; “Objects that are/are not GC roots” (GC roots are things like static variables); and “Objects that implement _______”. “Objects that implement” is particularly neat. Once you check the box, you can then add one or more classes and interfaces that an object must implement in order to survive the filtering. Lastly there is “Filter by Reference”, which gives you the option to pare down the list based on whether an object is “Kept in memory exclusively by” a particular item, a class/interface, or a namespace; whether an object is “Referenced by” one or more of those choices; and whether an object is “Never referenced by” one or more of those choices. Remember that filtering is cumulative, so anything you had set in one of the filter sections still remains in effect unless and until you go back and change it. There’s quite a bit more to ANTS MP – it’s a very full featured product – but I think I touched on all of the most significant pieces. You can use it to debug: a .NET executable; an ASP.NET web application (running on IIS); an ASP.NET web application (running on Visual Studio’s built-in web development server); a Silverlight 4 browser application; a Windows service; a COM+ server; and even something called an XBAP (local XAML browser application). You can also attach to a .NET 4 process to profile an application that’s already running. The startup screen also has a large number of “Charting Options” that let you adjust which statistics ANTS MP should collect. The default selection is a good, minimal set. It’s worth your time to browse through the charting options to examine other statistics that may also help you diagnose a particular problem. The more statistics ANTS MP collects, the longer it will take to collect statistics. So just turning everything on is probably a bad idea. But the option to selectively add in additional performance counters from the extensive list could be a very helpful thing for your memory profiling as it lets you see additional data that might provide clues about a particular problem that has been bothering you. ANTS MP integrates very nicely with all versions of Visual Studio that support plugins (i.e. all of the non-Express versions). Just note that if you choose “Profile Memory” from the “ANTS” menu that it will launch profiling for whichever project you have set as the Startup project. One quick tip from my experience so far using ANTS MP: if you want to properly understand your memory usage in an application you’ve written, first create an “empty” version of the type of project you are going to profile (a WPF application, an XNA game, etc.) and do a quick profiling session on that so that you know the baseline memory usage of the framework itself. By “empty” I mean just create a new project of that type in Visual Studio then compile it and run it with profiling – don’t do anything special or add in anything (except perhaps for any external libraries you’re planning to use). The first thing I tried ANTS MP out on was a demo XNA project of an editor that I’ve been working on for quite some time that involves a custom extension to XNA’s content pipeline. The first time I ran it and saw the unmanaged memory usage I was convinced I had some horrible bug that was creating extra copies of texture data (the demo project didn’t have a lot of texture data so when I saw a lot of unmanaged memory I instantly figured I was doing something wrong). Then I thought to run an empty project through and when I saw that the amount of unmanaged memory was virtually identical, it dawned on me that the CLR itself sits in unmanaged memory and that (thankfully) there was nothing wrong with my code! Quite a relief. Earlier, when discussing the overview video, I mentioned the API that lets you take snapshots from within your application. I gave it a quick trial and it’s very easy to integrate and make use of and is a really nice addition (especially for projects where you want to know what, if any, allocations there are in a specific, complicated section of code). The only concern I had was that if I hadn’t watched the overview video I might never have known it existed. Even then it took me five minutes of hunting around Red Gate’s website before I found the “Taking snapshots from your code" article that explains what DLL you need to add as a reference and what method of what class you should call in order to take an automatic snapshot (including the helpful warning to wrap it in a try-catch block since, under certain circumstances, it can raise an exception, such as trying to call it more than 5 times in 30 seconds. The difficulty in discovering and then finding information about the automatic snapshots API was one thing I thought could use improvement. Another thing I think would make it even better would be local copies of the webpages it links to. Although I’m generally always connected to the internet, I imagine there are more than a few developers who aren’t or who are behind very restrictive firewalls. For them (and for me, too, if my internet connection happens to be down), it would be nice to have those documents installed locally or to have the option to download an additional “documentation” package that would add local copies. Another thing that I wish could be easier to manage is the Filters area. Finding and setting individual filters is very easy as is understanding what those filter do. And breaking it up into three sections (basic, by object, and by reference) makes sense. But I could easily see myself running a long profiling session and forgetting that I had set some filter a long while earlier in a different filter section and then spending quite a bit of time trying to figure out why some problem that was clearly visible in the data wasn’t showing up in, e.g. the instance list before remembering to check all the filters for that one setting that was only culling a few things from view. Some sort of indicator icon next to the filter section names that appears you have at least one filter set in that area would be a nice visual clue to remind me that “oh yeah, I told it to only show objects on the Gen 2 heap! That’s why I’m not seeing those instances of the SuperMagic class!” Something that would be nice (but that Red Gate cannot really do anything about) would be if this could be used in Windows Phone 7 development. If Microsoft and Red Gate could work together to make this happen (even if just on the WP7 emulator), that would be amazing. Especially given the memory constraints that apps and games running on mobile devices need to work within, a good memory profiler would be a phenomenally helpful tool. If anyone at Microsoft reads this, it’d be really great if you could make something like that happen. Perhaps even a (subsidized) custom version just for WP7 development. (For XNA games, of course, you can create a Windows version of the game and use ANTS MP on the Windows version in order to get a better picture of your memory situation. For Silverlight on WP7, though, there’s quite a bit of educated guess work and WeakReference creation followed by forced collections in order to find the source of a memory problem.) The only other thing I found myself wanting was a “Back” button. Between my Windows Phone 7, Zune, and other things, I’ve grown very used to having a “back stack” that lets me just navigate back to where I came from. The ANTS MP interface is surprisingly easy to use given how much it lets you do, and once you start using it for any amount of time, you learn all of the different areas such that you know where to go. And it does remember the state of the areas you were previously in, of course. So if you go to, e.g., the Instance Retention Graph from the Class List and then return back to the Class List, it will remember which class you had selected and all that other state information. Still, a “Back” button would be a welcome addition to a future release. Bottom Line ANTS Memory Profiler is not an inexpensive tool. But my time is valuable. I can easily see ANTS MP saving me enough time tracking down memory problems to justify it on a cost basis. More importantly to me, knowing what is happening memory-wise in my programs and having the confidence that my code doesn’t have any hidden time bombs in it that will cause it to OOM if I leave it running for longer than I do when I spin it up real quickly for debugging or just to see how a new feature looks and feels is a good feeling. It’s a feeling that I like having and want to continue to have. I got the current version for free in order to review it. Having done so, I’ve now added it to my must-have tools and will gladly lay out the money for the next version when it comes out. It has a 14 day free trial, so if you aren’t sure if it’s right for you or if you think it seems interesting but aren’t really sure if it’s worth shelling out the money for it, give it a try.

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• C#/.NET Little Wonders: The ConcurrentDictionary

  - by James Michael Hare

  Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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• Much Ado About Nothing: Stub Objects

  - by user9154181

  The Solaris 11 link-editor (ld) contains support for a new type of object that we call a stub object. A stub object is a shared object, built entirely from mapfiles, that supplies the same linking interface as the real object, while containing no code or data. Stub objects cannot be executed — the runtime linker will kill any process that attempts to load one. However, you can link to a stub object as a dependency, allowing the stub to act as a proxy for the real version of the object. You may well wonder if there is a point to producing an object that contains nothing but linking interface. As it turns out, stub objects are very useful for building large bodies of code such as Solaris. In the last year, we've had considerable success in applying them to one of our oldest and thorniest build problems. In this discussion, I will describe how we came to invent these objects, and how we apply them to building Solaris. This posting explains where the idea for stub objects came from, and details our long and twisty journey from hallway idea to standard link-editor feature. I expect that these details are mainly of interest to those who work on Solaris and its makefiles, those who have done so in the past, and those who work with other similar bodies of code. A subsequent posting will omit the history and background details, and instead discuss how to build and use stub objects. If you are mainly interested in what stub objects are, and don't care about the underlying software war stories, I encourage you to skip ahead. The Long Road To Stubs This all started for me with an email discussion in May of 2008, regarding a change request that was filed in 2002, entitled: 4631488 lib/Makefile is too patient: .WAITs should be reduced This CR encapsulates a number of cronic issues with Solaris builds: We build Solaris with a parallel make (dmake) that tries to build as much of the code base in parallel as possible. There is a lot of code to build, and we've long made use of parallelized builds to get the job done quicker. This is even more important in today's world of massively multicore hardware. Solaris contains a large number of executables and shared objects. Executables depend on shared objects, and shared objects can depend on each other. Before you can build an object, you need to ensure that the objects it needs have been built. This implies a need for serialization, which is in direct opposition to the desire to build everying in parallel. To accurately build objects in the right order requires an accurate set of make rules defining the things that depend on each other. This sounds simple, but the reality is quite complex. In practice, having programmers explicitly specify these dependencies is a losing strategy: It's really hard to get right. It's really easy to get it wrong and never know it because things build anyway. Even if you get it right, it won't stay that way, because dependencies between objects can change over time, and make cannot help you detect such drifing. You won't know that you got it wrong until the builds break. That can be a long time after the change that triggered the breakage happened, making it hard to connect the cause and the effect. Usually this happens just before a release, when the pressure is on, its hard to think calmly, and there is no time for deep fixes. As a poor compromise, the libraries in core Solaris were built using a set of grossly incomplete hand written rules, supplemented with a number of dmake .WAIT directives used to group the libraries into sets of non-interacting groups that can be built in parallel because we think they don't depend on each other. From time to time, someone will suggest that we could analyze the built objects themselves to determine their dependencies and then generate make rules based on those relationships. This is possible, but but there are complications that limit the usefulness of that approach: To analyze an object, you have to build it first. This is a classic chicken and egg scenario. You could analyze the results of a previous build, but then you're not necessarily going to get accurate rules for the current code. It should be possible to build the code without having a built workspace available. The analysis will take time, and remember that we're constantly trying to make builds faster, not slower. By definition, such an approach will always be approximate, and therefore only incremantally more accurate than the hand written rules described above. The hand written rules are fast and cheap, while this idea is slow and complex, so we stayed with the hand written approach. Solaris was built that way, essentially forever, because these are genuinely difficult problems that had no easy answer. The makefiles were full of build races in which the right outcomes happened reliably for years until a new machine or a change in build server workload upset the accidental balance of things. After figuring out what had happened, you'd mutter "How did that ever work?", add another incomplete and soon to be inaccurate make dependency rule to the system, and move on. This was not a satisfying solution, as we tend to be perfectionists in the Solaris group, but we didn't have a better answer. It worked well enough, approximately. And so it went for years. We needed a different approach — a new idea to cut the Gordian Knot. In that discussion from May 2008, my fellow linker-alien Rod Evans had the initial spark that lead us to a game changing series of realizations: The link-editor is used to link objects together, but it only uses the ELF metadata in the object, consisting of symbol tables, ELF versioning sections, and similar data. Notably, it does not look at, or understand, the machine code that makes an object useful at runtime. If you had an object that only contained the ELF metadata for a dependency, but not the code or data, the link-editor would find it equally useful for linking, and would never know the difference. Call it a stub object. In the core Solaris OS, we require all objects to be built with a link-editor mapfile that describes all of its publically available functions and data. Could we build a stub object using the mapfile for the real object? It ought to be very fast to build stub objects, as there are no input objects to process. Unlike the real object, stub objects would not actually require any dependencies, and so, all of the stubs for the entire system could be built in parallel. When building the real objects, one could link against the stub objects instead of the real dependencies. This means that all the real objects can be built built in parallel too, without any serialization. We could replace a system that requires perfect makefile rules with a system that requires no ordering rules whatsoever. The results would be considerably more robust. We immediately realized that this idea had potential, but also that there were many details to sort out, lots of work to do, and that perhaps it wouldn't really pan out. As is often the case, it would be necessary to do the work and see how it turned out. Following that conversation, I set about trying to build a stub object. We determined that a faithful stub has to do the following: Present the same set of global symbols, with the same ELF versioning, as the real object. Functions are simple — it suffices to have a symbol of the right type, possibly, but not necessarily, referencing a null function in its text segment. Copy relocations make data more complicated to stub. The possibility of a copy relocation means that when you create a stub, the data symbols must have the actual size of the real data. Any error in this will go uncaught at link time, and will cause tragic failures at runtime that are very hard to diagnose. For reasons too obscure to go into here, involving tentative symbols, it is also important that the data reside in bss, or not, matching its placement in the real object. If the real object has more than one symbol pointing at the same data item, we call these aliased symbols. All data symbols in the stub object must exhibit the same aliasing as the real object. We imagined the stub library feature working as follows: A command line option to ld tells it to produce a stub rather than a real object. In this mode, only mapfiles are examined, and any object or shared libraries on the command line are are ignored. The extra information needed (function or data, size, and bss details) would be added to the mapfile. When building the real object instead of the stub, the extra information for building stubs would be validated against the resulting object to ensure that they match. In exploring these ideas, I immediately run headfirst into the reality of the original mapfile syntax, a subject that I would later write about as The Problem(s) With Solaris SVR4 Link-Editor Mapfiles. The idea of extending that poor language was a non-starter. Until a better mapfile syntax became available, which seemed unlikely in 2008, the solution could not involve extentions to the mapfile syntax. Instead, we cooked up the idea (hack) of augmenting mapfiles with stylized comments that would carry the necessary information. A typical definition might look like: # DATA(i386) __iob 0x3c0 # DATA(amd64,sparcv9) __iob 0xa00 # DATA(sparc) __iob 0x140 iob; A further problem then became clear: If we can't extend the mapfile syntax, then there's no good way to extend ld with an option to produce stub objects, and to validate them against the real objects. The idea of having ld read comments in a mapfile and parse them for content is an unacceptable hack. The entire point of comments is that they are strictly for the human reader, and explicitly ignored by the tool. Taking all of these speed bumps into account, I made a new plan: A perl script reads the mapfiles, generates some small C glue code to produce empty functions and data definitions, compiles and links the stub object from the generated glue code, and then deletes the generated glue code. Another perl script used after both objects have been built, to compare the real and stub objects, using data from elfdump, and validate that they present the same linking interface. By June 2008, I had written the above, and generated a stub object for libc. It was a useful prototype process to go through, and it allowed me to explore the ideas at a deep level. Ultimately though, the result was unsatisfactory as a basis for real product. There were so many issues: The use of stylized comments were fine for a prototype, but not close to professional enough for shipping product. The idea of having to document and support it was a large concern. The ideal solution for stub objects really does involve having the link-editor accept the same arguments used to build the real object, augmented with a single extra command line option. Any other solution, such as our prototype script, will require makefiles to be modified in deeper ways to support building stubs, and so, will raise barriers to converting existing code. A validation script that rederives what the linker knew when it built an object will always be at a disadvantage relative to the actual linker that did the work. A stub object should be identifyable as such. In the prototype, there was no tag or other metadata that would let you know that they weren't real objects. Being able to identify a stub object in this way means that the file command can tell you what it is, and that the runtime linker can refuse to try and run a program that loads one. At that point, we needed to apply this prototype to building Solaris. As you might imagine, the task of modifying all the makefiles in the core Solaris code base in order to do this is a massive task, and not something you'd enter into lightly. The quality of the prototype just wasn't good enough to justify that sort of time commitment, so I tabled the project, putting it on my list of long term things to think about, and moved on to other work. It would sit there for a couple of years. Semi-coincidentally, one of the projects I tacked after that was to create a new mapfile syntax for the Solaris link-editor. We had wanted to do something about the old mapfile syntax for many years. Others before me had done some paper designs, and a great deal of thought had already gone into the features it should, and should not have, but for various reasons things had never moved beyond the idea stage. When I joined Sun in late 2005, I got involved in reviewing those things and thinking about the problem. Now in 2008, fresh from relearning for the Nth time why the old mapfile syntax was a huge impediment to linker progress, it seemed like the right time to tackle the mapfile issue. Paving the way for proper stub object support was not the driving force behind that effort, but I certainly had them in mind as I moved forward. The new mapfile syntax, which we call version 2, integrated into Nevada build snv_135 in in February 2010: 6916788 ld version 2 mapfile syntax PSARC/2009/688 Human readable and extensible ld mapfile syntax In order to prove that the new mapfile syntax was adequate for general purpose use, I had also done an overhaul of the ON consolidation to convert all mapfiles to use the new syntax, and put checks in place that would ensure that no use of the old syntax would creep back in. That work went back into snv_144 in June 2010: 6916796 OSnet mapfiles should use version 2 link-editor syntax That was a big putback, modifying 517 files, adding 18 new files, and removing 110 old ones. I would have done this putback anyway, as the work was already done, and the benefits of human readable syntax are obvious. However, among the justifications listed in CR 6916796 was this We anticipate adding additional features to the new mapfile language that will be applicable to ON, and which will require all sharable object mapfiles to use the new syntax. I never explained what those additional features were, and no one asked. It was premature to say so, but this was a reference to stub objects. By that point, I had already put together a working prototype link-editor with the necessary support for stub objects. I was pleased to find that building stubs was indeed very fast. On my desktop system (Ultra 24), an amd64 stub for libc can can be built in a fraction of a second: % ptime ld -64 -z stub -o stubs/libc.so.1 -G -hlibc.so.1 \ -ztext -zdefs -Bdirect ... real 0.019708910 user 0.010101680 sys 0.008528431 In order to go from prototype to integrated link-editor feature, I knew that I would need to prove that stub objects were valuable. And to do that, I knew that I'd have to switch the Solaris ON consolidation to use stub objects and evaluate the outcome. And in order to do that experiment, ON would first need to be converted to version 2 mapfiles. Sub-mission accomplished. Normally when you design a new feature, you can devise reasonably small tests to show it works, and then deploy it incrementally, letting it prove its value as it goes. The entire point of stub objects however was to demonstrate that they could be successfully applied to an extremely large and complex code base, and specifically to solve the Solaris build issues detailed above. There was no way to finesse the matter — in order to move ahead, I would have to successfully use stub objects to build the entire ON consolidation and demonstrate their value. In software, the need to boil the ocean can often be a warning sign that things are trending in the wrong direction. Conversely, sometimes progress demands that you build something large and new all at once. A big win, or a big loss — sometimes all you can do is try it and see what happens. And so, I spent some time staring at ON makefiles trying to get a handle on how things work, and how they'd have to change. It's a big and messy world, full of complex interactions, unspecified dependencies, special cases, and knowledge of arcane makefile features... ...and so, I backed away, put it down for a few months and did other work... ...until the fall, when I felt like it was time to stop thinking and pondering (some would say stalling) and get on with it. Without stubs, the following gives a simplified high level view of how Solaris is built: An initially empty directory known as the proto, and referenced via the ROOT makefile macro is established to receive the files that make up the Solaris distribution. A top level setup rule creates the proto area, and performs operations needed to initialize the workspace so that the main build operations can be launched, such as copying needed header files into the proto area. Parallel builds are launched to build the kernel (usr/src/uts), libraries (usr/src/lib), and commands. The install makefile target builds each item and delivers a copy to the proto area. All libraries and executables link against the objects previously installed in the proto, implying the need to synchronize the order in which things are built. Subsequent passes run lint, and do packaging. Given this structure, the additions to use stub objects are: A new second proto area is established, known as the stub proto and referenced via the STUBROOT makefile macro. The stub proto has the same structure as the real proto, but is used to hold stub objects. All files in the real proto are delivered as part of the Solaris product. In contrast, the stub proto is used to build the product, and then thrown away. A new target is added to library Makefiles called stub. This rule builds the stub objects. The ld command is designed so that you can build a stub object using the same ld command line you'd use to build the real object, with the addition of a single -z stub option. This means that the makefile rules for building the stub objects are very similar to those used to build the real objects, and many existing makefile definitions can be shared between them. A new target is added to the Makefiles called stubinstall which delivers the stub objects built by the stub rule into the stub proto. These rules reuse much of existing plumbing used by the existing install rule. The setup rule runs stubinstall over the entire lib subtree as part of its initialization. All libraries and executables link against the objects in the stub proto rather than the main proto, and can therefore be built in parallel without any synchronization. There was no small way to try this that would yield meaningful results. I would have to take a leap of faith and edit approximately 1850 makefiles and 300 mapfiles first, trusting that it would all work out. Once the editing was done, I'd type make and see what happened. This took about 6 weeks to do, and there were many dark days when I'd question the entire project, or struggle to understand some of the many twisted and complex situations I'd uncover in the makefiles. I even found a couple of new issues that required changes to the new stub object related code I'd added to ld. With a substantial amount of encouragement and help from some key people in the Solaris group, I eventually got the editing done and stub objects for the entire workspace built. I found that my desktop system could build all the stub objects in the workspace in roughly a minute. This was great news, as it meant that use of the feature is effectively free — no one was likely to notice or care about the cost of building them. After another week of typing make, fixing whatever failed, and doing it again, I succeeded in getting a complete build! The next step was to remove all of the make rules and .WAIT statements dedicated to controlling the order in which libraries under usr/src/lib are built. This came together pretty quickly, and after a few more speed bumps, I had a workspace that built cleanly and looked like something you might actually be able to integrate someday. This was a significant milestone, but there was still much left to do. I turned to doing full nightly builds. Every type of build (open, closed, OpenSolaris, export, domestic) had to be tried. Each type failed in a new and unique way, requiring some thinking and rework. As things came together, I became aware of things that could have been done better, simpler, or cleaner, and those things also required some rethinking, the seeking of wisdom from others, and some rework. After another couple of weeks, it was in close to final form. My focus turned towards the end game and integration. This was a huge workspace, and needed to go back soon, before changes in the gate would made merging increasingly difficult. At this point, I knew that the stub objects had greatly simplified the makefile logic and uncovered a number of race conditions, some of which had been there for years. I assumed that the builds were faster too, so I did some builds intended to quantify the speedup in build time that resulted from this approach. It had never occurred to me that there might not be one. And so, I was very surprised to find that the wall clock build times for a stock ON workspace were essentially identical to the times for my stub library enabled version! This is why it is important to always measure, and not just to assume. One can tell from first principles, based on all those removed dependency rules in the library makefile, that the stub object version of ON gives dmake considerably more opportunities to overlap library construction. Some hypothesis were proposed, and shot down: Could we have disabled dmakes parallel feature? No, a quick check showed things being build in parallel. It was suggested that we might be I/O bound, and so, the threads would be mostly idle. That's a plausible explanation, but system stats didn't really support it. Plus, the timing between the stub and non-stub cases were just too suspiciously identical. Are our machines already handling as much parallelism as they are capable of, and unable to exploit these additional opportunities? Once again, we didn't see the evidence to back this up. Eventually, a more plausible and obvious reason emerged: We build the libraries and commands (usr/src/lib, usr/src/cmd) in parallel with the kernel (usr/src/uts). The kernel is the long leg in that race, and so, wall clock measurements of build time are essentially showing how long it takes to build uts. Although it would have been nice to post a huge speedup immediately, we can take solace in knowing that stub objects simplify the makefiles and reduce the possibility of race conditions. The next step in reducing build time should be to find ways to reduce or overlap the uts part of the builds. When that leg of the build becomes shorter, then the increased parallelism in the libs and commands will pay additional dividends. Until then, we'll just have to settle for simpler and more robust. And so, I integrated the link-editor support for creating stub objects into snv_153 (November 2010) with 6993877 ld should produce stub objects PSARC/2010/397 ELF Stub Objects followed by the work to convert the ON consolidation in snv_161 (February 2011) with 7009826 OSnet should use stub objects 4631488 lib/Makefile is too patient: .WAITs should be reduced This was a huge putback, with 2108 modified files, 8 new files, and 2 removed files. Due to the size, I was allowed a window after snv_160 closed in which to do the putback. It went pretty smoothly for something this big, a few more preexisting race conditions would be discovered and addressed over the next few weeks, and things have been quiet since then. Conclusions and Looking Forward Solaris has been built with stub objects since February. The fact that developers no longer specify the order in which libraries are built has been a big success, and we've eliminated an entire class of build error. That's not to say that there are no build races left in the ON makefiles, but we've taken a substantial bite out of the problem while generally simplifying and improving things. The introduction of a stub proto area has also opened some interesting new possibilities for other build improvements. As this article has become quite long, and as those uses do not involve stub objects, I will defer that discussion to a future article.

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• Using Stub Objects

  - by user9154181

  Having told the long and winding tale of where stub objects came from and how we use them to build Solaris, I'd like to focus now on the the nuts and bolts of building and using them. The following new features were added to the Solaris link-editor (ld) to support the production and use of stub objects: -z stub This new command line option informs ld that it is to build a stub object rather than a normal object. In this mode, it accepts the same command line arguments as usual, but will quietly ignore any objects and sharable object dependencies. STUB_OBJECT Mapfile Directive In order to build a stub version of an object, its mapfile must specify the STUB_OBJECT directive. When producing a non-stub object, the presence of STUB_OBJECT causes the link-editor to perform extra validation to ensure that the stub and non-stub objects will be compatible. ASSERT Mapfile Directive All data symbols exported from the object must have an ASSERT symbol directive in the mapfile that declares them as data and supplies the size, binding, bss attributes, and symbol aliasing details. When building the stub objects, the information in these ASSERT directives is used to create the data symbols. When building the real object, these ASSERT directives will ensure that the real object matches the linking interface presented by the stub. Although ASSERT was added to the link-editor in order to support stub objects, they are a general purpose feature that can be used independently of stub objects. For instance you might choose to use an ASSERT directive if you have a symbol that must have a specific address in order for the object to operate properly and you want to automatically ensure that this will always be the case. The material presented here is derived from a document I originally wrote during the development effort, which had the dual goals of providing supplemental materials for the stub object PSARC case, and as a set of edits that were eventually applied to the Oracle Solaris Linker and Libraries Manual (LLM). The Solaris 11 LLM contains this information in a more polished form. Stub Objects A stub object is a shared object, built entirely from mapfiles, that supplies the same linking interface as the real object, while containing no code or data. Stub objects cannot be used at runtime. However, an application can be built against a stub object, where the stub object provides the real object name to be used at runtime, and then use the real object at runtime. When building a stub object, the link-editor ignores any object or library files specified on the command line, and these files need not exist in order to build a stub. Since the compilation step can be omitted, and because the link-editor has relatively little work to do, stub objects can be built very quickly. Stub objects can be used to solve a variety of build problems: Speed Modern machines, using a version of make with the ability to parallelize operations, are capable of compiling and linking many objects simultaneously, and doing so offers significant speedups. However, it is typical that a given object will depend on other objects, and that there will be a core set of objects that nearly everything else depends on. It is necessary to impose an ordering that builds each object before any other object that requires it. This ordering creates bottlenecks that reduce the amount of parallelization that is possible and limits the overall speed at which the code can be built. Complexity/Correctness In a large body of code, there can be a large number of dependencies between the various objects. The makefiles or other build descriptions for these objects can become very complex and difficult to understand or maintain. The dependencies can change as the system evolves. This can cause a given set of makefiles to become slightly incorrect over time, leading to race conditions and mysterious rare build failures. Dependency Cycles It might be desirable to organize code as cooperating shared objects, each of which draw on the resources provided by the other. Such cycles cannot be supported in an environment where objects must be built before the objects that use them, even though the runtime linker is fully capable of loading and using such objects if they could be built. Stub shared objects offer an alternative method for building code that sidesteps the above issues. Stub objects can be quickly built for all the shared objects produced by the build. Then, all the real shared objects and executables can be built in parallel, in any order, using the stub objects to stand in for the real objects at link-time. Afterwards, the executables and real shared objects are kept, and the stub shared objects are discarded. Stub objects are built from a mapfile, which must satisfy the following requirements. The mapfile must specify the STUB_OBJECT directive. This directive informs the link-editor that the object can be built as a stub object, and as such causes the link-editor to perform validation and sanity checking intended to guarantee that an object and its stub will always provide identical linking interfaces. All function and data symbols that make up the external interface to the object must be explicitly listed in the mapfile. The mapfile must use symbol scope reduction ('*'), to remove any symbols not explicitly listed from the external interface. All global data exported from the object must have an ASSERT symbol attribute in the mapfile to specify the symbol type, size, and bss attributes. In the case where there are multiple symbols that reference the same data, the ASSERT for one of these symbols must specify the TYPE and SIZE attributes, while the others must use the ALIAS attribute to reference this primary symbol. Given such a mapfile, the stub and real versions of the shared object can be built using the same command line for each, adding the '-z stub' option to the link for the stub object, and omiting the option from the link for the real object. To demonstrate these ideas, the following code implements a shared object named idx5, which exports data from a 5 element array of integers, with each element initialized to contain its zero-based array index. This data is available as a global array, via an alternative alias data symbol with weak binding, and via a functional interface. % cat idx5.c int _idx5[5] = { 0, 1, 2, 3, 4 }; #pragma weak idx5 = _idx5 int idx5_func(int index) { if ((index 4)) return (-1); return (_idx5[index]); } A mapfile is required to describe the interface provided by this shared object. % cat mapfile $mapfile_version 2 STUB_OBJECT; SYMBOL_SCOPE { _idx5 { ASSERT { TYPE=data; SIZE=4[5] }; }; idx5 { ASSERT { BINDING=weak; ALIAS=_idx5 }; }; idx5_func; local: *; }; The following main program is used to print all the index values available from the idx5 shared object. % cat main.c #include <stdio.h> extern int _idx5[5], idx5[5], idx5_func(int); int main(int argc, char **argv) { int i; for (i = 0; i The following commands create a stub version of this shared object in a subdirectory named stublib. elfdump is used to verify that the resulting object is a stub. The command used to build the stub differs from that of the real object only in the addition of the -z stub option, and the use of a different output file name. This demonstrates the ease with which stub generation can be added to an existing makefile. % cc -Kpic -G -M mapfile -h libidx5.so.1 idx5.c -o stublib/libidx5.so.1 -zstub % ln -s libidx5.so.1 stublib/libidx5.so % elfdump -d stublib/libidx5.so | grep STUB [11] FLAGS_1 0x4000000 [ STUB ] The main program can now be built, using the stub object to stand in for the real shared object, and setting a runpath that will find the real object at runtime. However, as we have not yet built the real object, this program cannot yet be run. Attempts to cause the system to load the stub object are rejected, as the runtime linker knows that stub objects lack the actual code and data found in the real object, and cannot execute. % cc main.c -L stublib -R '$ORIGIN/lib' -lidx5 -lc % ./a.out ld.so.1: a.out: fatal: libidx5.so.1: open failed: No such file or directory Killed % LD_PRELOAD=stublib/libidx5.so.1 ./a.out ld.so.1: a.out: fatal: stublib/libidx5.so.1: stub shared object cannot be used at runtime Killed We build the real object using the same command as we used to build the stub, omitting the -z stub option, and writing the results to a different file. % cc -Kpic -G -M mapfile -h libidx5.so.1 idx5.c -o lib/libidx5.so.1 Once the real object has been built in the lib subdirectory, the program can be run. % ./a.out [0] 0 0 0 [1] 1 1 1 [2] 2 2 2 [3] 3 3 3 [4] 4 4 4 Mapfile Changes The version 2 mapfile syntax was extended in a number of places to accommodate stub objects. Conditional Input The version 2 mapfile syntax has the ability conditionalize mapfile input using the $if control directive. As you might imagine, these directives are used frequently with ASSERT directives for data, because a given data symbol will frequently have a different size in 32 or 64-bit code, or on differing hardware such as x86 versus sparc. The link-editor maintains an internal table of names that can be used in the logical expressions evaluated by $if and $elif. At startup, this table is initialized with items that describe the class of object (_ELF32 or _ELF64) and the type of the target machine (_sparc or _x86). We found that there were a small number of cases in the Solaris code base in which we needed to know what kind of object we were producing, so we added the following new predefined items in order to address that need: NameMeaning ...... _ET_DYNshared object _ET_EXECexecutable object _ET_RELrelocatable object ...... STUB_OBJECT Directive The new STUB_OBJECT directive informs the link-editor that the object described by the mapfile can be built as a stub object. STUB_OBJECT; A stub shared object is built entirely from the information in the mapfiles supplied on the command line. When the -z stub option is specified to build a stub object, the presence of the STUB_OBJECT directive in a mapfile is required, and the link-editor uses the information in symbol ASSERT attributes to create global symbols that match those of the real object. When the real object is built, the presence of STUB_OBJECT causes the link-editor to verify that the mapfiles accurately describe the real object interface, and that a stub object built from them will provide the same linking interface as the real object it represents. All function and data symbols that make up the external interface to the object must be explicitly listed in the mapfile. The mapfile must use symbol scope reduction ('*'), to remove any symbols not explicitly listed from the external interface. All global data in the object is required to have an ASSERT attribute that specifies the symbol type and size. If the ASSERT BIND attribute is not present, the link-editor provides a default assertion that the symbol must be GLOBAL. If the ASSERT SH_ATTR attribute is not present, or does not specify that the section is one of BITS or NOBITS, the link-editor provides a default assertion that the associated section is BITS. All data symbols that describe the same address and size are required to have ASSERT ALIAS attributes specified in the mapfile. If aliased symbols are discovered that do not have an ASSERT ALIAS specified, the link fails and no object is produced. These rules ensure that the mapfiles contain a description of the real shared object's linking interface that is sufficient to produce a stub object with a completely compatible linking interface. SYMBOL_SCOPE/SYMBOL_VERSION ASSERT Attribute The SYMBOL_SCOPE and SYMBOL_VERSION mapfile directives were extended with a symbol attribute named ASSERT. The syntax for the ASSERT attribute is as follows: ASSERT { ALIAS = symbol_name; BINDING = symbol_binding; TYPE = symbol_type; SH_ATTR = section_attributes; SIZE = size_value; SIZE = size_value[count]; }; The ASSERT attribute is used to specify the expected characteristics of the symbol. The link-editor compares the symbol characteristics that result from the link to those given by ASSERT attributes. If the real and asserted attributes do not agree, a fatal error is issued and the output object is not created. In normal use, the link editor evaluates the ASSERT attribute when present, but does not require them, or provide default values for them. The presence of the STUB_OBJECT directive in a mapfile alters the interpretation of ASSERT to require them under some circumstances, and to supply default assertions if explicit ones are not present. See the definition of the STUB_OBJECT Directive for the details. When the -z stub command line option is specified to build a stub object, the information provided by ASSERT attributes is used to define the attributes of the global symbols provided by the object. ASSERT accepts the following: ALIAS Name of a previously defined symbol that this symbol is an alias for. An alias symbol has the same type, value, and size as the main symbol. The ALIAS attribute is mutually exclusive to the TYPE, SIZE, and SH_ATTR attributes, and cannot be used with them. When ALIAS is specified, the type, size, and section attributes are obtained from the alias symbol. BIND Specifies an ELF symbol binding, which can be any of the STB_ constants defined in <sys/elf.h>, with the STB_ prefix removed (e.g. GLOBAL, WEAK). TYPE Specifies an ELF symbol type, which can be any of the STT_ constants defined in <sys/elf.h>, with the STT_ prefix removed (e.g. OBJECT, COMMON, FUNC). In addition, for compatibility with other mapfile usage, FUNCTION and DATA can be specified, for STT_FUNC and STT_OBJECT, respectively. TYPE is mutually exclusive to ALIAS, and cannot be used in conjunction with it. SH_ATTR Specifies attributes of the section associated with the symbol. The section_attributes that can be specified are given in the following table: Section AttributeMeaning BITSSection is not of type SHT_NOBITS NOBITSSection is of type SHT_NOBITS SH_ATTR is mutually exclusive to ALIAS, and cannot be used in conjunction with it. SIZE Specifies the expected symbol size. SIZE is mutually exclusive to ALIAS, and cannot be used in conjunction with it. The syntax for the size_value argument is as described in the discussion of the SIZE attribute below. SIZE The SIZE symbol attribute existed before support for stub objects was introduced. It is used to set the size attribute of a given symbol. This attribute results in the creation of a symbol definition. Prior to the introduction of the ASSERT SIZE attribute, the value of a SIZE attribute was always numeric. While attempting to apply ASSERT SIZE to the objects in the Solaris ON consolidation, I found that many data symbols have a size based on the natural machine wordsize for the class of object being produced. Variables declared as long, or as a pointer, will be 4 bytes in size in a 32-bit object, and 8 bytes in a 64-bit object. Initially, I employed the conditional $if directive to handle these cases as follows: $if _ELF32 foo { ASSERT { TYPE=data; SIZE=4 } }; bar { ASSERT { TYPE=data; SIZE=20 } }; $elif _ELF64 foo { ASSERT { TYPE=data; SIZE=8 } }; bar { ASSERT { TYPE=data; SIZE=40 } }; $else $error UNKNOWN ELFCLASS $endif I found that the situation occurs frequently enough that this is cumbersome. To simplify this case, I introduced the idea of the addrsize symbolic name, and of a repeat count, which together make it simple to specify machine word scalar or array symbols. Both the SIZE, and ASSERT SIZE attributes support this syntax: The size_value argument can be a numeric value, or it can be the symbolic name addrsize. addrsize represents the size of a machine word capable of holding a memory address. The link-editor substitutes the value 4 for addrsize when building 32-bit objects, and the value 8 when building 64-bit objects. addrsize is useful for representing the size of pointer variables and C variables of type long, as it automatically adjusts for 32 and 64-bit objects without requiring the use of conditional input. The size_value argument can be optionally suffixed with a count value, enclosed in square brackets. If count is present, size_value and count are multiplied together to obtain the final size value. Using this feature, the example above can be written more naturally as: foo { ASSERT { TYPE=data; SIZE=addrsize } }; bar { ASSERT { TYPE=data; SIZE=addrsize[5] } }; Exported Global Data Is Still A Bad Idea As you can see, the additional plumbing added to the Solaris link-editor to support stub objects is minimal. Furthermore, about 90% of that plumbing is dedicated to handling global data. We have long advised against global data exported from shared objects. There are many ways in which global data does not fit well with dynamic linking. Stub objects simply provide one more reason to avoid this practice. It is always better to export all data via a functional interface. You should always hide your data, and make it available to your users via a function that they can call to acquire the address of the data item. However, If you do have to support global data for a stub, perhaps because you are working with an already existing object, it is still easilily done, as shown above. Oracle does not like us to discuss hypothetical new features that don't exist in shipping product, so I'll end this section with a speculation. It might be possible to do more in this area to ease the difficulty of dealing with objects that have global data that the users of the library don't need. Perhaps someday... Conclusions It is easy to create stub objects for most objects. If your library only exports function symbols, all you have to do to build a faithful stub object is to add STUB_OBJECT; and then to use the same link command you're currently using, with the addition of the -z stub option. Happy Stubbing!

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• Error when Eclipse started and now my package explorer is empty!

  - by carpenteri

  Friends, Just a quick introduction, I'm currently learning Java, using a combination of the Head First Java book and Eclipse. Everything was going well until tonight! When I started up Eclipse tonight, I saw an error message which I didn't pay attention to (I know! I know!) and acknowledged after which the project explorer was empty where it used to contain my Head First project! After a quick "google" I found the workspace.metadata.log and the errors are shown below. The version of Eclipse I am using is: 20100218-1602 and the only plugin that I use is egit. Any help would be much appreciated. Thanks !SESSION 2010-06-08 19:24:33.841 ----------------------------------------------- eclipse.buildId=unknown java.version=1.5.0_22 java.vendor=Sun Microsystems Inc. BootLoader constants: OS=win32, ARCH=x86, WS=win32, NL=en_GB Framework arguments: -product org.eclipse.epp.package.java.product Command-line arguments: -os win32 -ws win32 -arch x86 -product org.eclipse.epp.package.java.product !ENTRY org.eclipse.ui.workbench 4 2 2010-06-08 19:24:36.475 !MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.ui.workbench". !STACK 1 org.eclipse.ui.WorkbenchException: Content is not allowed in prolog. at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:121) at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:64) at org.eclipse.ui.internal.Workbench$49.run(Workbench.java:1895) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42) at org.eclipse.ui.internal.Workbench.restoreState(Workbench.java:1890) at org.eclipse.ui.internal.WorkbenchConfigurer.restoreState(WorkbenchConfigurer.java:183) at org.eclipse.ui.application.WorkbenchAdvisor$1.run(WorkbenchAdvisor.java:781) Caused by: org.xml.sax.SAXParseException: Content is not allowed in prolog. at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292) at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:94) ... 6 more !SUBENTRY 1 org.eclipse.ui 4 0 2010-06-08 19:24:36.475 !MESSAGE Content is not allowed in prolog. !STACK 0 org.xml.sax.SAXParseException: Content is not allowed in prolog. at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292) at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:94) at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:64) at org.eclipse.ui.internal.Workbench$49.run(Workbench.java:1895) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42) at org.eclipse.ui.internal.Workbench.restoreState(Workbench.java:1890) at org.eclipse.ui.internal.WorkbenchConfigurer.restoreState(WorkbenchConfigurer.java:183) at org.eclipse.ui.application.WorkbenchAdvisor$1.run(WorkbenchAdvisor.java:781) !SUBENTRY 1 org.eclipse.ui 4 0 2010-06-08 19:24:36.475 !MESSAGE Content is not allowed in prolog. !STACK 0 org.xml.sax.SAXParseException: Content is not allowed in prolog. at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292) at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:94) at org.eclipse.ui.XMLMemento.createReadRoot(XMLMemento.java:64) at org.eclipse.ui.internal.Workbench$49.run(Workbench.java:1895) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42) at org.eclipse.ui.internal.Workbench.restoreState(Workbench.java:1890) at org.eclipse.ui.internal.WorkbenchConfigurer.restoreState(WorkbenchConfigurer.java:183) at org.eclipse.ui.application.WorkbenchAdvisor$1.run(WorkbenchAdvisor.java:781) !ENTRY org.eclipse.jdt.ui 4 10001 2010-06-08 19:24:41.442 !MESSAGE Internal Error !STACK 1 org.eclipse.jdt.internal.ui.JavaUIException: Problems reading information from XML 'OpenTypeHistory.xml' at org.eclipse.jdt.internal.corext.util.History.createException(History.java:70) at org.eclipse.jdt.internal.corext.util.History.load(History.java:257) at org.eclipse.jdt.internal.corext.util.History.load(History.java:166) at org.eclipse.jdt.internal.corext.util.OpenTypeHistory.<init>(OpenTypeHistory.java:199) at org.eclipse.jdt.internal.corext.util.OpenTypeHistory.getInstance(OpenTypeHistory.java:185) at org.eclipse.jdt.internal.ui.JavaPlugin.initializeAfterLoad(JavaPlugin.java:381) at org.eclipse.jdt.internal.ui.InitializeAfterLoadJob$RealJob.run(InitializeAfterLoadJob.java:36) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55) Caused by: org.xml.sax.SAXParseException: Content is not allowed in prolog. at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292) at org.eclipse.jdt.internal.corext.util.History.load(History.java:255) ... 6 more !SUBENTRY 1 org.eclipse.jdt.ui 4 4 2010-06-08 19:24:41.442 !MESSAGE Problems reading information from XML 'OpenTypeHistory.xml' !STACK 0 org.xml.sax.SAXParseException: Content is not allowed in prolog. at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292) at org.eclipse.jdt.internal.corext.util.History.load(History.java:255) at org.eclipse.jdt.internal.corext.util.History.load(History.java:166) at org.eclipse.jdt.internal.corext.util.OpenTypeHistory.<init>(OpenTypeHistory.java:199) at org.eclipse.jdt.internal.corext.util.OpenTypeHistory.getInstance(OpenTypeHistory.java:185) at org.eclipse.jdt.internal.ui.JavaPlugin.initializeAfterLoad(JavaPlugin.java:381) at org.eclipse.jdt.internal.ui.InitializeAfterLoadJob$RealJob.run(InitializeAfterLoadJob.java:36) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55) !ENTRY org.eclipse.jdt.ui 4 10001 2010-06-08 19:24:50.435 !MESSAGE Internal Error !STACK 1 org.eclipse.jdt.internal.ui.JavaUIException: Problems reading information from XML 'QualifiedTypeNameHistory.xml' at org.eclipse.jdt.internal.corext.util.History.createException(History.java:70) at org.eclipse.jdt.internal.corext.util.History.load(History.java:257) at org.eclipse.jdt.internal.corext.util.History.load(History.java:166) at org.eclipse.jdt.internal.corext.util.QualifiedTypeNameHistory.<init>(QualifiedTypeNameHistory.java:33) at org.eclipse.jdt.internal.corext.util.QualifiedTypeNameHistory.getDefault(QualifiedTypeNameHistory.java:26) at org.eclipse.jdt.internal.ui.JavaPlugin.stop(JavaPlugin.java:602) at org.eclipse.osgi.framework.internal.core.BundleContextImpl$2.run(BundleContextImpl.java:843) at java.security.AccessController.doPrivileged(Native Method) at org.eclipse.osgi.framework.internal.core.BundleContextImpl.stop(BundleContextImpl.java:836) at org.eclipse.osgi.framework.internal.core.BundleHost.stopWorker(BundleHost.java:474) at org.eclipse.osgi.framework.internal.core.AbstractBundle.suspend(AbstractBundle.java:546) at org.eclipse.osgi.framework.internal.core.Framework.suspendBundle(Framework.java:1098) at org.eclipse.osgi.framework.internal.core.StartLevelManager.decFWSL(StartLevelManager.java:593) at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:261) at org.eclipse.osgi.framework.internal.core.StartLevelManager.shutdown(StartLevelManager.java:216) at org.eclipse.osgi.framework.internal.core.InternalSystemBundle.suspend(InternalSystemBundle.java:266) at org.eclipse.osgi.framework.internal.core.Framework.shutdown(Framework.java:685) at org.eclipse.osgi.framework.internal.core.Framework.close(Framework.java:583) at org.eclipse.core.runtime.adaptor.EclipseStarter.shutdown(EclipseStarter.java:409) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:200) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:592) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:559) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:514) at org.eclipse.equinox.launcher.Main.run(Main.java:1311) Caused by: org.xml.sax.SAXParseException: Content is not allowed in prolog. at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292) at org.eclipse.jdt.internal.corext.util.History.load(History.java:255) ... 25 more !SUBENTRY 1 org.eclipse.jdt.ui 4 4 2010-06-08 19:24:50.435 !MESSAGE Problems reading information from XML 'QualifiedTypeNameHistory.xml' !STACK 0 org.xml.sax.SAXParseException: Content is not allowed in prolog. at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:264) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:292) at org.eclipse.jdt.internal.corext.util.History.load(History.java:255) at org.eclipse.jdt.internal.corext.util.History.load(History.java:166) at org.eclipse.jdt.internal.corext.util.QualifiedTypeNameHistory.<init>(QualifiedTypeNameHistory.java:33) at org.eclipse.jdt.internal.corext.util.QualifiedTypeNameHistory.getDefault(QualifiedTypeNameHistory.java:26) at org.eclipse.jdt.internal.ui.JavaPlugin.stop(JavaPlugin.java:602) at org.eclipse.osgi.framework.internal.core.BundleContextImpl$2.run(BundleContextImpl.java:843) at java.security.AccessController.doPrivileged(Native Method) at org.eclipse.osgi.framework.internal.core.BundleContextImpl.stop(BundleContextImpl.java:836) at org.eclipse.osgi.framework.internal.core.BundleHost.stopWorker(BundleHost.java:474) at org.eclipse.osgi.framework.internal.core.AbstractBundle.suspend(AbstractBundle.java:546) at org.eclipse.osgi.framework.internal.core.Framework.suspendBundle(Framework.java:1098) at org.eclipse.osgi.framework.internal.core.StartLevelManager.decFWSL(StartLevelManager.java:593) at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:261) at org.eclipse.osgi.framework.internal.core.StartLevelManager.shutdown(StartLevelManager.java:216) at org.eclipse.osgi.framework.internal.core.InternalSystemBundle.suspend(InternalSystemBundle.java:266) at org.eclipse.osgi.framework.internal.core.Framework.shutdown(Framework.java:685) at org.eclipse.osgi.framework.internal.core.Framework.close(Framework.java:583) at org.eclipse.core.runtime.adaptor.EclipseStarter.shutdown(EclipseStarter.java:409) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:200) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:592) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:559) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:514) at org.eclipse.equinox.launcher.Main.run(Main.java:1311)

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• DirectShow: Video-Preview and Image (with working code)

  - by xsl

  Questions / Issues If someone can recommend me a good free hosting site I can provide the whole project file. As mentioned in the text below the TakePicture() method is not working properly on the HTC HD 2 device. It would be nice if someone could look at the code below and tell me if it is right or wrong what I'm doing. Introduction I recently asked a question about displaying a video preview, taking camera image and rotating a video stream with DirectShow. The tricky thing about the topic is, that it's very hard to find good examples and the documentation and the framework itself is very hard to understand for someone who is new to windows programming and C++ in general. Nevertheless I managed to create a class that implements most of this features and probably works with most mobile devices. Probably because the DirectShow implementation depends a lot on the device itself. I could only test it with the HTC HD and HTC HD2, which are known as quite incompatible. HTC HD Working: Video preview, writing photo to file Not working: Set video resolution (CRASH), set photo resolution (LOW quality) HTC HD 2 Working: Set video resolution, set photo resolution Problematic: Video Preview rotated Not working: Writing photo to file To make it easier for others by providing a working example, I decided to share everything I have got so far below. I removed all of the error handling for the sake of simplicity. As far as documentation goes, I can recommend you to read the MSDN documentation, after that the code below is pretty straight forward. void Camera::Init() { CreateComObjects(); _captureGraphBuilder->SetFiltergraph(_filterGraph); InitializeVideoFilter(); InitializeStillImageFilter(); } Dipslay a video preview (working with any tested handheld): void Camera::DisplayVideoPreview(HWND windowHandle) { IVideoWindow *_vidWin; _filterGraph->QueryInterface(IID_IMediaControl,(void **) &_mediaControl); _filterGraph->QueryInterface(IID_IVideoWindow, (void **) &_vidWin); _videoCaptureFilter->QueryInterface(IID_IAMVideoControl, (void**) &_videoControl); _captureGraphBuilder->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, _videoCaptureFilter, NULL, NULL); CRect rect; long width, height; GetClientRect(windowHandle, &rect); _vidWin->put_Owner((OAHWND)windowHandle); _vidWin->put_WindowStyle(WS_CHILD | WS_CLIPSIBLINGS); _vidWin->get_Width(&width); _vidWin->get_Height(&height); height = rect.Height(); _vidWin->put_Height(height); _vidWin->put_Width(rect.Width()); _vidWin->SetWindowPosition(0,0, rect.Width(), height); _mediaControl->Run(); } HTC HD2: If set SetPhotoResolution() is called FindPin will return E_FAIL. If not, it will create a file full of null bytes. HTC HD: Works void Camera::TakePicture(WCHAR *fileName) { CComPtr<IFileSinkFilter> fileSink; CComPtr<IPin> stillPin; CComPtr<IUnknown> unknownCaptureFilter; CComPtr<IAMVideoControl> videoControl; _imageSinkFilter.QueryInterface(&fileSink); fileSink->SetFileName(fileName, NULL); _videoCaptureFilter.QueryInterface(&unknownCaptureFilter); _captureGraphBuilder->FindPin(unknownCaptureFilter, PINDIR_OUTPUT, &PIN_CATEGORY_STILL, &MEDIATYPE_Video, FALSE, 0, &stillPin); _videoCaptureFilter.QueryInterface(&videoControl); videoControl->SetMode(stillPin, VideoControlFlag_Trigger); } Set resolution: Works great on HTC HD2. HTC HD won't allow SetVideoResolution() and only offers one low resolution photo resolution: void Camera::SetVideoResolution(int width, int height) { SetResolution(true, width, height); } void Camera::SetPhotoResolution(int width, int height) { SetResolution(false, width, height); } void Camera::SetResolution(bool video, int width, int height) { IAMStreamConfig *config; config = NULL; if (video) { _captureGraphBuilder->FindInterface(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, _videoCaptureFilter, IID_IAMStreamConfig, (void**) &config); } else { _captureGraphBuilder->FindInterface(&PIN_CATEGORY_STILL, &MEDIATYPE_Video, _videoCaptureFilter, IID_IAMStreamConfig, (void**) &config); } int resolutions, size; VIDEO_STREAM_CONFIG_CAPS caps; config->GetNumberOfCapabilities(&resolutions, &size); for (int i = 0; i < resolutions; i++) { AM_MEDIA_TYPE *mediaType; if (config->GetStreamCaps(i, &mediaType, reinterpret_cast<BYTE*>(&caps)) == S_OK ) { int maxWidth = caps.MaxOutputSize.cx; int maxHeigth = caps.MaxOutputSize.cy; if(maxWidth == width && maxHeigth == height) { VIDEOINFOHEADER *info = reinterpret_cast<VIDEOINFOHEADER*>(mediaType->pbFormat); info->bmiHeader.biWidth = maxWidth; info->bmiHeader.biHeight = maxHeigth; info->bmiHeader.biSizeImage = DIBSIZE(info->bmiHeader); config->SetFormat(mediaType); DeleteMediaType(mediaType); break; } DeleteMediaType(mediaType); } } } Other methods used to build the filter graph and create the COM objects: void Camera::CreateComObjects() { CoInitialize(NULL); CoCreateInstance(CLSID_CaptureGraphBuilder, NULL, CLSCTX_INPROC_SERVER, IID_ICaptureGraphBuilder2, (void **) &_captureGraphBuilder); CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, IID_IGraphBuilder, (void **) &_filterGraph); CoCreateInstance(CLSID_VideoCapture, NULL, CLSCTX_INPROC, IID_IBaseFilter, (void**) &_videoCaptureFilter); CoCreateInstance(CLSID_IMGSinkFilter, NULL, CLSCTX_INPROC, IID_IBaseFilter, (void**) &_imageSinkFilter); } void Camera::InitializeVideoFilter() { _videoCaptureFilter->QueryInterface(&_propertyBag); wchar_t deviceName[MAX_PATH] = L"\0"; GetDeviceName(deviceName); CComVariant comName = deviceName; CPropertyBag propertyBag; propertyBag.Write(L"VCapName", &comName); _propertyBag->Load(&propertyBag, NULL); _filterGraph->AddFilter(_videoCaptureFilter, L"Video Capture Filter Source"); } void Camera::InitializeStillImageFilter() { _filterGraph->AddFilter(_imageSinkFilter, L"Still image filter"); _captureGraphBuilder->RenderStream(&PIN_CATEGORY_STILL, &MEDIATYPE_Video, _videoCaptureFilter, NULL, _imageSinkFilter); } void Camera::GetDeviceName(WCHAR *deviceName) { HRESULT hr = S_OK; HANDLE handle = NULL; DEVMGR_DEVICE_INFORMATION di; GUID guidCamera = { 0xCB998A05, 0x122C, 0x4166, 0x84, 0x6A, 0x93, 0x3E, 0x4D, 0x7E, 0x3C, 0x86 }; di.dwSize = sizeof(di); handle = FindFirstDevice(DeviceSearchByGuid, &guidCamera, &di); StringCchCopy(deviceName, MAX_PATH, di.szLegacyName); } Full header file: #ifndef __CAMERA_H__ #define __CAMERA_H__ class Camera { public: void Init(); void DisplayVideoPreview(HWND windowHandle); void TakePicture(WCHAR *fileName); void SetVideoResolution(int width, int height); void SetPhotoResolution(int width, int height); private: CComPtr<ICaptureGraphBuilder2> _captureGraphBuilder; CComPtr<IGraphBuilder> _filterGraph; CComPtr<IBaseFilter> _videoCaptureFilter; CComPtr<IPersistPropertyBag> _propertyBag; CComPtr<IMediaControl> _mediaControl; CComPtr<IAMVideoControl> _videoControl; CComPtr<IBaseFilter> _imageSinkFilter; void GetDeviceName(WCHAR *deviceName); void InitializeVideoFilter(); void InitializeStillImageFilter(); void CreateComObjects(); void SetResolution(bool video, int width, int height); }; #endif

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• Understanding Request Validation in ASP.NET MVC 3

  - by imran_ku07

       Introduction:             A fact that you must always remember "never ever trust user inputs". An application that trusts user inputs may be easily vulnerable to XSS, XSRF, SQL Injection, etc attacks. XSS and XSRF are very dangerous attacks. So to mitigate these attacks ASP.NET introduced request validation in ASP.NET 1.1. During request validation, ASP.NET will throw HttpRequestValidationException: 'A potentially dangerous XXX value was detected from the client', if he found, < followed by an exclamation(like <!) or < followed by the letters a through z(like <s) or & followed by a pound sign(like &#123) as a part of query string, posted form and cookie collection. In ASP.NET 4.0, request validation becomes extensible. This means that you can extend request validation. Also in ASP.NET 4.0, by default request validation is enabled before the BeginRequest phase of an HTTP request. ASP.NET MVC 3 moves one step further by making request validation granular. This allows you to disable request validation for some properties of a model while maintaining request validation for all other cases. In this article I will show you the use of request validation in ASP.NET MVC 3. Then I will briefly explain the internal working of granular request validation.       Description:             First of all create a new ASP.NET MVC 3 application. Then create a simple model class called MyModel,     public class MyModel { public string Prop1 { get; set; } public string Prop2 { get; set; } }             Then just update the index action method as follows,   public ActionResult Index(MyModel p) { return View(); }             Now just run this application. You will find that everything works just fine. Now just append this query string ?Prop1=<s to the url of this application, you will get the HttpRequestValidationException exception.           Now just decorate the Index action method with [ValidateInputAttribute(false)],   [ValidateInput(false)] public ActionResult Index(MyModel p) { return View(); }             Run this application again with same query string. You will find that your application run without any unhandled exception.           Up to now, there is nothing new in ASP.NET MVC 3 because ValidateInputAttribute was present in the previous versions of ASP.NET MVC. Any problem with this approach? Yes there is a problem with this approach. The problem is that now users can send html for both Prop1 and Prop2 properties and a lot of developers are not aware of it. This means that now everyone can send html with both parameters(e.g, ?Prop1=<s&Prop2=<s). So ValidateInput attribute does not gives you the guarantee that your application is safe to XSS or XSRF. This is the reason why ASP.NET MVC team introduced granular request validation in ASP.NET MVC 3. Let's see this feature.           Remove [ValidateInputAttribute(false)] on Index action and update MyModel class as follows,   public class MyModel { [AllowHtml] public string Prop1 { get; set; } public string Prop2 { get; set; } }             Note that AllowHtml attribute is only decorated on Prop1 property. Run this application again with ?Prop1=<s query string. You will find that your application run just fine. Run this application again with ?Prop1=<s&Prop2=<s query string, you will get HttpRequestValidationException exception. This shows that the granular request validation in ASP.NET MVC 3 only allows users to send html for properties decorated with AllowHtml attribute.            Sometimes you may need to access Request.QueryString or Request.Form directly. You may change your code as follows,   [ValidateInput(false)] public ActionResult Index() { var prop1 = Request.QueryString["Prop1"]; return View(); }             Run this application again, you will get the HttpRequestValidationException exception again even you have [ValidateInput(false)] on your Index action. The reason is that Request flags are still not set to unvalidate. I will explain this later. For making this work you need to use Unvalidated extension method,     public ActionResult Index() { var q = Request.Unvalidated().QueryString; var prop1 = q["Prop1"]; return View(); }             Unvalidated extension method is defined in System.Web.Helpers namespace . So you need to add using System.Web.Helpers; in this class file. Run this application again, your application run just fine.             There you have it. If you are not curious to know the internal working of granular request validation then you can skip next paragraphs completely. If you are interested then carry on reading.             Create a new ASP.NET MVC 2 application, then open global.asax.cs file and the following lines,     protected void Application_BeginRequest() { var q = Request.QueryString; }             Then make the Index action method as,    [ValidateInput(false)] public ActionResult Index(string id) { return View(); }             Please note that the Index action method contains a parameter and this action method is decorated with [ValidateInput(false)]. Run this application again, but now with ?id=<s query string, you will get HttpRequestValidationException exception at Application_BeginRequest method. Now just add the following entry in web.config,   <httpRuntime requestValidationMode="2.0"/>             Now run this application again. This time your application will run just fine. Now just see the following quote from ASP.NET 4 Breaking Changes,   In ASP.NET 4, by default, request validation is enabled for all requests, because it is enabled before the BeginRequest phase of an HTTP request. As a result, request validation applies to requests for all ASP.NET resources, not just .aspx page requests. This includes requests such as Web service calls and custom HTTP handlers. Request validation is also active when custom HTTP modules are reading the contents of an HTTP request.             This clearly state that request validation is enabled before the BeginRequest phase of an HTTP request. For understanding what does enabled means here, we need to see HttpRequest.ValidateInput, HttpRequest.QueryString and HttpRequest.Form methods/properties in System.Web assembly. Here is the implementation of HttpRequest.ValidateInput, HttpRequest.QueryString and HttpRequest.Form methods/properties in System.Web assembly,     public NameValueCollection Form { get { if (this._form == null) { this._form = new HttpValueCollection(); if (this._wr != null) { this.FillInFormCollection(); } this._form.MakeReadOnly(); } if (this._flags[2]) { this._flags.Clear(2); this.ValidateNameValueCollection(this._form, RequestValidationSource.Form); } return this._form; } } public NameValueCollection QueryString { get { if (this._queryString == null) { this._queryString = new HttpValueCollection(); if (this._wr != null) { this.FillInQueryStringCollection(); } this._queryString.MakeReadOnly(); } if (this._flags[1]) { this._flags.Clear(1); this.ValidateNameValueCollection(this._queryString, RequestValidationSource.QueryString); } return this._queryString; } } public void ValidateInput() { if (!this._flags[0x8000]) { this._flags.Set(0x8000); this._flags.Set(1); this._flags.Set(2); this._flags.Set(4); this._flags.Set(0x40); this._flags.Set(0x80); this._flags.Set(0x100); this._flags.Set(0x200); this._flags.Set(8); } }             The above code indicates that HttpRequest.QueryString and HttpRequest.Form will only validate the querystring and form collection if certain flags are set. These flags are automatically set if you call HttpRequest.ValidateInput method. Now run the above application again(don't forget to append ?id=<s query string in the url) with the same settings(i.e, requestValidationMode="2.0" setting in web.config and Application_BeginRequest method in global.asax.cs), your application will run just fine. Now just update the Application_BeginRequest method as,   protected void Application_BeginRequest() { Request.ValidateInput(); var q = Request.QueryString; }             Note that I am calling Request.ValidateInput method prior to use Request.QueryString property. ValidateInput method will internally set certain flags(discussed above). These flags will then tells the Request.QueryString (and Request.Form) property that validate the query string(or form) when user call Request.QueryString(or Request.Form) property. So running this application again with ?id=<s query string will throw HttpRequestValidationException exception. Now I hope it is clear to you that what does requestValidationMode do. It just tells the ASP.NET that not invoke the Request.ValidateInput method internally before the BeginRequest phase of an HTTP request if requestValidationMode is set to a value less than 4.0 in web.config. Here is the implementation of HttpRequest.ValidateInputIfRequiredByConfig method which will prove this statement(Don't be confused with HttpRequest and Request. Request is the property of HttpRequest class),    internal void ValidateInputIfRequiredByConfig() { ............................................................... ............................................................... ............................................................... ............................................................... if (httpRuntime.RequestValidationMode >= VersionUtil.Framework40) { this.ValidateInput(); } }              Hopefully the above discussion will clear you how requestValidationMode works in ASP.NET 4. It is also interesting to note that both HttpRequest.QueryString and HttpRequest.Form only throws the exception when you access them first time. Any subsequent access to HttpRequest.QueryString and HttpRequest.Form will not throw any exception. Continuing with the above example, just update Application_BeginRequest method in global.asax.cs file as,   protected void Application_BeginRequest() { try { var q = Request.QueryString; var f = Request.Form; } catch//swallow this exception { } var q1 = Request.QueryString; var f1 = Request.Form; }             Without setting requestValidationMode to 2.0 and without decorating ValidateInput attribute on Index action, your application will work just fine because both HttpRequest.QueryString and HttpRequest.Form will clear their flags after reading HttpRequest.QueryString and HttpRequest.Form for the first time(see the implementation of HttpRequest.QueryString and HttpRequest.Form above).           Now let's see ASP.NET MVC 3 granular request validation internal working. First of all we need to see type of HttpRequest.QueryString and HttpRequest.Form properties. Both HttpRequest.QueryString and HttpRequest.Form properties are of type NameValueCollection which is inherited from the NameObjectCollectionBase class. NameObjectCollectionBase class contains _entriesArray, _entriesTable, NameObjectEntry.Key and NameObjectEntry.Value fields which granular request validation uses internally. In addition granular request validation also uses _queryString, _form and _flags fields, ValidateString method and the Indexer of HttpRequest class. Let's see when and how granular request validation uses these fields.           Create a new ASP.NET MVC 3 application. Then put a breakpoint at Application_BeginRequest method and another breakpoint at HomeController.Index method. Now just run this application. When the break point inside Application_BeginRequest method hits then add the following expression in quick watch window, System.Web.HttpContext.Current.Request.QueryString. You will see the following screen,                                              Now Press F5 so that the second breakpoint inside HomeController.Index method hits. When the second breakpoint hits then add the following expression in quick watch window again, System.Web.HttpContext.Current.Request.QueryString. You will see the following screen,                            First screen shows that _entriesTable field is of type System.Collections.Hashtable and _entriesArray field is of type System.Collections.ArrayList during the BeginRequest phase of the HTTP request. While the second screen shows that _entriesTable type is changed to Microsoft.Web.Infrastructure.DynamicValidationHelper.LazilyValidatingHashtable and _entriesArray type is changed to Microsoft.Web.Infrastructure.DynamicValidationHelper.LazilyValidatingArrayList during executing the Index action method. In addition to these members, ASP.NET MVC 3 also perform some operation on _flags, _form, _queryString and other members of HttpRuntime class internally. This shows that ASP.NET MVC 3 performing some operation on the members of HttpRequest class for making granular request validation possible.           Both LazilyValidatingArrayList and LazilyValidatingHashtable classes are defined in the Microsoft.Web.Infrastructure assembly. You may wonder why their name starts with Lazily. The fact is that now with ASP.NET MVC 3, request validation will be performed lazily. In simple words, Microsoft.Web.Infrastructure assembly is now taking the responsibility for request validation from System.Web assembly. See the below screens. The first screen depicting HttpRequestValidationException exception in ASP.NET MVC 2 application while the second screen showing HttpRequestValidationException exception in ASP.NET MVC 3 application.   In MVC 2:                 In MVC 3:                          The stack trace of the second screenshot shows that Microsoft.Web.Infrastructure assembly (instead of System.Web assembly) is now performing request validation in ASP.NET MVC 3. Now you may ask: where Microsoft.Web.Infrastructure assembly is performing some operation on the members of HttpRequest class. There are at least two places where the Microsoft.Web.Infrastructure assembly performing some operation , Microsoft.Web.Infrastructure.DynamicValidationHelper.GranularValidationReflectionUtil.GetInstance method and Microsoft.Web.Infrastructure.DynamicValidationHelper.ValidationUtility.CollectionReplacer.ReplaceCollection method, Here is the implementation of these methods,   private static GranularValidationReflectionUtil GetInstance() { try { if (DynamicValidationShimReflectionUtil.Instance != null) { return null; } GranularValidationReflectionUtil util = new GranularValidationReflectionUtil(); Type containingType = typeof(NameObjectCollectionBase); string fieldName = "_entriesArray"; bool isStatic = false; Type fieldType = typeof(ArrayList); FieldInfo fieldInfo = CommonReflectionUtil.FindField(containingType, fieldName, isStatic, fieldType); util._del_get_NameObjectCollectionBase_entriesArray = MakeFieldGetterFunc<NameObjectCollectionBase, ArrayList>(fieldInfo); util._del_set_NameObjectCollectionBase_entriesArray = MakeFieldSetterFunc<NameObjectCollectionBase, ArrayList>(fieldInfo); Type type6 = typeof(NameObjectCollectionBase); string str2 = "_entriesTable"; bool flag2 = false; Type type7 = typeof(Hashtable); FieldInfo info2 = CommonReflectionUtil.FindField(type6, str2, flag2, type7); util._del_get_NameObjectCollectionBase_entriesTable = MakeFieldGetterFunc<NameObjectCollectionBase, Hashtable>(info2); util._del_set_NameObjectCollectionBase_entriesTable = MakeFieldSetterFunc<NameObjectCollectionBase, Hashtable>(info2); Type targetType = CommonAssemblies.System.GetType("System.Collections.Specialized.NameObjectCollectionBase+NameObjectEntry"); Type type8 = targetType; string str3 = "Key"; bool flag3 = false; Type type9 = typeof(string); FieldInfo info3 = CommonReflectionUtil.FindField(type8, str3, flag3, type9); util._del_get_NameObjectEntry_Key = MakeFieldGetterFunc<string>(targetType, info3); Type type10 = targetType; string str4 = "Value"; bool flag4 = false; Type type11 = typeof(object); FieldInfo info4 = CommonReflectionUtil.FindField(type10, str4, flag4, type11); util._del_get_NameObjectEntry_Value = MakeFieldGetterFunc<object>(targetType, info4); util._del_set_NameObjectEntry_Value = MakeFieldSetterFunc(targetType, info4); Type type12 = typeof(HttpRequest); string methodName = "ValidateString"; bool flag5 = false; Type[] argumentTypes = new Type[] { typeof(string), typeof(string), typeof(RequestValidationSource) }; Type returnType = typeof(void); MethodInfo methodInfo = CommonReflectionUtil.FindMethod(type12, methodName, flag5, argumentTypes, returnType); util._del_validateStringCallback = CommonReflectionUtil.MakeFastCreateDelegate<HttpRequest, ValidateStringCallback>(methodInfo); Type type = CommonAssemblies.SystemWeb.GetType("System.Web.HttpValueCollection"); util._del_HttpValueCollection_ctor = CommonReflectionUtil.MakeFastNewObject<Func<NameValueCollection>>(type); Type type14 = typeof(HttpRequest); string str6 = "_form"; bool flag6 = false; Type type15 = type; FieldInfo info6 = CommonReflectionUtil.FindField(type14, str6, flag6, type15); util._del_get_HttpRequest_form = MakeFieldGetterFunc<HttpRequest, NameValueCollection>(info6); util._del_set_HttpRequest_form = MakeFieldSetterFunc(typeof(HttpRequest), info6); Type type16 = typeof(HttpRequest); string str7 = "_queryString"; bool flag7 = false; Type type17 = type; FieldInfo info7 = CommonReflectionUtil.FindField(type16, str7, flag7, type17); util._del_get_HttpRequest_queryString = MakeFieldGetterFunc<HttpRequest, NameValueCollection>(info7); util._del_set_HttpRequest_queryString = MakeFieldSetterFunc(typeof(HttpRequest), info7); Type type3 = CommonAssemblies.SystemWeb.GetType("System.Web.Util.SimpleBitVector32"); Type type18 = typeof(HttpRequest); string str8 = "_flags"; bool flag8 = false; Type type19 = type3; FieldInfo flagsFieldInfo = CommonReflectionUtil.FindField(type18, str8, flag8, type19); Type type20 = type3; string str9 = "get_Item"; bool flag9 = false; Type[] typeArray4 = new Type[] { typeof(int) }; Type type21 = typeof(bool); MethodInfo itemGetter = CommonReflectionUtil.FindMethod(type20, str9, flag9, typeArray4, type21); Type type22 = type3; string str10 = "set_Item"; bool flag10 = false; Type[] typeArray6 = new Type[] { typeof(int), typeof(bool) }; Type type23 = typeof(void); MethodInfo itemSetter = CommonReflectionUtil.FindMethod(type22, str10, flag10, typeArray6, type23); MakeRequestValidationFlagsAccessors(flagsFieldInfo, itemGetter, itemSetter, out util._del_BitVector32_get_Item, out util._del_BitVector32_set_Item); return util; } catch { return null; } } private static void ReplaceCollection(HttpContext context, FieldAccessor<NameValueCollection> fieldAccessor, Func<NameValueCollection> propertyAccessor, Action<NameValueCollection> storeInUnvalidatedCollection, RequestValidationSource validationSource, ValidationSourceFlag validationSourceFlag) { NameValueCollection originalBackingCollection; ValidateStringCallback validateString; SimpleValidateStringCallback simpleValidateString; Func<NameValueCollection> getActualCollection; Action<NameValueCollection> makeCollectionLazy; HttpRequest request = context.Request; Func<bool> getValidationFlag = delegate { return _reflectionUtil.GetRequestValidationFlag(request, validationSourceFlag); }; Func<bool> func = delegate { return !getValidationFlag(); }; Action<bool> setValidationFlag = delegate (bool value) { _reflectionUtil.SetRequestValidationFlag(request, validationSourceFlag, value); }; if ((fieldAccessor.Value != null) && func()) { storeInUnvalidatedCollection(fieldAccessor.Value); } else { originalBackingCollection = fieldAccessor.Value; validateString = _reflectionUtil.MakeValidateStringCallback(context.Request); simpleValidateString = delegate (string value, string key) { if (((key == null) || !key.StartsWith("__", StringComparison.Ordinal)) && !string.IsNullOrEmpty(value)) { validateString(value, key, validationSource); } }; getActualCollection = delegate { fieldAccessor.Value = originalBackingCollection; bool flag = getValidationFlag(); setValidationFlag(false); NameValueCollection col = propertyAccessor(); setValidationFlag(flag); storeInUnvalidatedCollection(new NameValueCollection(col)); return col; }; makeCollectionLazy = delegate (NameValueCollection col) { simpleValidateString(col[null], null); LazilyValidatingArrayList array = new LazilyValidatingArrayList(_reflectionUtil.GetNameObjectCollectionEntriesArray(col), simpleValidateString); _reflectionUtil.SetNameObjectCollectionEntriesArray(col, array); LazilyValidatingHashtable table = new LazilyValidatingHashtable(_reflectionUtil.GetNameObjectCollectionEntriesTable(col), simpleValidateString); _reflectionUtil.SetNameObjectCollectionEntriesTable(col, table); }; Func<bool> hasValidationFired = func; Action disableValidation = delegate { setValidationFlag(false); }; Func<int> fillInActualFormContents = delegate { NameValueCollection values = getActualCollection(); makeCollectionLazy(values); return values.Count; }; DeferredCountArrayList list = new DeferredCountArrayList(hasValidationFired, disableValidation, fillInActualFormContents); NameValueCollection target = _reflectionUtil.NewHttpValueCollection(); _reflectionUtil.SetNameObjectCollectionEntriesArray(target, list); fieldAccessor.Value = target; } }             Hopefully the above code will help you to understand the internal working of granular request validation. It is also important to note that Microsoft.Web.Infrastructure assembly invokes HttpRequest.ValidateInput method internally. For further understanding please see Microsoft.Web.Infrastructure assembly code. Finally you may ask: at which stage ASP NET MVC 3 will invoke these methods. You will find this answer by looking at the following method source,   Unvalidated extension method for HttpRequest class defined in System.Web.Helpers.Validation class. System.Web.Mvc.MvcHandler.ProcessRequestInit method. System.Web.Mvc.ControllerActionInvoker.ValidateRequest method. System.Web.WebPages.WebPageHttpHandler.ProcessRequestInternal method.       Summary:             ASP.NET helps in preventing XSS attack using a feature called request validation. In this article, I showed you how you can use granular request validation in ASP.NET MVC 3. I explain you the internal working of  granular request validation. Hope you will enjoy this article too.   SyntaxHighlighter.all()

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• Windows CE Chat Transcript (March 30, 2010)

  - by Bruce Eitman

  For those of you who missed the chat today, here is the raw transcript.   By raw, I mean that I copied and pasted the discussion without any edits. This is divided into two parts, the top part is the answers from the Microsoft Experts and the bottom part is the questions from the audience. Answers from Microsoft:   Karel Danihelka [MS] (Expert)[2010-3-30 12:2]: Hi everyone, my name is Karel Danihelka and I am developer in partner response team. Sing Wee [MS] (Expert)[2010-3-30 12:2]: Hi, I'm Sing Wee, part of the CoreOS/BSP Test Team. GLanger_MS (Expert)[2010-3-30 12:2]: Hi, I'm Glen Langer, program manager on the Core Team. Karel Danihelka [MS] (Expert)[2010-3-30 12:3]: Q: I need to implement hardware timers on my windows CE 6.0 device to trigger events at microsecond intervals. Where should i start? A: Until you are using CPU with GHz frequency your only chance is use interrupt handler and implement all funcionality there. But it will be really tricky and may reduce system performance. If period will be near to millisecond timeframe you can use normal thread wait for event pattern. Karel Danihelka [MS] (Expert)[2010-3-30 12:5]: Q: I want to partition my NAND Flash device. One partition to use for hive ragistry and the other for the apps and data. The only way to do it is programmatically or setting some registry values ? A: It need to be set in registry - generally you need mark this partition as boot partition. Karel Danihelka [MS] (Expert)[2010-3-30 12:7]: Q: My CPU is Intel celeron M processor 1Ghz. A: In this case you can try use normal approach - in interrupt handler return SYSINTR and start thread in device driver which will spin thread waiting on event attached to this SYSINTR. Karel Danihelka [MS] (Expert)[2010-3-30 12:7]: Q: If i need to implement it using interrupt handlers, What are all the files that I should look at? A: Good quesiton - I would recommend documentation and there was BSP development book to download for free. mikehall_ms (Moderator)[2010-3-30 12:8]: Q: Hi guys, what's the formal way to report bugs back to the core team / product team? The mechanism of calling the support phone number every time is really onerous and time-consuming. Is there another mechanism? A: Using product support is the formal way to report bugs/issues - Product support can then create an issue that can be tracked. Karel Danihelka [MS] (Expert)[2010-3-30 12:9]: Q: But the operation for creating the partitions ? A: This is tricky - if you will make it autopartition & autoformat it will be created by filesystem. But generally it depends on your boot loader. mikehall_ms (Moderator)[2010-3-30 12:10]: Q: Is Windows Phone 7 related to Windows CE? If so, can you tell me what version of Windows CE is the basis? Is it in fact the new version of Windows Mobile? A: At MIX 2010 Charlie Kindel presented a session that described some of the core technologies that make up Windows Phone 7 Series, including the underlying operating system (Windows CE) and the new ISV programming model based on Silverlight and .NET - check out the Mix Online Videos to get more information. davbo-msft (Moderator)[2010-3-30 12:10]: Q: Is Windows Phone 7 related to Windows CE? If so, can you tell me what version of Windows CE is the basis? Is it in fact the new version of Windows Mobile? A: This forum is to discussed released products in the industry. Windows Mobile & Windows CE are based on the same Windows CE Kernel/system. Windows CE is focused on deliverying the OS for embedded customers in the market where Windows Mobile is focused on deliverying compelling Windows Phone platform. davbo-msft (Moderator)[2010-3-30 12:11]: Q: Is Windows Phone 7 related to Windows CE? If so, can you tell me what version of Windows CE is the basis? Is it in fact the new version of Windows Mobile? A: http://en.wikipedia.org/wiki/Windows_CE Wikipedia gives a good breakdown of the version history. Travis Hobrla [MS] (Expert)[2010-3-30 12:13]: Q: I created a OS design with KITL and kernel debugger enabled. But I am unable to connect to the target for debugging. I am getting the following error when i try to connect with the device. PB Debugger Cannot initialize the Kernel Debugger. PB Debugger Debugger could not initialize connection. PB Debugger The Kernel Debugger is waiting to connect with target. PB Debugger The Kernel Debugger has been disconnected successfully. A: One possibility is that a rogue cesvchost.exe has co-opted the debugger. I am assuming this is CE 6.0? Can you try exiting visual studio and manually killing the cesvchost.exe process from the Task Manager? davbo-msft (Moderator)[2010-3-30 12:14]: Q: Hi guys, what's the formal way to report bugs back to the core team / product team? The mechanism of calling the support phone number every time is really onerous and time-consuming. Is there another mechanism? A: For info on contacting Microsoft support refer to the support page on the Embedded website: http://msdn.microsoft.com/en-us/windowsembedded/dd897633.aspx Sing Wee [MS] (Expert)[2010-3-30 12:16]: Q: Do u mean ISR/IST implementation? How can i register an interrupt? What kind of interrupt should i register? A: A good introduction to interrupts in WinCE 6.0 can be found here (aside from the documentation on MSDN): http://download.microsoft.com/download/9/c/f/9cffaa58-4000-48d6-a4b2-5fed9e4e6410/Chapter%206%20-%20Developing%20Device%20Drivers.pdf mikehall_ms (Moderator)[2010-3-30 12:16]: Q: What will be different in Windows Compact 7 from CE 6.0? A: Unfortunately we cannot discuss unreleased products on this chat - keep an eye on the Windows Embedded web site and blogs to keep up to date with product announcements. Travis Hobrla [MS] (Expert)[2010-3-30 12:16]: Q: I am using CE 6.0. There is no cesvchost process running in my system. A: What operating system are you using? Karel Danihelka [MS] (Expert)[2010-3-30 12:16]: Q: So...I have to modify file system code to create 2 partition at system startup ?!! I haven't understood.... A: You don't need to modify code, there are registry settings to achive this (look to documentation). But you may need to create partition table in boot loader. Unfortunatelly there isn't simple way how to do it. davbo-msft (Moderator)[2010-3-30 12:18]: Q: I would like to get a handle to a Silverlight screen section, is that possiable? A: Windows Embedded CE 6.0 R3 includes Sliverlight for Windows Embedded. Refer to New Features overview on the embedded web site. http://www.microsoft.com/windowsembedded/en-us/products/windowsce/default.mspx. Silverlight - The power of Silverlight brought to Windows Embedded CE to create rich applications and user interfaces is new part of Windows CE Embedded. mikehall_ms (Moderator)[2010-3-30 12:20]: Q: The link for developing device drivers is not working. can u please check that? A: http://msdn.microsoft.com/en-us/library/ms923714.aspx davbo-msft (Moderator)[2010-3-30 12:20]: Q: I would like to get a handle to a Silverlight screen section, is that possiable? A: Sorry misunderstood the question I thought you were asking if embedded CE could handle Silverlight. Please repost so that the question goes back into the active queue because once answered no way to put the status back to open. Travis Hobrla [MS] (Expert)[2010-3-30 12:21]: Q: sorry! Windows XP SP3 A: Can you try exiting VS2005 and confirming cesvchost.exe is not running, then renaming C:\Documents and Settings\USERNAME\Local Settings\Application Data\Microsoft\CoreCon\1.0 to 1.0_backup, then restarting VS2005? Sing Wee [MS] (Expert)[2010-3-30 12:24]: Q: Can I have the book's name please? A: I believe the downloadable version is related to the last link I sent. If you go to the following website, I believe you can download the whole thing: http://msdn.microsoft.com/en-us/windowsembedded/ce/cc294468.aspx davbo-msft (Moderator)[2010-3-30 12:24]: Q: If one has an image on a Silverlight page, it seems to be cached. How would one refresh that cache after changing the underlying image? A: change the URI of the image or use a writeable bitmap if they want to manually toggle the pixels Sing Wee [MS] (Expert)[2010-3-30 12:25]: A: Whoops, hit [ENTER] too early. On the right side, you'll see there an "Exam Preparation Kit" link that can be downloaded in several different languages. Sing Wee [MS] (Expert)[2010-3-30 12:25]: Q: Can I have the book's name please? A: Whoops, hit [ENTER] too early. On the right side, you'll see there an "Exam Preparation Kit" link that can be downloaded in several different languages. Karel Danihelka [MS] (Expert)[2010-3-30 12:26]: Q: I have a NAND Flash on my target device. On this flash I have the hive registry and an application.I have observed that when the NAND flash is fully, the system startup time is longer....is there a degradation of NAND use that influences the startup time ? Why ? A: Yes - on boot flash abstraction library (old one) read metadata from all sectors to rebuild physical - logical mapping table. davbo-msft (Moderator)[2010-3-30 12:27]: Q: I would like to get a handle to a Silverlight screen section, is that possiable? A: Need addition info on this question. Can you provide more details on what you are trying to do in Silverlight? davbo-msft (Moderator)[2010-3-30 12:27]: Q: If one has an image on a Silverlight page, it seems to be cached. How would one refresh that cache after changing the underlying image? A: Additonal Info: if you want to manually touch the pixels use WriteableBitmap if you want to use the underlying HWND then use IXRVisualHost::GetHWND() davbo-msft (Moderator)[2010-3-30 12:28]: Q: Writable bitmap, is there an example of the syntax? A: if you want to manually touch the pixels use WriteableBitmap if you want to use the underlying HWND then use IXRVisualHost::GetHWND() davbo-msft (Moderator)[2010-3-30 12:29]: Q: I would like to get a handle to a Silverlight screen section, is that possiable? A: Can I get more information about this question about what you are trying to accomplish in Silverlight? davbo-msft (Moderator)[2010-3-30 12:31]: Q: IXRVisualHost::GetHWND() exactly what I needed Thanks, A: Your welcome Sing Wee [MS] (Expert)[2010-3-30 12:31]: Q: ok. thanks for the book's link A: No problem. Travis Hobrla [MS] (Expert)[2010-3-30 12:32]: Q: Typically for SoC devices you name your hardware specific libraries in the form "SOCDIRNAME_LIBNAME". In our platform "OMAP35XX_TPS659XX_TI_V1" if you do this we cause the catalog parser to die... For example if we have a library "Musbfn_OMAP35XX_TPS659XX_TI_V1.dll" entering this in the catalogs pbcxml file in a <module> section causes the XML parser to fail with : Error 3 The 'urn:Microsoft.PlatformBuilder/Catalog:Module' element is        invalid - The value '012345678901234567890123456789.dll' is invalid         according to its datatype         'urn:Microsoft.PlatformBuilder/Catalog:CatalogFileName' - The actual         length is greater than the MaxLength value. A: There are a couple workarounds I can think of. I believe the Module element is only used when doing SYSGEN parsing to make sure dependent SYSGENs are present when the item is selected, so I believe it is optional to the catalog. The other obvious workaround is to shorten the soc name. I realize neither of these solutions is ideal. This is not something we anticipated when we tested CE6.0, sorry. Travis Hobrla [MS] (Expert)[2010-3-30 12:33]: Q: I am getting this error only when I select the KdStub as the debugger in Target device connectivity. A: Right, but KdStub is the debugger that you should use. Have you tried the steps I suggested? Travis Hobrla [MS] (Expert)[2010-3-30 12:36]: Q: If I select Active KTIL, My OS doesn't boots. It says "loading NK.EXE at 0x<xxxxx> location" after that nothing comes in the debug log. A: Can you look at the serial debug output and see what is happening there? Often it can give you a clue to the KITL driver malfunctioning. Travis Hobrla [MS] (Expert)[2010-3-30 12:38]: Q: I have tried that and I am getting the same error. A: I am assuming you have a device created in Target -> Connectivity Options in Platform Builder. What are the Kernel download / Kernel transport for your device? Travis Hobrla [MS] (Expert)[2010-3-30 12:40]: Q: KITL: *** Device Name CEPC56059 *** WARN: KITL will run in polling mode VBridge:: built on [Jul 10 2009] time [10:20:14] VBridgeInit()...TX = [16384] bytes -- Rx = [16384] bytes Tx buffer [0xA1B84860] to [0xA1B88860]. Rx buffer [0xA1B88880] to [0xA1B8C880]. VBridge:: NK add MAC: [0-60-65-2-DA-FB] Connecting to Desktop KITL: Connected host IP: 1 Port: 1086 .. this is the output of the serial debug A: This looks reasonable and does not give clues as to why boot would halt at that point. If you capture a network trace or turn on KITL debug zones via dpCurSettings in kitl.dll, do you see KITL active after this? Travis Hobrla [MS] (Expert)[2010-3-30 12:41]: Q: Both is happening via Ethernet. A: Only thing I have left to suggest is a Platform Builder installation Repair, then. Karel Danihelka [MS] (Expert)[2010-3-30 12:42]: Q: Hi, I saw that the ATADISK is quite generic and des not have any optimizations. Do you have any advice to consider while tryin to improve the performance of it? A: If I remember correctly sample code has support for some specific hardware controllers (little obsolete now). This should be good start point (if you will not decide take existing driver as sample and write you own). Travis Hobrla [MS] (Expert)[2010-3-30 12:44]: Q: I didn't do that. I have to try. A: I think that's the next valid step. You need to figure out whether KITL is hanging or the device - use instrumented serial debug messages and network trace to determine this. Sing Wee [MS] (Expert)[2010-3-30 12:46]: Q: KITL: *** Device Name CEPC56059 *** WARN: KITL will run in polling mode VBridge:: built on [Jul 10 2009] time [10:20:14] VBridgeInit()...TX = [16384] bytes -- Rx = [16384] bytes Tx buffer [0xA1B84860] to [0xA1B88860]. Rx buffer [0xA1B88880] to [0xA1B8C880]. VBridge:: NK add MAC: [0-60-65-2-DA-FB] Connecting to Desktop KITL: Connected host IP: 1 Port: 1086 .. this is the output of the serial debug A: Neo, have you by any chance tried looking into your firewall to see if it might be blocking traffic on any particular ports? Wireshark/netmon might be able to help you here if that's the issue. davbo-msft (Moderator)[2010-3-30 12:48]: Q: I lost spell check, how can i get it back A: Hello - can you give additional details about your question? Is this related to a Windows CE Embedded application? masatos_MSFT (Expert)[2010-3-30 12:51]: Q: When attempting to run the CETK cellcore tests the documentation states the pre-requisites include "stinger.ini", "ltk.ini" but windows CE doesn't provide these or document what they fully need to contain. Implicitly you also need "datatrans.xml" which isn't supplied. If you get around this error and steal these from Windows Mobile instead, when you try and run the CETK tests you get a data abort in radiometricsdll.dll. How should we invoke the cellcore parts of CETK? A: Hi Pev, what version of Windows CE and CETK are you using? I do not have the expertise to answer this question, but can find somebody who can. Travis Hobrla [MS] (Expert)[2010-3-30 12:52]: Q: I don't see a kitlcore.dll in my OS. is my debug image fails to load because of that? A: kitl.dll should be all that's needed, kitlcore.lib is linked into that. Travis Hobrla [MS] (Expert)[2010-3-30 12:55]: Q: I've got a platform (not developed by myself) where I2C bus support has to be provided through the OAL as the kernel needs to talk to devices such as the power management IC and gas gauge so a 'proper' I2C driver hanging off device manager isn't possible. This happens to be a polled driver, so obviously it hits the system hard when either under lots of traffic or an error condition occurs and the driver constantly polls. I originally thought that there was no straightforward way to make such code interrupt driven in the kernel (as it's a cludge) but I realised that that's exactly what ETHDBG drivers do. Is there any reason why I shouldn't have a go at implementing a similar mechanism for our kernel resident I2C driver? If not, are there any obvious pitfalls - I've not seen any other BSP's do this in the past... A: You can make a 'proper' driver that calls down into the OAL to do the actual I2C transactions. Alternatively you can build an interrupt-based version in the OAL where you handle everything in the ISR. There is nothing wrong with that so long as the rest of your drivers and app threads can handle longer times with interrupts off while you are servicing I2C interrupts. Sing Wee [MS] (Expert)[2010-3-30 12:55]: Q: I am having trouble with my mouse, I have the microsoft wireless mobile mouse 3000, when I push the scroll button I am suppose to have autoscroll instead it shows other web pages,Can you help me out tell me what to do!!! A: Sorry, this current chat is about Windows Embedded Compact. Hope you're able to find an answer to your question elsewhere. davbo-msft (Moderator)[2010-3-30 12:56]: Q: Is the Silverlight Animation "Spline" a BezierSpline? A: Spline - http://msdn.microsoft.com/en-us/library/ee501495.aspx<BR< a>>   masatos_MSFT (Expert)[2010-3-30 12:57]: Thanks for the info Pev. I will follow up with the CETK experts here and get back to you. davbo-msft (Moderator)[2010-3-30 12:59]: Q: Spline- bad link A: http://msdn.microsoft.com/en-us/library/ee501495.aspx davbo-msft (Moderator)[2010-3-30 13:0]: Q: Sorry, got to tirm the ">" A: No Worries http://msdn.microsoft.com/en-us/library/ee501495.aspx davbo-msft (Moderator)[2010-3-30 13:0]: Hello everyone, we are just about out of time. Thank you for joining us for our Windows Embedded CE 6.0 chat today! <http://www.Microsoft.com/Embedded>; A special thank you to the product group members for coming out. The transcript of today’s chat will be posted online as soon as possible, to <http://msdn.microsoft.com/en-us/chats>;. We’ll see you again for another chat next month. Please check <http://msdn.microsoft.com/en-us/chats>; for the list of upcoming chats. If you still have unanswered questions, let me suggest that you post them on one of our newsgroups on <http://msdn.microsoft.com/en-us/windowsembedded/ce/default.aspx> -Windows Embedded CE 6.0 R3 Now Available! <http://msdn.microsoft.com/windowsembedded/ce/dd630616.aspx>; davbo-msft (Moderator)[2010-3-30 13:1]: Q: hi everybody. I would like to know if there is something know about a bug in RTC API (VOIP), especially when using SIP. According the to the analysis with application verifyier there is a heap link in rtcdllmedia.dll. All of the unreleased chunks seem to have a size of 6560 bytes. A: I will follow up with the Networking Team for a response. davbo-msft (Moderator)[2010-3-30 13:1]: Q: Hi, we've problems with debugging of applications (= breakpoints in Platform Builder will be ignored) over KITL on Windows CE 5.0, if the PDB files are large (over 60MB). Are there any limitations to size of the PDB files? A: I will follow up with the tools team for a response and post with the transcript. Sing Wee [MS] (Expert)[2010-3-30 13:1]: Q: I am unable to use the target control in my development environment. any ideas? A: Make sure you have SYSGEN_SHELL=1 set in your build environment. davbo-msft (Moderator)[2010-3-30 13:3]: Q: what are the main differences between Object Store and RAM disk ? They are both in RAM...are there performance differences ? access differences ? A: I will follow up with the Core Team and get a response posted with the transcript to MSDN  The Questions   [2010-3-30 12:57]: Thanks for the info Pev. I will follow up with the CETK experts here and get back to you. [2010-3-30 12:59]:   [2010-3-30 13:0]:   [2010-3-30 13:0]: Hello everyone, we are just about out of time. Thank you for joining us for our Windows Embedded CE 6.0 chat today! <http://www.Microsoft.com/Embedded>; A special thank you to the product group members for coming out. The transcript of today’s chat will be posted online as soon as possible, to <http://msdn.microsoft.com/en-us/chats>;. We’ll see you again for another chat next month. Please check <http://msdn.microsoft.com/en-us/chats>; for the list of upcoming chats. If you still have unanswered questions, let me suggest that you post them on one of our newsgroups on <http://msdn.microsoft.com/en-us/windowsembedded/ce/default.aspx> -Windows Embedded CE 6.0 R3 Now Available! <http://msdn.microsoft.com/windowsembedded/ce/dd630616.aspx>; [2010-3-30 13:1]: [2010-3-30 13:1]: [2010-3-30 13:1]: [2010-3-30 13:3]: neo (Guest)[2010-3-30 11:37]: Hi all KellyG (Guest)[2010-3-30 11:37]: Hi KellyG (Guest)[2010-3-30 11:37]: I have a question unrelated to windows Ce embedded, can you please help me?? neo (Guest)[2010-3-30 11:38]: I need to implement hardware timers on my windows CE 6.0 device to trigger events at microsecond intervals! c neo (Guest)[2010-3-30 11:38]: yes. post it. May be i cud give a try KellyG (Guest)[2010-3-30 11:38]: My Product key listed on my tower is not the product key I need for microsoft office, but that is the only product key listed. neo (Guest)[2010-3-30 11:39]: I hope this is a chat for windows embedded. please post ur queries in office forums KellyG (Guest)[2010-3-30 11:39]: it is but i could not find a forum for office neo (Guest)[2010-3-30 11:40]: I think moderators will help u out. @ davbo-msft: can u help this guy? neo (Guest)[2010-3-30 11:41]: Q: I need to implement hardware timers on my windows CE 6.0 device to trigger events at microsecond intervals. Where should i start? davbo-msft (Moderator)[2010-3-30 11:50]: Our chat today covers the topic of Windows Embedded CE! 1. This chat will last for one hour. During this hour, our Experts will respond to as many questions as they can. Please understand that there may be some questions we cannot respond to due to lack of information or because the information is not yet public. 2. We encourage you to submit questions for our Experts. To do so, type your questions in the send box, select the “ask the Experts” box and click SEND. Questions sent directly to the Guest Chat room will not be answered by the Experts, but we encourage other community members to assist. 3. We ask that you stay on topic for the duration of the chat. This helps the Guests and Experts follow the conversation more easily. We invite you to ask off topic questions after this chat is over, but not during. 4. Please abide by the Chat Code of Conduct. Chat code of conduct: <http://msdn.microsoft.com/chats/chatroom.aspx?ctl=hlp#Conduct>; Pev (Guest)[2010-3-30 11:54]: Evening! davbo-msft (Moderator)[2010-3-30 11:54]: Hello everyone this is Dave Boyce - I worked in the Multimedia area for Windows CE. neo (Guest)[2010-3-30 11:55]: hello dave neo (Guest)[2010-3-30 11:55]: The chat code of conduct link is not working! Pev (Guest)[2010-3-30 11:56]: Best be polite just in case then ;-) neo (Guest)[2010-3-30 11:56]: davbo-msft (Moderator)[2010-3-30 11:57]: I'll check out the issue w/ the link paolopat (Guest)[2010-3-30 12:0]: Hello davbo-msft (Moderator)[2010-3-30 12:0]: We are pleased to welcome our Experts for today’s chat. I will have them introduce themselves now. Chat will begin in a couple of minutes. <http://www.Microsoft.com/Embedded>; paolopat (Guest)[2010-3-30 12:3]: Hello Experts ! neo (Guest)[2010-3-30 12:3]: Welcome all! paolopat (Guest)[2010-3-30 12:3]: Q: I want to partition my NAND Flash device. One partition to use for hive ragistry and the other for the apps and data. The only way to do it is programmatically or setting some registry values ? neo (Guest)[2010-3-30 12:3]: Q: I need to implement hardware timers on my windows CE 6.0 device to trigger events at microsecond intervals. Where should i start? neo (Guest)[2010-3-30 12:5]: Q: My CPU is Intel celeron M processor 1Ghz. Pev (Guest)[2010-3-30 12:5]: neo: if your silicon has multiple general purpose timers, pick one that's not in use for the system timer / profiler and set it up to trigger irqs for your purpose. You can't guarantee hard realtime type responses though... GarySwalling (Guest)[2010-3-30 12:5]: Q: Is Windows Phone 7 related to Windows CE? If so, can you tell me what version of Windows CE is the basis? Is it in fact the new version of Windows Mobile? Pev (Guest)[2010-3-30 12:6]: Q: Hi guys, what's the formal way to report bugs back to the core team / product team? The mechanism of calling the support phone number every time is really onerous and time-consuming. Is there another mechanism? paolopat (Guest)[2010-3-30 12:6]: Q: But the operation for creating the partitions ? neo (Guest)[2010-3-30 12:6]: Q: If i need to implement it using interrupt handlers, What are all the files that I should look at? GPM (Guest)[2010-3-30 12:6]: Q: I would like to get a handle to a Silverlight screen section, is that possiable? Jhony (Guest)[2010-3-30 12:7]: Q: I created a OS design with KITL and kernel debugger enabled. But I am unable to connect to the target for debugging. I am getting the following error when i try to connect with the device. PB Debugger Cannot initialize the Kernel Debugger. PB Debugger Debugger could not initialize connection. PB Debugger The Kernel Debugger is waiting to connect with target. PB Debugger The Kernel Debugger has been disconnected successfully. Charles (Guest)[2010-3-30 12:7]: What will be different in Windows Compact 7 from CE 6.0? neo (Guest)[2010-3-30 12:8]: Can I have the book's name please? kiefs_dev (Guest)[2010-3-30 12:8]: Q: hi everybody. I would like to know if there is something know about a bug in RTC API (VOIP), especially when using SIP. According the to the analysis with application verifyier there is a heap link in rtcdllmedia.dll. All of the unreleased chunks seem to have a size of 6560 bytes. paolopat (Guest)[2010-3-30 12:10]: Q: So...I have to modify file system code to create 2 partition at system startup ?!! I haven't understood.... neo (Guest)[2010-3-30 12:10]: Q: Do u mean ISR/IST implementation? How can i register an interrupt? What kind of interrupt should i register? neo (Guest)[2010-3-30 12:11]: Q: Can I have the book's name please? Charles (Guest)[2010-3-30 12:11]: Q: What will be different in Windows Compact 7 from CE 6.0? PaulT (Guest)[2010-3-30 12:11]: neo: I'd say that you really need the docs for YOUR BSP, not generic documents for BSPs in general. Each BSP may be architected differently. If you're using the CEPC BSP, then the documentation that comes with Platform Builder is a reasonable place to look. GPM (Guest)[2010-3-30 12:11]: Q: If one has an image on a Silverlight page, it seems to be cached. How would one refresh that cache after changing the underlying image? Elektrobit (Guest)[2010-3-30 12:12]: Q: Hi, we've problems with debugging of applications (= breakpoints in Platform Builder will be ignored) over KITL on Windows CE 5.0, if the PDB files are large (over 60MB). Are there any limitations to size of the PDB files? Jhony (Guest)[2010-3-30 12:15]: Q: I am using CE 6.0. There is no cesvchost process running in my system. alexquisi (Guest)[2010-3-30 12:15]: Q: Hi, I saw that the ATADISK is quite generic and des not have any optimizations. Do you have any advice to consider while tryin to improve the performance of it? Jhony (Guest)[2010-3-30 12:17]: Windows XP service pack 1 Jhony (Guest)[2010-3-30 12:17]: Q: sorry! Windows XP SP3 neo (Guest)[2010-3-30 12:19]: Q: The link for developing device drivers is not working. can u please check that? paolopat (Guest)[2010-3-30 12:20]: Q: I have a NAND Flash on my target device. On this flash I have the hive registry and an application.I have observed that when the NAND flash is fully, the system startup time is longer....is there a degradation of NAND use that influences the startup time ? Why ? Pev (Guest)[2010-3-30 12:20]: Q: When attempting to run the CETK cellcore tests the documentation states the pre-requisites include "stinger.ini", "ltk.ini" but windows CE doesn't provide these or document what they fully need to contain. Implicitly you also need "datatrans.xml" which isn't supplied. If you get around this error and steal these from Windows Mobile instead, when you try and run the CETK tests you get a data abort in radiometricsdll.dll. How should we invoke the cellcore parts of CETK? Pev (Guest)[2010-3-30 12:21]: Hi all, Pev (Guest)[2010-3-30 12:21]: oops Pev (Guest)[2010-3-30 12:21]: :-D Pev (Guest)[2010-3-30 12:24]: Typically for SoC devices you name your hardware specific libraries in the form "SOCDIRNAME_LIBNAME". In our platform "OMAP35XX_TPS659XX_TI_V1" if you do this we cause the catalog parser to die... For example if we have a library "Musbfn_OMAP35XX_TPS659XX_TI_V1.dll" entering this in the catalogs pbcxml file in a <module> section causes the XML parser to fail with : Pev (Guest)[2010-3-30 12:25]: Q: Error 3 The 'urn:Microsoft.PlatformBuilder/Catalog:Module' element is        invalid - The value '012345678901234567890123456789.dll' is invalid         according to its datatype         'urn:Microsoft.PlatformBuilder/Catalog:CatalogFileName' - The actual         length is greater than the MaxLength value. GPM (Guest)[2010-3-30 12:25]: Q: Writable bitmap, is there an example of the syntax? Pev (Guest)[2010-3-30 12:25]: Q: Typically for SoC devices you name your hardware specific libraries in the form "SOCDIRNAME_LIBNAME". In our platform "OMAP35XX_TPS659XX_TI_V1" if you do this we cause the catalog parser to die... For example if we have a library "Musbfn_OMAP35XX_TPS659XX_TI_V1.dll" entering this in the catalogs pbcxml file in a <module> section causes the XML parser to fail with : Error 3 The 'urn:Microsoft.PlatformBuilder/Catalog:Module' element is        invalid - The value '012345678901234567890123456789.dll' is invalid         according to its datatype         'urn:Microsoft.PlatformBuilder/Catalog:CatalogFileName' - The actual         length is greater than the MaxLength value. Pev (Guest)[2010-3-30 12:25]: sorry, messed up submission there! GPM (Guest)[2010-3-30 12:26]: Q: I would like to get a handle to a Silverlight screen section, is that possiable? GPM (Guest)[2010-3-30 12:28]: Q: IXRVisualHost::GetHWND() exactly what I needed Thanks, PaulT (Guest)[2010-3-30 12:29]: GPM: You don't have to keep submitting the questions. The chat experts have an application that they're using to follow the chat and all Ask the Experts questions are logged. Jhony (Guest)[2010-3-30 12:29]: Q: I am getting this error only when I select the KdStub as the debugger in Target device connectivity. neo (Guest)[2010-3-30 12:30]: Q: ok. thanks for the book's link Pev (Guest)[2010-3-30 12:31]: Hm, did those two I submitted get picked up by anyone? neo (Guest)[2010-3-30 12:33]: Q: If I select Active KTIL, My OS doesn't boots. It says "loading NK.EXE at 0x<xxxxx> location" after that nothing comes in the debug log. PaulT (Guest)[2010-3-30 12:34]: Pev: PaulT (Guest)[2010-3-30 12:35]: Pev: I'm sure they did. The guys who are actually on the chat may not be experts in that part of things. That's usually the explanation when you don't get an answer in 10 minutes or so. Pev (Guest)[2010-3-30 12:36]: Ah, fair enough Susie (Guest)[2010-3-30 12:36]: My Outlook Express incoming mail is corrput. No ONE has been able to fix the problem, Dell or Norton. I have dial up I'm in a rural area Jhony (Guest)[2010-3-30 12:37]: Q: I have tried that and I am getting the same error. Pev (Guest)[2010-3-30 12:37]: Susie : Use Thunderbird instead :-D PaulT (Guest)[2010-3-30 12:37]: Susie: Sorry, but this chat is not about Windows, but Embedded (like what runs on a phone). Your best chance is to find a local expert or talk to your ISP. paolopat (Guest)[2010-3-30 12:37]: Q: what are the main differences between Object Store and RAM disk ? They are both in RAM...are there performance differences ? access differences ? Susie (Guest)[2010-3-30 12:38]: My computer knowlege is very limited, what is Thunderbird? Pev (Guest)[2010-3-30 12:38]: A different email client :-D neo (Guest)[2010-3-30 12:39]: Q: KITL: *** Device Name CEPC56059 *** WARN: KITL will run in polling mode VBridge:: built on [Jul 10 2009] time [10:20:14] VBridgeInit()...TX = [16384] bytes -- Rx = [16384] bytes Tx buffer [0xA1B84860] to [0xA1B88860]. Rx buffer [0xA1B88880] to [0xA1B8C880]. VBridge:: NK add MAC: [0-60-65-2-DA-FB] Connecting to Desktop KITL: Connected host IP: 1 Port: 1086 .. this is the output of the serial debug Susie (Guest)[2010-3-30 12:39]: Do I need to uninstall Outlook Express youngboyzie (Guest)[2010-3-30 12:39]: I need to start battery calibration for my new battery for my dell inspiron 1525 laptop and should be able to reach the BIOS screen by hitting f2 but this isnt working... help? Pev (Guest)[2010-3-30 12:39]: Nah, you can run it instead - you'll still need help from your ISP to configure it I expect Jhony (Guest)[2010-3-30 12:39]: Q: Both is happening via Ethernet. PaulT (Guest)[2010-3-30 12:40]: youngboyzie: You're off-topic. This is not a general chat for Windows and certainly not for Dell. You'll have to ask Dell how to get to setup; it's their machine. bill (Guest)[2010-3-30 12:41]: I lost spell check, how can i get et back neo (Guest)[2010-3-30 12:42]: Q: I didn't do that. I have to try. Jhony (Guest)[2010-3-30 12:43]: Q: Ok. I will do it then. bill (Guest)[2010-3-30 12:43]: Q: I lost spell check, how can i get it back PaulT (Guest)[2010-3-30 12:44]: bill: This isn't a general Windows chat. There are some Web forums that you might try. GarySwalling (Guest)[2010-3-30 12:45]: Q: Thanks, I found the Phone 7 presentation at http://live.visitmix.com/MIX10/Sessions/CL13 GPM (Guest)[2010-3-30 12:45]: Q: Is the Silverlight Animation "Spline" a BezierSpline? neo (Guest)[2010-3-30 12:46]: Q: ok. I'll do it. thanks Pev (Guest)[2010-3-30 12:46]: Whowever was asking about KITL connection : I've had this loads in the past. I think I started debugging last time by using wireshark to see what was happening on the network then setting up the OAL_ETHER and OAL_FUNC and OAL_VERBOSE as well as OAL_KITL flags to see what was actually happening in the driver.... Pev (Guest)[2010-3-30 12:47]: I'd generally make sure that you're testing though a 10baseT hub (instead of anything faster) and forcing Active KITL in polled mode too... neo (Guest)[2010-3-30 12:48]: Q: I disabled the firewall in my PC. Pev (Guest)[2010-3-30 12:50]: Q: I've got a platform (not developed by myself) where I2C bus support has to be provided through the OAL as the kernel needs to talk to devices such as the power management IC and gas gauge so a 'proper' I2C driver hanging off device manager isn't possible. This happens to be a polled driver, so obviously it hits the system hard when either under lots of traffic or an error condition occurs and the driver constantly polls. I originally thought that there was no straightforward way to make such code interrupt driven in the kernel (as it's a cludge) but I realised that that's exactly what ETHDBG drivers do. Is there any reason why I shouldn't have a go at implementing a similar mechanism for our kernel resident I2C driver? If not, are there any obvious pitfalls - I've not seen any other BSP's do this in the past... neo (Guest)[2010-3-30 12:51]: Q: I don't see a kitlcore.dll in my OS. is my debug image fails to load because of that? Pev (Guest)[2010-3-30 12:52]: Q: Hi masatos, I'm using Windows Embedded CE 6.0 with R3 and patched to feb 2010's QFE's (with it's associated CETK version) this is a machine with only CE 6.0 on (no conflicts with earlier CE or WM...) neo (Guest)[2010-3-30 12:54]: ok. Got it neo (Guest)[2010-3-30 12:54]: Q: ok. Got it Roundman (Guest)[2010-3-30 12:55]: Q: I am having trouble with my mouse, I have the microsoft wireless mobile mouse 3000, when I push the scroll button I am suppose to have autoscroll instead it shows other web pages,Can you help me out tell me what to do!!! Pev (Guest)[2010-3-30 12:55]: Hey neo, debugging kitl issues is really frustrating but dont lose heart :-) neo (Guest)[2010-3-30 12:55]: @ pev : u fixed the problem of KITL after that? neo (Guest)[2010-3-30 12:56]: I am getting the same error again and again. I even cleaned my environment and tried in a fresh PC. But didn't succeed yet Pev (Guest)[2010-3-30 12:56]: Well, eventually - my experiences probably won't help you as different platforms have different reasons for doing that neo (Guest)[2010-3-30 12:56]: I think so PaulT (Guest)[2010-3-30 12:58]: neo: Have you searched the old messages in microsoft.public.windowsce.platbuilder? It seems to me that there was a packet size situation where it was possible to have problems with KITL connections based on a setting on the PC. Google Groups, groups.google.com, Advanced Groups Search will allow you to search a single newsgroup or a set of newsgroups easily. GPM (Guest)[2010-3-30 12:58]: Q: Spline- bad link PaulT (Guest)[2010-3-30 12:58]: GPM: without the > at the end does it work? It seems to for me... neo (Guest)[2010-3-30 12:58]: But some times if i try to connect to the device again. The Image information is seen in the serial debug. what does that mean?Download BIN file information: ----------------------------------------------------- [0]: Base Address=0x220000 Length=0x18DAADC Received a broadcast message !CheckUDP: Not UDP (proto = 0x00000001) after this i am getting the old errors. PB debugger cannot initialize ... GPM (Guest)[2010-3-30 12:59]: Q: Sorry, got to tirm the ">" neo (Guest)[2010-3-30 12:59]: ok paul. I ll look into that. davbo-msft (Moderator)[2010-3-30 13:0]: Hello everyone, we are just about out of time. Thank you for joining us for our Windows Embedded CE 6.0 chat today! <http://www.Microsoft.com/Embedded>; A special thank you to the product group members for coming out. The transcript of today’s chat will be posted online as soon as possible, to <http://msdn.microsoft.com/en-us/chats>;. We’ll see you again for another chat next month. Please check <http://msdn.microsoft.com/en-us/chats>; for the list of upcoming chats. If you still have unanswered questions, let me suggest that you post them on one of our newsgroups on <http://msdn.microsoft.com/en-us/windowsembedded/ce/default.aspx> -Windows Embedded CE 6.0 R3 Now Available! <http://msdn.microsoft.com/windowsembedded/ce/dd630616.aspx>; neo (Guest)[2010-3-30 13:1]: Q: I am unable to use the target control in my development environment. any ideas? Pev (Guest)[2010-3-30 13:1]: Sure, if KITL isn't connected target control won't work as it runs over kitl... neo (Guest)[2010-3-30 13:1]: ok .thanks pev neo (Guest)[2010-3-30 13:2]: yes. sysgen_shell is set to 1 neo (Guest)[2010-3-30 13:2]: Q: yes. sysgen_shell is set to 1 Marcelovk (Guest)[2010-3-30 13:2]: Q: Is there any way to extract the default command lines of the tests in CETK? I want to have it running unconnected from the desktop.   Copyright © 2010 – Bruce Eitman All Rights Reserved

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• Table sorting & pagination with jQuery and Razor in ASP.NET MVC

  - by hajan

  Introduction jQuery enjoys living inside pages which are built on top of ASP.NET MVC Framework. The ASP.NET MVC is a place where things are organized very well and it is quite hard to make them dirty, especially because the pattern enforces you on purity (you can still make it dirty if you want so ;) ). We all know how easy is to build a HTML table with a header row, footer row and table rows showing some data. With ASP.NET MVC we can do this pretty easy, but, the result will be pure HTML table which only shows data, but does not includes sorting, pagination or some other advanced features that we were used to have in the ASP.NET WebForms GridView. Ok, there is the WebGrid MVC Helper, but what if we want to make something from pure table in our own clean style? In one of my recent projects, I’ve been using the jQuery tablesorter and tablesorter.pager plugins that go along. You don’t need to know jQuery to make this work… You need to know little CSS to create nice design for your table, but of course you can use mine from the demo… So, what you will see in this blog is how to attach this plugin to your pure html table and a div for pagination and make your table with advanced sorting and pagination features.   Demo Project Resources The resources I’m using for this demo project are shown in the following solution explorer window print screen: Content/images – folder that contains all the up/down arrow images, pagination buttons etc. You can freely replace them with your own, but keep the names the same if you don’t want to change anything in the CSS we will built later. Content/Site.css – The main css theme, where we will add the theme for our table too Controllers/HomeController.cs – The controller I’m using for this project Models/Person.cs – For this demo, I’m using Person.cs class Scripts – jquery-1.4.4.min.js, jquery.tablesorter.js, jquery.tablesorter.pager.js – required script to make the magic happens Views/Home/Index.cshtml – Index view (razor view engine) the other items are not important for the demo. ASP.NET MVC 1. Model In this demo I use only one Person class which defines Person entity with several properties. You can use your own model, maybe one which will access data from database or any other resource. Person.cs public class Person {     public string Name { get; set; }     public string Surname { get; set; }     public string Email { get; set; }     public int? Phone { get; set; }     public DateTime? DateAdded { get; set; }     public int? Age { get; set; }     public Person(string name, string surname, string email,         int? phone, DateTime? dateadded, int? age)     {         Name = name;         Surname = surname;         Email = email;         Phone = phone;         DateAdded = dateadded;         Age = age;     } } 2. View In our example, we have only one Index.chtml page where Razor View engine is used. Razor view engine is my favorite for ASP.NET MVC because it’s very intuitive, fluid and keeps your code clean. 3. Controller Since this is simple example with one page, we use one HomeController.cs where we have two methods, one of ActionResult type (Index) and another GetPeople() used to create and return list of people. HomeController.cs public class HomeController : Controller {     //     // GET: /Home/     public ActionResult Index()     {         ViewBag.People = GetPeople();         return View();     }     public List<Person> GetPeople()     {         List<Person> listPeople = new List<Person>();                  listPeople.Add(new Person("Hajan", "Selmani", "[email protected]", 070070070,DateTime.Now, 25));                     listPeople.Add(new Person("Straight", "Dean", "[email protected]", 123456789, DateTime.Now.AddDays(-5), 35));         listPeople.Add(new Person("Karsen", "Livia", "[email protected]", 46874651, DateTime.Now.AddDays(-2), 31));         listPeople.Add(new Person("Ringer", "Anne", "[email protected]", null, DateTime.Now, null));         listPeople.Add(new Person("O'Leary", "Michael", "[email protected]", 32424344, DateTime.Now, 44));         listPeople.Add(new Person("Gringlesby", "Anne", "[email protected]", null, DateTime.Now.AddDays(-9), 18));         listPeople.Add(new Person("Locksley", "Stearns", "[email protected]", 2135345, DateTime.Now, null));         listPeople.Add(new Person("DeFrance", "Michel", "[email protected]", 235325352, DateTime.Now.AddDays(-18), null));         listPeople.Add(new Person("White", "Johnson", null, null, DateTime.Now.AddDays(-22), 55));         listPeople.Add(new Person("Panteley", "Sylvia", null, 23233223, DateTime.Now.AddDays(-1), 32));         listPeople.Add(new Person("Blotchet-Halls", "Reginald", null, 323243423, DateTime.Now, 26));         listPeople.Add(new Person("Merr", "South", "[email protected]", 3232442, DateTime.Now.AddDays(-5), 85));         listPeople.Add(new Person("MacFeather", "Stearns", "[email protected]", null, DateTime.Now, null));         return listPeople;     } }   TABLE CSS/HTML DESIGN Now, lets start with the implementation. First of all, lets create the table structure and the main CSS. 1. HTML Structure @{     Layout = null;     } <!DOCTYPE html> <html> <head>     <title>ASP.NET & jQuery</title>     <!-- referencing styles, scripts and writing custom js scripts will go here --> </head> <body>     <div>         <table class="tablesorter">             <thead>                 <tr>                     <th> value </th>                 </tr>             </thead>             <tbody>                 <tr>                     <td>value</td>                 </tr>             </tbody>             <tfoot>                 <tr>                     <th> value </th>                 </tr>             </tfoot>         </table>         <div id="pager">                      </div>     </div> </body> </html> So, this is the main structure you need to create for each of your tables where you want to apply the functionality we will create. Of course the scripts are referenced once ;). As you see, our table has class tablesorter and also we have a div with id pager. In the next steps we will use both these to create the needed functionalities. The complete Index.cshtml coded to get the data from controller and display in the page is: <body>     <div>         <table class="tablesorter">             <thead>                 <tr>                     <th>Name</th>                     <th>Surname</th>                     <th>Email</th>                     <th>Phone</th>                     <th>Date Added</th>                 </tr>             </thead>             <tbody>                 @{                     foreach (var p in ViewBag.People)                     {                                 <tr>                         <td>@p.Name</td>                         <td>@p.Surname</td>                         <td>@p.Email</td>                         <td>@p.Phone</td>                         <td>@p.DateAdded</td>                     </tr>                     }                 }             </tbody>             <tfoot>                 <tr>                     <th>Name</th>                     <th>Surname</th>                     <th>Email</th>                     <th>Phone</th>                     <th>Date Added</th>                 </tr>             </tfoot>         </table>         <div id="pager" style="position: none;">             <form>             <img src="@Url.Content("~/Content/images/first.png")" class="first" />             <img src="@Url.Content("~/Content/images/prev.png")" class="prev" />             <input type="text" class="pagedisplay" />             <img src="@Url.Content("~/Content/images/next.png")" class="next" />             <img src="@Url.Content("~/Content/images/last.png")" class="last" />             <select class="pagesize">                 <option selected="selected" value="5">5</option>                 <option value="10">10</option>                 <option value="20">20</option>                 <option value="30">30</option>                 <option value="40">40</option>             </select>             </form>         </div>     </div> </body> So, mainly the structure is the same. I have added @Razor code to create table with data retrieved from the ViewBag.People which has been filled with data in the home controller. 2. CSS Design The CSS code I’ve created is: /* DEMO TABLE */ body {     font-size: 75%;     font-family: Verdana, Tahoma, Arial, "Helvetica Neue", Helvetica, Sans-Serif;     color: #232323;     background-color: #fff; } table { border-spacing:0; border:1px solid gray;} table.tablesorter thead tr .header {     background-image: url(images/bg.png);     background-repeat: no-repeat;     background-position: center right;     cursor: pointer; } table.tablesorter tbody td {     color: #3D3D3D;     padding: 4px;     background-color: #FFF;     vertical-align: top; } table.tablesorter tbody tr.odd td {     background-color:#F0F0F6; } table.tablesorter thead tr .headerSortUp {     background-image: url(images/asc.png); } table.tablesorter thead tr .headerSortDown {     background-image: url(images/desc.png); } table th { width:150px;            border:1px outset gray;            background-color:#3C78B5;            color:White;            cursor:pointer; } table thead th:hover { background-color:Yellow; color:Black;} table td { width:150px; border:1px solid gray;} PAGINATION AND SORTING Now, when everything is ready and we have the data, lets make pagination and sorting functionalities 1. jQuery Scripts referencing <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" /> <script src="@Url.Content("~/Scripts/jquery-1.4.4.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.tablesorter.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.tablesorter.pager.js")" type="text/javascript"></script> 2. jQuery Sorting and Pagination script   <script type="text/javascript">     $(function () {         $("table.tablesorter").tablesorter({ widthFixed: true, sortList: [[0, 0]] })         .tablesorterPager({ container: $("#pager"), size: $(".pagesize option:selected").val() });     }); </script> So, with only two lines of code, I’m using both tablesorter and tablesorterPager plugins, giving some options to both these. Options added: tablesorter - widthFixed: true – gives fixed width of the columns tablesorter - sortList[[0,0]] – An array of instructions for per-column sorting and direction in the format: [[columnIndex, sortDirection], ... ] where columnIndex is a zero-based index for your columns left-to-right and sortDirection is 0 for Ascending and 1 for Descending. A valid argument that sorts ascending first by column 1 and then column 2 looks like: [[0,0],[1,0]] (source: http://tablesorter.com/docs/) tablesorterPager – container: $(“#pager”) – tells the pager container, the div with id pager in our case. tablesorterPager – size: the default size of each page, where I get the default value selected, so if you put selected to any other of the options in your select list, you will have this number of rows as default per page for the table too. END RESULTS 1. Table once the page is loaded (default results per page is 5 and is automatically sorted by 1st column as sortList is specified) 2. Sorted by Phone Descending 3. Changed pagination to 10 items per page 4. Sorted by Phone and Name (use SHIFT to sort on multiple columns) 5. Sorted by Date Added 6. Page 3, 5 items per page   ADDITIONAL ENHANCEMENTS We can do additional enhancements to the table. We can make search for each column. I will cover this in one of my next blogs. Stay tuned. DEMO PROJECT You can download demo project source code from HERE.CONCLUSION Once you finish with the demo, run your page and open the source code. You will be amazed of the purity of your code.Working with pagination in client side can be very useful. One of the benefits is performance, but if you have thousands of rows in your tables, you will get opposite result when talking about performance. Hence, sometimes it is nice idea to make pagination on back-end. So, the compromise between both approaches would be best to combine both of them. I use at most up to 500 rows on client-side and once the user reach the last page, we can trigger ajax postback which can get the next 500 rows using server-side pagination of the same data. I would like to recommend the following blog post http://weblogs.asp.net/gunnarpeipman/archive/2010/09/14/returning-paged-results-from-repositories-using-pagedresult-lt-t-gt.aspx, which will help you understand how to return page results from repository. I hope this was helpful post for you. Wait for my next posts ;). Please do let me know your feedback. Best Regards, Hajan

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• Automating Solaris 11 Zones Installation Using The Automated Install Server

  - by Orgad Kimchi

  Introduction How to use the Oracle Solaris 11 Automated install server in order to automate the Solaris 11 Zones installation. In this document I will demonstrate how to setup the Automated Install server in order to provide hands off installation process for the Global Zone and two Non Global Zones located on the same system. Architecture layout: Figure 1. Architecture layout Prerequisite Setup the Automated install server (AI) using the following instructions “How to Set Up Automated Installation Services for Oracle Solaris 11” The first step in this setup will be creating two Solaris 11 Zones configuration files. Step 1: Create the Solaris 11 Zones configuration files  The Solaris Zones configuration files should be in the format of the zonecfg export command. # zonecfg -z zone1 export > /var/tmp/zone1# cat /var/tmp/zone1 create -b set brand=solaris set zonepath=/rpool/zones/zone1 set autoboot=true set ip-type=exclusive add anet set linkname=net0 set lower-link=auto set configure-allowed-address=true set link-protection=mac-nospoof set mac-address=random end  Create a backup copy of this file under a different name, for example, zone2. # cp /var/tmp/zone1 /var/tmp/zone2 Modify the second configuration file with the zone2 configuration information You should change the zonepath for example: set zonepath=/rpool/zones/zone2 Step2: Copy and share the Zones configuration files  Create the NFS directory for the Zones configuration files # mkdir /export/zone_config Share the directory for the Zones configuration file # share –o ro /export/zone_config Copy the Zones configuration files into the NFS shared directory # cp /var/tmp/zone1 /var/tmp/zone2  /export/zone_config Verify that the NFS share has been created using the following command # share export_zone_config      /export/zone_config     nfs     sec=sys,ro Step 3: Add the Global Zone as client to the Install Service Use the installadm create-client command to associate client (Global Zone) with the install service To find the MAC address of a system, use the dladm command as described in the dladm(1M) man page. The following command adds the client (Global Zone) with MAC address 0:14:4f:2:a:19 to the s11x86service install service. # installadm create-client -e “0:14:4f:2:a:19" -n s11x86service You can verify the client creation using the following command # installadm list –c Service Name  Client Address     Arch   Image Path ------------  --------------     ----   ---------- s11x86service 00:14:4F:02:0A:19  i386   /export/auto_install/s11x86service We can see the client install service name (s11x86service), MAC address (00:14:4F:02:0A:19 and Architecture (i386). Step 4: Global Zone manifest setup  First, get a list of the installation services and the manifests associated with them: # installadm list -m Service Name   Manifest        Status ------------   --------        ------ default-i386   orig_default   Default s11x86service  orig_default   Default Then probe the s11x86service and the default manifest associated with it. The -m switch reflects the name of the manifest associated with a service. Since we want to capture that output into a file, we redirect the output of the command as follows: # installadm export -n s11x86service -m orig_default >  /var/tmp/orig_default.xml Create a backup copy of this file under a different name, for example, orig-default2.xml, and edit the copy. # cp /var/tmp/orig_default.xml /var/tmp/orig_default2.xml Use the configuration element in the AI manifest for the client system to specify non-global zones. Use the name attribute of the configuration element to specify the name of the zone. Use the source attribute to specify the location of the config file for the zone.The source location can be any http:// or file:// location that the client can access during installation. The following sample AI manifest specifies two Non-Global Zones: zone1 and zone2 You should replace the server_ip with the ip address of the NFS server. <!DOCTYPE auto_install SYSTEM "file:///usr/share/install/ai.dtd.1"> <auto_install>   <ai_instance>     <target>       <logical>         <zpool name="rpool" is_root="true">           <filesystem name="export" mountpoint="/export"/>           <filesystem name="export/home"/>           <be name="solaris"/>         </zpool>       </logical>     </target>     <software type="IPS">       <source>         <publisher name="solaris">           <origin name="http://pkg.oracle.com/solaris/release"/>         </publisher>       </source>       <software_data action="install">         <name>pkg:/entire@latest</name>         <name>pkg:/group/system/solaris-large-server</name>       </software_data>     </software>     <configuration type="zone" name="zone1" source="file:///net/server_ip/export/zone_config/zone1"/>     <configuration type="zone" name="zone2" source="file:///net/server_ip/export/zone_config/zone2"/>   </ai_instance> </auto_install> The following example adds the /var/tmp/orig_default2.xml AI manifest to the s11x86service install service # installadm create-manifest -n s11x86service -f /var/tmp/orig_default2.xml -m gzmanifest You can verify the manifest creation using the following command # installadm list -n s11x86service  -m Service/Manifest Name  Status   Criteria ---------------------  ------   -------- s11x86service    orig_default        Default  None    gzmanifest          Inactive None We can see from the command output that the new manifest named gzmanifest has been created and associated with the s11x86service install service. Step 5: Non Global Zone manifest setup The AI manifest for non-global zone installation is similar to the AI manifest for installing the global zone. If you do not provide a custom AI manifest for a non-global zone, the default AI manifest for Zones is used The default AI manifest for Zones is available at /usr/share/auto_install/manifest/zone_default.xml. In this example we should use the default AI manifest for zones The following sample default AI manifest for zones # cat /usr/share/auto_install/manifest/zone_default.xml <?xml version="1.0" encoding="UTF-8"?> <!--  Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved. --> <!DOCTYPE auto_install SYSTEM "file:///usr/share/install/ai.dtd.1"> <auto_install>     <ai_instance name="zone_default">         <target>             <logical>                 <zpool name="rpool">                     <!--                       Subsequent <filesystem> entries instruct an installer                       to create following ZFS datasets:                           <root_pool>/export         (mounted on /export)                           <root_pool>/export/home    (mounted on /export/home)                       Those datasets are part of standard environment                       and should be always created.                       In rare cases, if there is a need to deploy a zone                       without these datasets, either comment out or remove                       <filesystem> entries. In such scenario, it has to be also                       assured that in case of non-interactive post-install                       configuration, creation of initial user account is                       disabled in related system configuration profile.                       Otherwise the installed zone would fail to boot.                     -->                     <filesystem name="export" mountpoint="/export"/>                     <filesystem name="export/home"/>                     <be name="solaris">                         <options>                             <option name="compression" value="on"/>                         </options>                     </be>                 </zpool>             </logical>         </target>         <software type="IPS">             <destination>                 <image>                     <!-- Specify locales to install -->                     <facet set="false">facet.locale.*</facet>                     <facet set="true">facet.locale.de</facet>                     <facet set="true">facet.locale.de_DE</facet>                     <facet set="true">facet.locale.en</facet>                     <facet set="true">facet.locale.en_US</facet>                     <facet set="true">facet.locale.es</facet>                     <facet set="true">facet.locale.es_ES</facet>                     <facet set="true">facet.locale.fr</facet>                     <facet set="true">facet.locale.fr_FR</facet>                     <facet set="true">facet.locale.it</facet>                     <facet set="true">facet.locale.it_IT</facet>                     <facet set="true">facet.locale.ja</facet>                     <facet set="true">facet.locale.ja_*</facet>                     <facet set="true">facet.locale.ko</facet>                     <facet set="true">facet.locale.ko_*</facet>                     <facet set="true">facet.locale.pt</facet>                     <facet set="true">facet.locale.pt_BR</facet>                     <facet set="true">facet.locale.zh</facet>                     <facet set="true">facet.locale.zh_CN</facet>                     <facet set="true">facet.locale.zh_TW</facet>                 </image>             </destination>             <software_data action="install">                 <name>pkg:/group/system/solaris-small-server</name>             </software_data>         </software>     </ai_instance> </auto_install> (optional) We can customize the default AI manifest for Zones Create a backup copy of this file under a different name, for example, zone_default2.xml and edit the copy # cp /usr/share/auto_install/manifest/zone_default.xml /var/tmp/zone_default2.xml Edit the copy (/var/tmp/zone_default2.xml) The following example adds the /var/tmp/zone_default2.xml AI manifest to the s11x86service install service and specifies that zone1 and zone2 should use this manifest. # installadm create-manifest -n s11x86service -f /var/tmp/zone_default2.xml -m zones_manifest -c zonename="zone1 zone2" Note: Do not use the following elements or attributes in a non-global zone AI manifest:     The auto_reboot attribute of the ai_instance element     The http_proxy attribute of the ai_instance element     The disk child element of the target element     The noswap attribute of the logical element     The nodump attribute of the logical element     The configuration element Step 6: Global Zone profile setup We are going to create a global zone configuration profile which includes the host information for example: host name, ip address name services etc… # sysconfig create-profile –o /var/tmp/gz_profile.xml You need to provide the host information for example:     Default router     Root password     DNS information The output should eventually disappear and be replaced by the initial screen of the System Configuration Tool (see Figure 2), where you can do the final configuration. Figure 2. Profile creation menu You can validate the profile using the following command # installadm validate -n s11x86service –P /var/tmp/gz_profile.xml Validating static profile gz_profile.xml...  Passed Next, instantiate a profile with the install service. In our case, use the following syntax for doing this # installadm create-profile -n s11x86service  -f /var/tmp/gz_profile.xml -p  gz_profile You can verify profile creation using the following command # installadm list –n s11x86service  -p Service/Profile Name  Criteria --------------------  -------- s11x86service    gz_profile         None We can see that the gz_profie has been created and associated with the s11x86service Install service. Step 7: Setup the Solaris Zones configuration profiles The step should be similar to the Global zone profile creation on step 6 # sysconfig create-profile –o /var/tmp/zone1_profile.xml # sysconfig create-profile –o /var/tmp/zone2_profile.xml You can validate the profiles using the following command # installadm validate -n s11x86service -P /var/tmp/zone1_profile.xml Validating static profile zone1_profile.xml...  Passed # installadm validate -n s11x86service -P /var/tmp/zone2_profile.xml Validating static profile zone2_profile.xml...  Passed Next, associate the profiles with the install service The following example adds the zone1_profile.xml configuration profile to the s11x86service  install service and specifies that zone1 should use this profile. # installadm create-profile -n s11x86service  -f  /var/tmp/zone1_profile.xml -p zone1_profile -c zonename=zone1 The following example adds the zone2_profile.xml configuration profile to the s11x86service  install service and specifies that zone2 should use this profile. # installadm create-profile -n s11x86service  -f  /var/tmp/zone2_profile.xml -p zone2_profile -c zonename=zone2 You can verify the profiles creation using the following command # installadm list -n s11x86service -p Service/Profile Name  Criteria --------------------  -------- s11x86service    zone1_profile      zonename = zone1    zone2_profile      zonename = zone2    gz_profile         None We can see that we have three profiles in the s11x86service  install service     Global Zone  gz_profile     zone1            zone1_profile     zone2            zone2_profile. Step 8: Global Zone setup Associate the global zone client with the manifest and the profile that we create in the previous steps The following example adds the manifest and profile to the client (global zone), where: gzmanifest  is the name of the manifest. gz_profile  is the name of the configuration profile. mac="0:14:4f:2:a:19" is the client (global zone) mac address s11x86service is the install service name. # installadm set-criteria -m  gzmanifest  –p  gz_profile  -c mac="0:14:4f:2:a:19" -n s11x86service You can verify the manifest and profile association using the following command # installadm list -n s11x86service -p  -m Service/Manifest Name  Status   Criteria ---------------------  ------   -------- s11x86service    gzmanifest                   mac  = 00:14:4F:02:0A:19    orig_default        Default  None Service/Profile Name  Criteria --------------------  -------- s11x86service    gz_profile         mac      = 00:14:4F:02:0A:19    zone2_profile      zonename = zone2    zone1_profile      zonename = zone1 Step 9: Provision the host with the Non-Global Zones The next step is to boot the client system off the network and provision it using the Automated Install service that we just set up. First, boot the client system. Figure 3 shows the network boot attempt (when done on an x86 system): Figure 3. Network Boot Then you will be prompted by a GRUB menu, with a timer, as shown in Figure 4. The default selection (the "Text Installer and command line" option) is highlighted.  Press the down arrow to highlight the second option labeled Automated Install, and then press Enter. The reason we need to do this is because we want to prevent a system from being automatically re-installed if it were to be booted from the network accidentally. Figure 4. GRUB Menu What follows is the continuation of a networked boot from the Automated Install server,. The client downloads a mini-root (a small set of files in which to successfully run the installer), identifies the location of the Automated Install manifest on the network, retrieves that manifest, and then processes it to identify the address of the IPS repository from which to obtain the desired software payload. Non-Global Zones are installed and configured on the first reboot after the Global Zone is installed. You can list all the Solaris Zones status using the following command # zoneadm list -civ Once the Zones are in running state you can login into the Zone using the following command # zlogin –z zone1 Troubleshooting Automated Installations If an installation to a client system failed, you can find the client log at /system/volatile/install_log. NOTE: Zones are not installed if any of the following errors occurs:     A zone config file is not syntactically correct.     A collision exists among zone names, zone paths, or delegated ZFS datasets in the set of zones to be installed     Required datasets are not configured in the global zone. For more troubleshooting information see “Installing Oracle Solaris 11 Systems” Conclusion This paper demonstrated the benefits of using the Automated Install server to simplify the Non Global Zones setup, including the creation and configuration of the global zone manifest and the Solaris Zones profiles.

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• value types in the vm

  - by john.rose

  value types in the vm p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} p.p2 {margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times} p.p3 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times} p.p4 {margin: 0.0px 0.0px 15.0px 0.0px; font: 14.0px Times} p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier} p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier; min-height: 17.0px} p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p8 {margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px; font: 14.0px Times; min-height: 18.0px} p.p9 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p10 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; color: #000000} li.li1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} li.li7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} span.s1 {font: 14.0px Courier} span.s2 {color: #000000} span.s3 {font: 14.0px Courier; color: #000000} ol.ol1 {list-style-type: decimal} Or, enduring values for a changing world. Introduction A value type is a data type which, generally speaking, is designed for being passed by value in and out of methods, and stored by value in data structures. The only value types which the Java language directly supports are the eight primitive types. Java indirectly and approximately supports value types, if they are implemented in terms of classes. For example, both Integer and String may be viewed as value types, especially if their usage is restricted to avoid operations appropriate to Object. In this note, we propose a definition of value types in terms of a design pattern for Java classes, accompanied by a set of usage restrictions. We also sketch the relation of such value types to tuple types (which are a JVM-level notion), and point out JVM optimizations that can apply to value types. This note is a thought experiment to extend the JVM’s performance model in support of value types. The demonstration has two phases.  Initially the extension can simply use design patterns, within the current bytecode architecture, and in today’s Java language. But if the performance model is to be realized in practice, it will probably require new JVM bytecode features, changes to the Java language, or both.  We will look at a few possibilities for these new features. An Axiom of Value In the context of the JVM, a value type is a data type equipped with construction, assignment, and equality operations, and a set of typed components, such that, whenever two variables of the value type produce equal corresponding values for their components, the values of the two variables cannot be distinguished by any JVM operation. Here are some corollaries: A value type is immutable, since otherwise a copy could be constructed and the original could be modified in one of its components, allowing the copies to be distinguished. Changing the component of a value type requires construction of a new value. The equals and hashCode operations are strictly component-wise. If a value type is represented by a JVM reference, that reference cannot be successfully synchronized on, and cannot be usefully compared for reference equality. A value type can be viewed in terms of what it doesn’t do. We can say that a value type omits all value-unsafe operations, which could violate the constraints on value types.  These operations, which are ordinarily allowed for Java object types, are pointer equality comparison (the acmp instruction), synchronization (the monitor instructions), all the wait and notify methods of class Object, and non-trivial finalize methods. The clone method is also value-unsafe, although for value types it could be treated as the identity function. Finally, and most importantly, any side effect on an object (however visible) also counts as an value-unsafe operation. A value type may have methods, but such methods must not change the components of the value. It is reasonable and useful to define methods like toString, equals, and hashCode on value types, and also methods which are specifically valuable to users of the value type. Representations of Value Value types have two natural representations in the JVM, unboxed and boxed. An unboxed value consists of the components, as simple variables. For example, the complex number x=(1+2i), in rectangular coordinate form, may be represented in unboxed form by the following pair of variables: /*Complex x = Complex.valueOf(1.0, 2.0):*/ double x_re = 1.0, x_im = 2.0; These variables might be locals, parameters, or fields. Their association as components of a single value is not defined to the JVM. Here is a sample computation which computes the norm of the difference between two complex numbers: double distance(/*Complex x:*/ double x_re, double x_im,         /*Complex y:*/ double y_re, double y_im) {     /*Complex z = x.minus(y):*/     double z_re = x_re - y_re, z_im = x_im - y_im;     /*return z.abs():*/     return Math.sqrt(z_re*z_re + z_im*z_im); } A boxed representation groups component values under a single object reference. The reference is to a ‘wrapper class’ that carries the component values in its fields. (A primitive type can naturally be equated with a trivial value type with just one component of that type. In that view, the wrapper class Integer can serve as a boxed representation of value type int.) The unboxed representation of complex numbers is practical for many uses, but it fails to cover several major use cases: return values, array elements, and generic APIs. The two components of a complex number cannot be directly returned from a Java function, since Java does not support multiple return values. The same story applies to array elements: Java has no ’array of structs’ feature. (Double-length arrays are a possible workaround for complex numbers, but not for value types with heterogeneous components.) By generic APIs I mean both those which use generic types, like Arrays.asList and those which have special case support for primitive types, like String.valueOf and PrintStream.println. Those APIs do not support unboxed values, and offer some problems to boxed values. Any ’real’ JVM type should have a story for returns, arrays, and API interoperability. The basic problem here is that value types fall between primitive types and object types. Value types are clearly more complex than primitive types, and object types are slightly too complicated. Objects are a little bit dangerous to use as value carriers, since object references can be compared for pointer equality, and can be synchronized on. Also, as many Java programmers have observed, there is often a performance cost to using wrapper objects, even on modern JVMs. Even so, wrapper classes are a good starting point for talking about value types. If there were a set of structural rules and restrictions which would prevent value-unsafe operations on value types, wrapper classes would provide a good notation for defining value types. This note attempts to define such rules and restrictions. Let’s Start Coding Now it is time to look at some real code. Here is a definition, written in Java, of a complex number value type. @ValueSafe public final class Complex implements java.io.Serializable {     // immutable component structure:     public final double re, im;     private Complex(double re, double im) {         this.re = re; this.im = im;     }     // interoperability methods:     public String toString() { return "Complex("+re+","+im+")"; }     public List<Double> asList() { return Arrays.asList(re, im); }     public boolean equals(Complex c) {         return re == c.re && im == c.im;     }     public boolean equals(@ValueSafe Object x) {         return x instanceof Complex && equals((Complex) x);     }     public int hashCode() {         return 31*Double.valueOf(re).hashCode()                 + Double.valueOf(im).hashCode();     }     // factory methods:     public static Complex valueOf(double re, double im) {         return new Complex(re, im);     }     public Complex changeRe(double re2) { return valueOf(re2, im); }     public Complex changeIm(double im2) { return valueOf(re, im2); }     public static Complex cast(@ValueSafe Object x) {         return x == null ? ZERO : (Complex) x;     }     // utility methods and constants:     public Complex plus(Complex c)  { return new Complex(re+c.re, im+c.im); }     public Complex minus(Complex c) { return new Complex(re-c.re, im-c.im); }     public double abs() { return Math.sqrt(re*re + im*im); }     public static final Complex PI = valueOf(Math.PI, 0.0);     public static final Complex ZERO = valueOf(0.0, 0.0); } This is not a minimal definition, because it includes some utility methods and other optional parts.  The essential elements are as follows: The class is marked as a value type with an annotation. The class is final, because it does not make sense to create subclasses of value types. The fields of the class are all non-private and final.  (I.e., the type is immutable and structurally transparent.) From the supertype Object, all public non-final methods are overridden. The constructor is private. Beyond these bare essentials, we can observe the following features in this example, which are likely to be typical of all value types: One or more factory methods are responsible for value creation, including a component-wise valueOf method. There are utility methods for complex arithmetic and instance creation, such as plus and changeIm. There are static utility constants, such as PI. The type is serializable, using the default mechanisms. There are methods for converting to and from dynamically typed references, such as asList and cast. The Rules In order to use value types properly, the programmer must avoid value-unsafe operations.  A helpful Java compiler should issue errors (or at least warnings) for code which provably applies value-unsafe operations, and should issue warnings for code which might be correct but does not provably avoid value-unsafe operations.  No such compilers exist today, but to simplify our account here, we will pretend that they do exist. A value-safe type is any class, interface, or type parameter marked with the @ValueSafe annotation, or any subtype of a value-safe type.  If a value-safe class is marked final, it is in fact a value type.  All other value-safe classes must be abstract.  The non-static fields of a value class must be non-public and final, and all its constructors must be private. Under the above rules, a standard interface could be helpful to define value types like Complex.  Here is an example: @ValueSafe public interface ValueType extends java.io.Serializable {     // All methods listed here must get redefined.     // Definitions must be value-safe, which means     // they may depend on component values only.     List<? extends Object> asList();     int hashCode();     boolean equals(@ValueSafe Object c);     String toString(); } //@ValueSafe inherited from supertype: public final class Complex implements ValueType { … The main advantage of such a conventional interface is that (unlike an annotation) it is reified in the runtime type system.  It could appear as an element type or parameter bound, for facilities which are designed to work on value types only.  More broadly, it might assist the JVM to perform dynamic enforcement of the rules for value types. Besides types, the annotation @ValueSafe can mark fields, parameters, local variables, and methods.  (This is redundant when the type is also value-safe, but may be useful when the type is Object or another supertype of a value type.)  Working forward from these annotations, an expression E is defined as value-safe if it satisfies one or more of the following: The type of E is a value-safe type. E names a field, parameter, or local variable whose declaration is marked @ValueSafe. E is a call to a method whose declaration is marked @ValueSafe. E is an assignment to a value-safe variable, field reference, or array reference. E is a cast to a value-safe type from a value-safe expression. E is a conditional expression E0 ? E1 : E2, and both E1 and E2 are value-safe. Assignments to value-safe expressions and initializations of value-safe names must take their values from value-safe expressions. A value-safe expression may not be the subject of a value-unsafe operation.  In particular, it cannot be synchronized on, nor can it be compared with the “==” operator, not even with a null or with another value-safe type. In a program where all of these rules are followed, no value-type value will be subject to a value-unsafe operation.  Thus, the prime axiom of value types will be satisfied, that no two value type will be distinguishable as long as their component values are equal. More Code To illustrate these rules, here are some usage examples for Complex: Complex pi = Complex.valueOf(Math.PI, 0); Complex zero = pi.changeRe(0);  //zero = pi; zero.re = 0; ValueType vtype = pi; @SuppressWarnings("value-unsafe")   Object obj = pi; @ValueSafe Object obj2 = pi; obj2 = new Object();  // ok List<Complex> clist = new ArrayList<Complex>(); clist.add(pi);  // (ok assuming List.add param is @ValueSafe) List<ValueType> vlist = new ArrayList<ValueType>(); vlist.add(pi);  // (ok) List<Object> olist = new ArrayList<Object>(); olist.add(pi);  // warning: "value-unsafe" boolean z = pi.equals(zero); boolean z1 = (pi == zero);  // error: reference comparison on value type boolean z2 = (pi == null);  // error: reference comparison on value type boolean z3 = (pi == obj2);  // error: reference comparison on value type synchronized (pi) { }  // error: synch of value, unpredictable result synchronized (obj2) { }  // unpredictable result Complex qq = pi; qq = null;  // possible NPE; warning: “null-unsafe" qq = (Complex) obj;  // warning: “null-unsafe" qq = Complex.cast(obj);  // OK @SuppressWarnings("null-unsafe")   Complex empty = null;  // possible NPE qq = empty;  // possible NPE (null pollution) The Payoffs It follows from this that either the JVM or the java compiler can replace boxed value-type values with unboxed ones, without affecting normal computations.  Fields and variables of value types can be split into their unboxed components.  Non-static methods on value types can be transformed into static methods which take the components as value parameters. Some common questions arise around this point in any discussion of value types. Why burden the programmer with all these extra rules?  Why not detect programs automagically and perform unboxing transparently?  The answer is that it is easy to break the rules accidently unless they are agreed to by the programmer and enforced.  Automatic unboxing optimizations are tantalizing but (so far) unreachable ideal.  In the current state of the art, it is possible exhibit benchmarks in which automatic unboxing provides the desired effects, but it is not possible to provide a JVM with a performance model that assures the programmer when unboxing will occur.  This is why I’m writing this note, to enlist help from, and provide assurances to, the programmer.  Basically, I’m shooting for a good set of user-supplied “pragmas” to frame the desired optimization. Again, the important thing is that the unboxing must be done reliably, or else programmers will have no reason to work with the extra complexity of the value-safety rules.  There must be a reasonably stable performance model, wherein using a value type has approximately the same performance characteristics as writing the unboxed components as separate Java variables. There are some rough corners to the present scheme.  Since Java fields and array elements are initialized to null, value-type computations which incorporate uninitialized variables can produce null pointer exceptions.  One workaround for this is to require such variables to be null-tested, and the result replaced with a suitable all-zero value of the value type.  That is what the “cast” method does above. Generically typed APIs like List<T> will continue to manipulate boxed values always, at least until we figure out how to do reification of generic type instances.  Use of such APIs will elicit warnings until their type parameters (and/or relevant members) are annotated or typed as value-safe.  Retrofitting List<T> is likely to expose flaws in the present scheme, which we will need to engineer around.  Here are a couple of first approaches: public interface java.util.List<@ValueSafe T> extends Collection<T> { … public interface java.util.List<T extends Object|ValueType> extends Collection<T> { … (The second approach would require disjunctive types, in which value-safety is “contagious” from the constituent types.) With more transformations, the return value types of methods can also be unboxed.  This may require significant bytecode-level transformations, and would work best in the presence of a bytecode representation for multiple value groups, which I have proposed elsewhere under the title “Tuples in the VM”. But for starters, the JVM can apply this transformation under the covers, to internally compiled methods.  This would give a way to express multiple return values and structured return values, which is a significant pain-point for Java programmers, especially those who work with low-level structure types favored by modern vector and graphics processors.  The lack of multiple return values has a strong distorting effect on many Java APIs. Even if the JVM fails to unbox a value, there is still potential benefit to the value type.  Clustered computing systems something have copy operations (serialization or something similar) which apply implicitly to command operands.  When copying JVM objects, it is extremely helpful to know when an object’s identity is important or not.  If an object reference is a copied operand, the system may have to create a proxy handle which points back to the original object, so that side effects are visible.  Proxies must be managed carefully, and this can be expensive.  On the other hand, value types are exactly those types which a JVM can “copy and forget” with no downside. Array types are crucial to bulk data interfaces.  (As data sizes and rates increase, bulk data becomes more important than scalar data, so arrays are definitely accompanying us into the future of computing.)  Value types are very helpful for adding structure to bulk data, so a successful value type mechanism will make it easier for us to express richer forms of bulk data. Unboxing arrays (i.e., arrays containing unboxed values) will provide better cache and memory density, and more direct data movement within clustered or heterogeneous computing systems.  They require the deepest transformations, relative to today’s JVM.  There is an impedance mismatch between value-type arrays and Java’s covariant array typing, so compromises will need to be struck with existing Java semantics.  It is probably worth the effort, since arrays of unboxed value types are inherently more memory-efficient than standard Java arrays, which rely on dependent pointer chains. It may be sufficient to extend the “value-safe” concept to array declarations, and allow low-level transformations to change value-safe array declarations from the standard boxed form into an unboxed tuple-based form.  Such value-safe arrays would not be convertible to Object[] arrays.  Certain connection points, such as Arrays.copyOf and System.arraycopy might need additional input/output combinations, to allow smooth conversion between arrays with boxed and unboxed elements. Alternatively, the correct solution may have to wait until we have enough reification of generic types, and enough operator overloading, to enable an overhaul of Java arrays. Implicit Method Definitions The example of class Complex above may be unattractively complex.  I believe most or all of the elements of the example class are required by the logic of value types. If this is true, a programmer who writes a value type will have to write lots of error-prone boilerplate code.  On the other hand, I think nearly all of the code (except for the domain-specific parts like plus and minus) can be implicitly generated. Java has a rule for implicitly defining a class’s constructor, if no it defines no constructors explicitly.  Likewise, there are rules for providing default access modifiers for interface members.  Because of the highly regular structure of value types, it might be reasonable to perform similar implicit transformations on value types.  Here’s an example of a “highly implicit” definition of a complex number type: public class Complex implements ValueType {  // implicitly final     public double re, im;  // implicitly public final     //implicit methods are defined elementwise from te fields:     //  toString, asList, equals(2), hashCode, valueOf, cast     //optionally, explicit methods (plus, abs, etc.) would go here } In other words, with the right defaults, a simple value type definition can be a one-liner.  The observant reader will have noticed the similarities (and suitable differences) between the explicit methods above and the corresponding methods for List<T>. Another way to abbreviate such a class would be to make an annotation the primary trigger of the functionality, and to add the interface(s) implicitly: public @ValueType class Complex { … // implicitly final, implements ValueType (But to me it seems better to communicate the “magic” via an interface, even if it is rooted in an annotation.) Implicitly Defined Value Types So far we have been working with nominal value types, which is to say that the sequence of typed components is associated with a name and additional methods that convey the intention of the programmer.  A simple ordered pair of floating point numbers can be variously interpreted as (to name a few possibilities) a rectangular or polar complex number or Cartesian point.  The name and the methods convey the intended meaning. But what if we need a truly simple ordered pair of floating point numbers, without any further conceptual baggage?  Perhaps we are writing a method (like “divideAndRemainder”) which naturally returns a pair of numbers instead of a single number.  Wrapping the pair of numbers in a nominal type (like “QuotientAndRemainder”) makes as little sense as wrapping a single return value in a nominal type (like “Quotient”).  What we need here are structural value types commonly known as tuples. For the present discussion, let us assign a conventional, JVM-friendly name to tuples, roughly as follows: public class java.lang.tuple.$DD extends java.lang.tuple.Tuple {      double $1, $2; } Here the component names are fixed and all the required methods are defined implicitly.  The supertype is an abstract class which has suitable shared declarations.  The name itself mentions a JVM-style method parameter descriptor, which may be “cracked” to determine the number and types of the component fields. The odd thing about such a tuple type (and structural types in general) is it must be instantiated lazily, in response to linkage requests from one or more classes that need it.  The JVM and/or its class loaders must be prepared to spin a tuple type on demand, given a simple name reference, $xyz, where the xyz is cracked into a series of component types.  (Specifics of naming and name mangling need some tasteful engineering.) Tuples also seem to demand, even more than nominal types, some support from the language.  (This is probably because notations for non-nominal types work best as combinations of punctuation and type names, rather than named constructors like Function3 or Tuple2.)  At a minimum, languages with tuples usually (I think) have some sort of simple bracket notation for creating tuples, and a corresponding pattern-matching syntax (or “destructuring bind”) for taking tuples apart, at least when they are parameter lists.  Designing such a syntax is no simple thing, because it ought to play well with nominal value types, and also with pre-existing Java features, such as method parameter lists, implicit conversions, generic types, and reflection.  That is a task for another day. Other Use Cases Besides complex numbers and simple tuples there are many use cases for value types.  Many tuple-like types have natural value-type representations. These include rational numbers, point locations and pixel colors, and various kinds of dates and addresses. Other types have a variable-length ‘tail’ of internal values. The most common example of this is String, which is (mathematically) a sequence of UTF-16 character values. Similarly, bit vectors, multiple-precision numbers, and polynomials are composed of sequences of values. Such types include, in their representation, a reference to a variable-sized data structure (often an array) which (somehow) represents the sequence of values. The value type may also include ’header’ information. Variable-sized values often have a length distribution which favors short lengths. In that case, the design of the value type can make the first few values in the sequence be direct ’header’ fields of the value type. In the common case where the header is enough to represent the whole value, the tail can be a shared null value, or even just a null reference. Note that the tail need not be an immutable object, as long as the header type encapsulates it well enough. This is the case with String, where the tail is a mutable (but never mutated) character array. Field types and their order must be a globally visible part of the API.  The structure of the value type must be transparent enough to have a globally consistent unboxed representation, so that all callers and callees agree about the type and order of components  that appear as parameters, return types, and array elements.  This is a trade-off between efficiency and encapsulation, which is forced on us when we remove an indirection enjoyed by boxed representations.  A JVM-only transformation would not care about such visibility, but a bytecode transformation would need to take care that (say) the components of complex numbers would not get swapped after a redefinition of Complex and a partial recompile.  Perhaps constant pool references to value types need to declare the field order as assumed by each API user. This brings up the delicate status of private fields in a value type.  It must always be possible to load, store, and copy value types as coordinated groups, and the JVM performs those movements by moving individual scalar values between locals and stack.  If a component field is not public, what is to prevent hostile code from plucking it out of the tuple using a rogue aload or astore instruction?  Nothing but the verifier, so we may need to give it more smarts, so that it treats value types as inseparable groups of stack slots or locals (something like long or double). My initial thought was to make the fields always public, which would make the security problem moot.  But public is not always the right answer; consider the case of String, where the underlying mutable character array must be encapsulated to prevent security holes.  I believe we can win back both sides of the tradeoff, by training the verifier never to split up the components in an unboxed value.  Just as the verifier encapsulates the two halves of a 64-bit primitive, it can encapsulate the the header and body of an unboxed String, so that no code other than that of class String itself can take apart the values. Similar to String, we could build an efficient multi-precision decimal type along these lines: public final class DecimalValue extends ValueType {     protected final long header;     protected private final BigInteger digits;     public DecimalValue valueOf(int value, int scale) {         assert(scale >= 0);         return new DecimalValue(((long)value << 32) + scale, null);     }     public DecimalValue valueOf(long value, int scale) {         if (value == (int) value)             return valueOf((int)value, scale);         return new DecimalValue(-scale, new BigInteger(value));     } } Values of this type would be passed between methods as two machine words. Small values (those with a significand which fits into 32 bits) would be represented without any heap data at all, unless the DecimalValue itself were boxed. (Note the tension between encapsulation and unboxing in this case.  It would be better if the header and digits fields were private, but depending on where the unboxing information must “leak”, it is probably safer to make a public revelation of the internal structure.) Note that, although an array of Complex can be faked with a double-length array of double, there is no easy way to fake an array of unboxed DecimalValues.  (Either an array of boxed values or a transposed pair of homogeneous arrays would be reasonable fallbacks, in a current JVM.)  Getting the full benefit of unboxing and arrays will require some new JVM magic. Although the JVM emphasizes portability, system dependent code will benefit from using machine-level types larger than 64 bits.  For example, the back end of a linear algebra package might benefit from value types like Float4 which map to stock vector types.  This is probably only worthwhile if the unboxing arrays can be packed with such values. More Daydreams A more finely-divided design for dynamic enforcement of value safety could feature separate marker interfaces for each invariant.  An empty marker interface Unsynchronizable could cause suitable exceptions for monitor instructions on objects in marked classes.  More radically, a Interchangeable marker interface could cause JVM primitives that are sensitive to object identity to raise exceptions; the strangest result would be that the acmp instruction would have to be specified as raising an exception. @ValueSafe public interface ValueType extends java.io.Serializable,         Unsynchronizable, Interchangeable { … public class Complex implements ValueType {     // inherits Serializable, Unsynchronizable, Interchangeable, @ValueSafe     … It seems possible that Integer and the other wrapper types could be retro-fitted as value-safe types.  This is a major change, since wrapper objects would be unsynchronizable and their references interchangeable.  It is likely that code which violates value-safety for wrapper types exists but is uncommon.  It is less plausible to retro-fit String, since the prominent operation String.intern is often used with value-unsafe code. We should also reconsider the distinction between boxed and unboxed values in code.  The design presented above obscures that distinction.  As another thought experiment, we could imagine making a first class distinction in the type system between boxed and unboxed representations.  Since only primitive types are named with a lower-case initial letter, we could define that the capitalized version of a value type name always refers to the boxed representation, while the initial lower-case variant always refers to boxed.  For example: complex pi = complex.valueOf(Math.PI, 0); Complex boxPi = pi;  // convert to boxed myList.add(boxPi); complex z = myList.get(0);  // unbox Such a convention could perhaps absorb the current difference between int and Integer, double and Double. It might also allow the programmer to express a helpful distinction among array types. As said above, array types are crucial to bulk data interfaces, but are limited in the JVM.  Extending arrays beyond the present limitations is worth thinking about; for example, the Maxine JVM implementation has a hybrid object/array type.  Something like this which can also accommodate value type components seems worthwhile.  On the other hand, does it make sense for value types to contain short arrays?  And why should random-access arrays be the end of our design process, when bulk data is often sequentially accessed, and it might make sense to have heterogeneous streams of data as the natural “jumbo” data structure.  These considerations must wait for another day and another note. More Work It seems to me that a good sequence for introducing such value types would be as follows: Add the value-safety restrictions to an experimental version of javac. Code some sample applications with value types, including Complex and DecimalValue. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. A staggered roll-out like this would decouple language changes from bytecode changes, which is always a convenient thing. A similar investigation should be applied (concurrently) to array types.  In this case, it seems to me that the starting point is in the JVM: Add an experimental unboxing array data structure to a production JVM, perhaps along the lines of Maxine hybrids.  No bytecode or language support is required at first; everything can be done with encapsulated unsafe operations and/or method handles. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. That’s enough musing me for now.  Back to work!

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• How John Got 15x Improvement Without Really Trying

  - by rchrd

  The following article was published on a Sun Microsystems website a number of years ago by John Feo. It is still useful and worth preserving. So I'm republishing it here.  How I Got 15x Improvement Without Really Trying John Feo, Sun Microsystems Taking ten "personal" program codes used in scientific and engineering research, the author was able to get from 2 to 15 times performance improvement easily by applying some simple general optimization techniques. Introduction Scientific research based on computer simulation depends on the simulation for advancement. The research can advance only as fast as the computational codes can execute. The codes' efficiency determines both the rate and quality of results. In the same amount of time, a faster program can generate more results and can carry out a more detailed simulation of physical phenomena than a slower program. Highly optimized programs help science advance quickly and insure that monies supporting scientific research are used as effectively as possible. Scientific computer codes divide into three broad categories: ISV, community, and personal. ISV codes are large, mature production codes developed and sold commercially. The codes improve slowly over time both in methods and capabilities, and they are well tuned for most vendor platforms. Since the codes are mature and complex, there are few opportunities to improve their performance solely through code optimization. Improvements of 10% to 15% are typical. Examples of ISV codes are DYNA3D, Gaussian, and Nastran. Community codes are non-commercial production codes used by a particular research field. Generally, they are developed and distributed by a single academic or research institution with assistance from the community. Most users just run the codes, but some develop new methods and extensions that feed back into the general release. The codes are available on most vendor platforms. Since these codes are younger than ISV codes, there are more opportunities to optimize the source code. Improvements of 50% are not unusual. Examples of community codes are AMBER, CHARM, BLAST, and FASTA. Personal codes are those written by single users or small research groups for their own use. These codes are not distributed, but may be passed from professor-to-student or student-to-student over several years. They form the primordial ocean of applications from which community and ISV codes emerge. Government research grants pay for the development of most personal codes. This paper reports on the nature and performance of this class of codes. Over the last year, I have looked at over two dozen personal codes from more than a dozen research institutions. The codes cover a variety of scientific fields, including astronomy, atmospheric sciences, bioinformatics, biology, chemistry, geology, and physics. The sources range from a few hundred lines to more than ten thousand lines, and are written in Fortran, Fortran 90, C, and C++. For the most part, the codes are modular, documented, and written in a clear, straightforward manner. They do not use complex language features, advanced data structures, programming tricks, or libraries. I had little trouble understanding what the codes did or how data structures were used. Most came with a makefile. Surprisingly, only one of the applications is parallel. All developers have access to parallel machines, so availability is not an issue. Several tried to parallelize their applications, but stopped after encountering difficulties. Lack of education and a perception that parallelism is difficult prevented most from trying. I parallelized several of the codes using OpenMP, and did not judge any of the codes as difficult to parallelize. Even more surprising than the lack of parallelism is the inefficiency of the codes. I was able to get large improvements in performance in a matter of a few days applying simple optimization techniques. Table 1 lists ten representative codes [names and affiliation are omitted to preserve anonymity]. Improvements on one processor range from 2x to 15.5x with a simple average of 4.75x. I did not use sophisticated performance tools or drill deep into the program's execution character as one would do when tuning ISV or community codes. Using only a profiler and source line timers, I identified inefficient sections of code and improved their performance by inspection. The changes were at a high level. I am sure there is another factor of 2 or 3 in each code, and more if the codes are parallelized. The study’s results show that personal scientific codes are running many times slower than they should and that the problem is pervasive. Computational scientists are not sloppy programmers; however, few are trained in the art of computer programming or code optimization. I found that most have a working knowledge of some programming language and standard software engineering practices; but they do not know, or think about, how to make their programs run faster. They simply do not know the standard techniques used to make codes run faster. In fact, they do not even perceive that such techniques exist. The case studies described in this paper show that applying simple, well known techniques can significantly increase the performance of personal codes. It is important that the scientific community and the Government agencies that support scientific research find ways to better educate academic scientific programmers. The inefficiency of their codes is so bad that it is retarding both the quality and progress of scientific research. # cacheperformance redundantoperations loopstructures performanceimprovement 1 x x 15.5 2 x 2.8 3 x x 2.5 4 x 2.1 5 x x 2.0 6 x 5.0 7 x 5.8 8 x 6.3 9 2.2 10 x x 3.3 Table 1 — Area of improvement and performance gains of 10 codes The remainder of the paper is organized as follows: sections 2, 3, and 4 discuss the three most common sources of inefficiencies in the codes studied. These are cache performance, redundant operations, and loop structures. Each section includes several examples. The last section summaries the work and suggests a possible solution to the issues raised. Optimizing cache performance Commodity microprocessor systems use caches to increase memory bandwidth and reduce memory latencies. Typical latencies from processor to L1, L2, local, and remote memory are 3, 10, 50, and 200 cycles, respectively. Moreover, bandwidth falls off dramatically as memory distances increase. Programs that do not use cache effectively run many times slower than programs that do. When optimizing for cache, the biggest performance gains are achieved by accessing data in cache order and reusing data to amortize the overhead of cache misses. Secondary considerations are prefetching, associativity, and replacement; however, the understanding and analysis required to optimize for the latter are probably beyond the capabilities of the non-expert. Much can be gained simply by accessing data in the correct order and maximizing data reuse. 6 out of the 10 codes studied here benefited from such high level optimizations. Array Accesses The most important cache optimization is the most basic: accessing Fortran array elements in column order and C array elements in row order. Four of the ten codes—1, 2, 4, and 10—got it wrong. Compilers will restructure nested loops to optimize cache performance, but may not do so if the loop structure is too complex, or the loop body includes conditionals, complex addressing, or function calls. In code 1, the compiler failed to invert a key loop because of complex addressing do I = 0, 1010, delta_x IM = I - delta_x IP = I + delta_x do J = 5, 995, delta_x JM = J - delta_x JP = J + delta_x T1 = CA1(IP, J) + CA1(I, JP) T2 = CA1(IM, J) + CA1(I, JM) S1 = T1 + T2 - 4 * CA1(I, J) CA(I, J) = CA1(I, J) + D * S1 end do end do In code 2, the culprit is conditionals do I = 1, N do J = 1, N If (IFLAG(I,J) .EQ. 0) then T1 = Value(I, J-1) T2 = Value(I-1, J) T3 = Value(I, J) T4 = Value(I+1, J) T5 = Value(I, J+1) Value(I,J) = 0.25 * (T1 + T2 + T5 + T4) Delta = ABS(T3 - Value(I,J)) If (Delta .GT. MaxDelta) MaxDelta = Delta endif enddo enddo I fixed both programs by inverting the loops by hand. Code 10 has three-dimensional arrays and triply nested loops. The structure of the most computationally intensive loops is too complex to invert automatically or by hand. The only practical solution is to transpose the arrays so that the dimension accessed by the innermost loop is in cache order. The arrays can be transposed at construction or prior to entering a computationally intensive section of code. The former requires all array references to be modified, while the latter is cost effective only if the cost of the transpose is amortized over many accesses. I used the second approach to optimize code 10. Code 5 has four-dimensional arrays and loops are nested four deep. For all of the reasons cited above the compiler is not able to restructure three key loops. Assume C arrays and let the four dimensions of the arrays be i, j, k, and l. In the original code, the index structure of the three loops is L1: for i L2: for i L3: for i for l for l for j for k for j for k for j for k for l So only L3 accesses array elements in cache order. L1 is a very complex loop—much too complex to invert. I brought the loop into cache alignment by transposing the second and fourth dimensions of the arrays. Since the code uses a macro to compute all array indexes, I effected the transpose at construction and changed the macro appropriately. The dimensions of the new arrays are now: i, l, k, and j. L3 is a simple loop and easily inverted. L2 has a loop-carried scalar dependence in k. By promoting the scalar name that carries the dependence to an array, I was able to invert the third and fourth subloops aligning the loop with cache. Code 5 is by far the most difficult of the four codes to optimize for array accesses; but the knowledge required to fix the problems is no more than that required for the other codes. I would judge this code at the limits of, but not beyond, the capabilities of appropriately trained computational scientists. Array Strides When a cache miss occurs, a line (64 bytes) rather than just one word is loaded into the cache. If data is accessed stride 1, than the cost of the miss is amortized over 8 words. Any stride other than one reduces the cost savings. Two of the ten codes studied suffered from non-unit strides. The codes represent two important classes of "strided" codes. Code 1 employs a multi-grid algorithm to reduce time to convergence. The grids are every tenth, fifth, second, and unit element. Since time to convergence is inversely proportional to the distance between elements, coarse grids converge quickly providing good starting values for finer grids. The better starting values further reduce the time to convergence. The downside is that grids of every nth element, n > 1, introduce non-unit strides into the computation. In the original code, much of the savings of the multi-grid algorithm were lost due to this problem. I eliminated the problem by compressing (copying) coarse grids into continuous memory, and rewriting the computation as a function of the compressed grid. On convergence, I copied the final values of the compressed grid back to the original grid. The savings gained from unit stride access of the compressed grid more than paid for the cost of copying. Using compressed grids, the loop from code 1 included in the previous section becomes do j = 1, GZ do i = 1, GZ T1 = CA(i+0, j-1) + CA(i-1, j+0) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) S1 = T1 + T4 - 4 * CA1(i+0, j+0) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 enddo enddo where CA and CA1 are compressed arrays of size GZ. Code 7 traverses a list of objects selecting objects for later processing. The labels of the selected objects are stored in an array. The selection step has unit stride, but the processing steps have irregular stride. A fix is to save the parameters of the selected objects in temporary arrays as they are selected, and pass the temporary arrays to the processing functions. The fix is practical if the same parameters are used in selection as in processing, or if processing comprises a series of distinct steps which use overlapping subsets of the parameters. Both conditions are true for code 7, so I achieved significant improvement by copying parameters to temporary arrays during selection. Data reuse In the previous sections, we optimized for spatial locality. It is also important to optimize for temporal locality. Once read, a datum should be used as much as possible before it is forced from cache. Loop fusion and loop unrolling are two techniques that increase temporal locality. Unfortunately, both techniques increase register pressure—as loop bodies become larger, the number of registers required to hold temporary values grows. Once register spilling occurs, any gains evaporate quickly. For multiprocessors with small register sets or small caches, the sweet spot can be very small. In the ten codes presented here, I found no opportunities for loop fusion and only two opportunities for loop unrolling (codes 1 and 3). In code 1, unrolling the outer and inner loop one iteration increases the number of result values computed by the loop body from 1 to 4, do J = 1, GZ-2, 2 do I = 1, GZ-2, 2 T1 = CA1(i+0, j-1) + CA1(i-1, j+0) T2 = CA1(i+1, j-1) + CA1(i+0, j+0) T3 = CA1(i+0, j+0) + CA1(i-1, j+1) T4 = CA1(i+1, j+0) + CA1(i+0, j+1) T5 = CA1(i+2, j+0) + CA1(i+1, j+1) T6 = CA1(i+1, j+1) + CA1(i+0, j+2) T7 = CA1(i+2, j+1) + CA1(i+1, j+2) S1 = T1 + T4 - 4 * CA1(i+0, j+0) S2 = T2 + T5 - 4 * CA1(i+1, j+0) S3 = T3 + T6 - 4 * CA1(i+0, j+1) S4 = T4 + T7 - 4 * CA1(i+1, j+1) CA(i+0, j+0) = CA1(i+0, j+0) + DD * S1 CA(i+1, j+0) = CA1(i+1, j+0) + DD * S2 CA(i+0, j+1) = CA1(i+0, j+1) + DD * S3 CA(i+1, j+1) = CA1(i+1, j+1) + DD * S4 enddo enddo The loop body executes 12 reads, whereas as the rolled loop shown in the previous section executes 20 reads to compute the same four values. In code 3, two loops are unrolled 8 times and one loop is unrolled 4 times. Here is the before for (k = 0; k < NK[u]; k++) { sum = 0.0; for (y = 0; y < NY; y++) { sum += W[y][u][k] * delta[y]; } backprop[i++]=sum; } and after code for (k = 0; k < KK - 8; k+=8) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (y = 0; y < NY; y++) { sum0 += W[y][0][k+0] * delta[y]; sum1 += W[y][0][k+1] * delta[y]; sum2 += W[y][0][k+2] * delta[y]; sum3 += W[y][0][k+3] * delta[y]; sum4 += W[y][0][k+4] * delta[y]; sum5 += W[y][0][k+5] * delta[y]; sum6 += W[y][0][k+6] * delta[y]; sum7 += W[y][0][k+7] * delta[y]; } backprop[k+0] = sum0; backprop[k+1] = sum1; backprop[k+2] = sum2; backprop[k+3] = sum3; backprop[k+4] = sum4; backprop[k+5] = sum5; backprop[k+6] = sum6; backprop[k+7] = sum7; } for one of the loops unrolled 8 times. Optimizing for temporal locality is the most difficult optimization considered in this paper. The concepts are not difficult, but the sweet spot is small. Identifying where the program can benefit from loop unrolling or loop fusion is not trivial. Moreover, it takes some effort to get it right. Still, educating scientific programmers about temporal locality and teaching them how to optimize for it will pay dividends. Reducing instruction count Execution time is a function of instruction count. Reduce the count and you usually reduce the time. The best solution is to use a more efficient algorithm; that is, an algorithm whose order of complexity is smaller, that converges quicker, or is more accurate. Optimizing source code without changing the algorithm yields smaller, but still significant, gains. This paper considers only the latter because the intent is to study how much better codes can run if written by programmers schooled in basic code optimization techniques. The ten codes studied benefited from three types of "instruction reducing" optimizations. The two most prevalent were hoisting invariant memory and data operations out of inner loops. The third was eliminating unnecessary data copying. The nature of these inefficiencies is language dependent. Memory operations The semantics of C make it difficult for the compiler to determine all the invariant memory operations in a loop. The problem is particularly acute for loops in functions since the compiler may not know the values of the function's parameters at every call site when compiling the function. Most compilers support pragmas to help resolve ambiguities; however, these pragmas are not comprehensive and there is no standard syntax. To guarantee that invariant memory operations are not executed repetitively, the user has little choice but to hoist the operations by hand. The problem is not as severe in Fortran programs because in the absence of equivalence statements, it is a violation of the language's semantics for two names to share memory. Codes 3 and 5 are C programs. In both cases, the compiler did not hoist all invariant memory operations from inner loops. Consider the following loop from code 3 for (y = 0; y < NY; y++) { i = 0; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += delta[y] * I1[i++]; } } } Since dW[y][u] can point to the same memory space as delta for one or more values of y and u, assignment to dW[y][u][k] may change the value of delta[y]. In reality, dW and delta do not overlap in memory, so I rewrote the loop as for (y = 0; y < NY; y++) { i = 0; Dy = delta[y]; for (u = 0; u < NU; u++) { for (k = 0; k < NK[u]; k++) { dW[y][u][k] += Dy * I1[i++]; } } } Failure to hoist invariant memory operations may be due to complex address calculations. If the compiler can not determine that the address calculation is invariant, then it can hoist neither the calculation nor the associated memory operations. As noted above, code 5 uses a macro to address four-dimensional arrays #define MAT4D(a,q,i,j,k) (double *)((a)->data + (q)*(a)->strides[0] + (i)*(a)->strides[3] + (j)*(a)->strides[2] + (k)*(a)->strides[1]) The macro is too complex for the compiler to understand and so, it does not identify any subexpressions as loop invariant. The simplest way to eliminate the address calculation from the innermost loop (over i) is to define a0 = MAT4D(a,q,0,j,k) before the loop and then replace all instances of *MAT4D(a,q,i,j,k) in the loop with a0[i] A similar problem appears in code 6, a Fortran program. The key loop in this program is do n1 = 1, nh nx1 = (n1 - 1) / nz + 1 nz1 = n1 - nz * (nx1 - 1) do n2 = 1, nh nx2 = (n2 - 1) / nz + 1 nz2 = n2 - nz * (nx2 - 1) ndx = nx2 - nx1 ndy = nz2 - nz1 gxx = grn(1,ndx,ndy) gyy = grn(2,ndx,ndy) gxy = grn(3,ndx,ndy) balance(n1,1) = balance(n1,1) + (force(n2,1) * gxx + force(n2,2) * gxy) * h1 balance(n1,2) = balance(n1,2) + (force(n2,1) * gxy + force(n2,2) * gyy)*h1 end do end do The programmer has written this loop well—there are no loop invariant operations with respect to n1 and n2. However, the loop resides within an iterative loop over time and the index calculations are independent with respect to time. Trading space for time, I precomputed the index values prior to the entering the time loop and stored the values in two arrays. I then replaced the index calculations with reads of the arrays. Data operations Ways to reduce data operations can appear in many forms. Implementing a more efficient algorithm produces the biggest gains. The closest I came to an algorithm change was in code 4. This code computes the inner product of K-vectors A(i) and B(j), 0 = i < N, 0 = j < M, for most values of i and j. Since the program computes most of the NM possible inner products, it is more efficient to compute all the inner products in one triply-nested loop rather than one at a time when needed. The savings accrue from reading A(i) once for all B(j) vectors and from loop unrolling. for (i = 0; i < N; i+=8) { for (j = 0; j < M; j++) { sum0 = 0.0; sum1 = 0.0; sum2 = 0.0; sum3 = 0.0; sum4 = 0.0; sum5 = 0.0; sum6 = 0.0; sum7 = 0.0; for (k = 0; k < K; k++) { sum0 += A[i+0][k] * B[j][k]; sum1 += A[i+1][k] * B[j][k]; sum2 += A[i+2][k] * B[j][k]; sum3 += A[i+3][k] * B[j][k]; sum4 += A[i+4][k] * B[j][k]; sum5 += A[i+5][k] * B[j][k]; sum6 += A[i+6][k] * B[j][k]; sum7 += A[i+7][k] * B[j][k]; } C[i+0][j] = sum0; C[i+1][j] = sum1; C[i+2][j] = sum2; C[i+3][j] = sum3; C[i+4][j] = sum4; C[i+5][j] = sum5; C[i+6][j] = sum6; C[i+7][j] = sum7; }} This change requires knowledge of a typical run; i.e., that most inner products are computed. The reasons for the change, however, derive from basic optimization concepts. It is the type of change easily made at development time by a knowledgeable programmer. In code 5, we have the data version of the index optimization in code 6. Here a very expensive computation is a function of the loop indices and so cannot be hoisted out of the loop; however, the computation is invariant with respect to an outer iterative loop over time. We can compute its value for each iteration of the computation loop prior to entering the time loop and save the values in an array. The increase in memory required to store the values is small in comparison to the large savings in time. The main loop in Code 8 is doubly nested. The inner loop includes a series of guarded computations; some are a function of the inner loop index but not the outer loop index while others are a function of the outer loop index but not the inner loop index for (j = 0; j < N; j++) { for (i = 0; i < M; i++) { r = i * hrmax; R = A[j]; temp = (PRM[3] == 0.0) ? 1.0 : pow(r, PRM[3]); high = temp * kcoeff * B[j] * PRM[2] * PRM[4]; low = high * PRM[6] * PRM[6] / (1.0 + pow(PRM[4] * PRM[6], 2.0)); kap = (R > PRM[6]) ? high * R * R / (1.0 + pow(PRM[4]*r, 2.0) : low * pow(R/PRM[6], PRM[5]); < rest of loop omitted > }} Note that the value of temp is invariant to j. Thus, we can hoist the computation for temp out of the loop and save its values in an array. for (i = 0; i < M; i++) { r = i * hrmax; TEMP[i] = pow(r, PRM[3]); } [N.B. – the case for PRM[3] = 0 is omitted and will be reintroduced later.] We now hoist out of the inner loop the computations invariant to i. Since the conditional guarding the value of kap is invariant to i, it behooves us to hoist the computation out of the inner loop, thereby executing the guard once rather than M times. The final version of the code is for (j = 0; j < N; j++) { R = rig[j] / 1000.; tmp1 = kcoeff * par[2] * beta[j] * par[4]; tmp2 = 1.0 + (par[4] * par[4] * par[6] * par[6]); tmp3 = 1.0 + (par[4] * par[4] * R * R); tmp4 = par[6] * par[6] / tmp2; tmp5 = R * R / tmp3; tmp6 = pow(R / par[6], par[5]); if ((par[3] == 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp5; } else if ((par[3] == 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * tmp4 * tmp6; } else if ((par[3] != 0.0) && (R > par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp5; } else if ((par[3] != 0.0) && (R <= par[6])) { for (i = 1; i <= imax1; i++) KAP[i] = tmp1 * TEMP[i] * tmp4 * tmp6; } for (i = 0; i < M; i++) { kap = KAP[i]; r = i * hrmax; < rest of loop omitted > } } Maybe not the prettiest piece of code, but certainly much more efficient than the original loop, Copy operations Several programs unnecessarily copy data from one data structure to another. This problem occurs in both Fortran and C programs, although it manifests itself differently in the two languages. Code 1 declares two arrays—one for old values and one for new values. At the end of each iteration, the array of new values is copied to the array of old values to reset the data structures for the next iteration. This problem occurs in Fortran programs not included in this study and in both Fortran 77 and Fortran 90 code. Introducing pointers to the arrays and swapping pointer values is an obvious way to eliminate the copying; but pointers is not a feature that many Fortran programmers know well or are comfortable using. An easy solution not involving pointers is to extend the dimension of the value array by 1 and use the last dimension to differentiate between arrays at different times. For example, if the data space is N x N, declare the array (N, N, 2). Then store the problem’s initial values in (_, _, 2) and define the scalar names new = 2 and old = 1. At the start of each iteration, swap old and new to reset the arrays. The old–new copy problem did not appear in any C program. In programs that had new and old values, the code swapped pointers to reset data structures. Where unnecessary coping did occur is in structure assignment and parameter passing. Structures in C are handled much like scalars. Assignment causes the data space of the right-hand name to be copied to the data space of the left-hand name. Similarly, when a structure is passed to a function, the data space of the actual parameter is copied to the data space of the formal parameter. If the structure is large and the assignment or function call is in an inner loop, then copying costs can grow quite large. While none of the ten programs considered here manifested this problem, it did occur in programs not included in the study. A simple fix is always to refer to structures via pointers. Optimizing loop structures Since scientific programs spend almost all their time in loops, efficient loops are the key to good performance. Conditionals, function calls, little instruction level parallelism, and large numbers of temporary values make it difficult for the compiler to generate tightly packed, highly efficient code. Conditionals and function calls introduce jumps that disrupt code flow. Users should eliminate or isolate conditionls to their own loops as much as possible. Often logical expressions can be substituted for if-then-else statements. For example, code 2 includes the following snippet MaxDelta = 0.0 do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) if (Delta > MaxDelta) MaxDelta = Delta enddo enddo if (MaxDelta .gt. 0.001) goto 200 Since the only use of MaxDelta is to control the jump to 200 and all that matters is whether or not it is greater than 0.001, I made MaxDelta a boolean and rewrote the snippet as MaxDelta = .false. do J = 1, N do I = 1, M < code omitted > Delta = abs(OldValue ? NewValue) MaxDelta = MaxDelta .or. (Delta .gt. 0.001) enddo enddo if (MaxDelta) goto 200 thereby, eliminating the conditional expression from the inner loop. A microprocessor can execute many instructions per instruction cycle. Typically, it can execute one or more memory, floating point, integer, and jump operations. To be executed simultaneously, the operations must be independent. Thick loops tend to have more instruction level parallelism than thin loops. Moreover, they reduce memory traffice by maximizing data reuse. Loop unrolling and loop fusion are two techniques to increase the size of loop bodies. Several of the codes studied benefitted from loop unrolling, but none benefitted from loop fusion. This observation is not too surpising since it is the general tendency of programmers to write thick loops. As loops become thicker, the number of temporary values grows, increasing register pressure. If registers spill, then memory traffic increases and code flow is disrupted. A thick loop with many temporary values may execute slower than an equivalent series of thin loops. The biggest gain will be achieved if the thick loop can be split into a series of independent loops eliminating the need to write and read temporary arrays. I found such an occasion in code 10 where I split the loop do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do into two disjoint loops do i = 1, n do j = 1, m A24(j,i)= S24(j,i) * T24(j,i) + S25(j,i) * U25(j,i) B24(j,i)= S24(j,i) * T25(j,i) + S25(j,i) * U24(j,i) A25(j,i)= S24(j,i) * C24(j,i) + S25(j,i) * V24(j,i) B25(j,i)= S24(j,i) * U25(j,i) + S25(j,i) * V25(j,i) end do end do do i = 1, n do j = 1, m C24(j,i)= S26(j,i) * T26(j,i) + S27(j,i) * U26(j,i) D24(j,i)= S26(j,i) * T27(j,i) + S27(j,i) * V26(j,i) C25(j,i)= S27(j,i) * S28(j,i) + S26(j,i) * U28(j,i) D25(j,i)= S27(j,i) * T28(j,i) + S26(j,i) * V28(j,i) end do end do Conclusions Over the course of the last year, I have had the opportunity to work with over two dozen academic scientific programmers at leading research universities. Their research interests span a broad range of scientific fields. Except for two programs that relied almost exclusively on library routines (matrix multiply and fast Fourier transform), I was able to improve significantly the single processor performance of all codes. Improvements range from 2x to 15.5x with a simple average of 4.75x. Changes to the source code were at a very high level. I did not use sophisticated techniques or programming tools to discover inefficiencies or effect the changes. Only one code was parallel despite the availability of parallel systems to all developers. Clearly, we have a problem—personal scientific research codes are highly inefficient and not running parallel. The developers are unaware of simple optimization techniques to make programs run faster. They lack education in the art of code optimization and parallel programming. I do not believe we can fix the problem by publishing additional books or training manuals. To date, the developers in questions have not studied the books or manual available, and are unlikely to do so in the future. Short courses are a possible solution, but I believe they are too concentrated to be much use. The general concepts can be taught in a three or four day course, but that is not enough time for students to practice what they learn and acquire the experience to apply and extend the concepts to their codes. Practice is the key to becoming proficient at optimization. I recommend that graduate students be required to take a semester length course in optimization and parallel programming. We would never give someone access to state-of-the-art scientific equipment costing hundreds of thousands of dollars without first requiring them to demonstrate that they know how to use the equipment. Yet the criterion for time on state-of-the-art supercomputers is at most an interesting project. Requestors are never asked to demonstrate that they know how to use the system, or can use the system effectively. A semester course would teach them the required skills. Government agencies that fund academic scientific research pay for most of the computer systems supporting scientific research as well as the development of most personal scientific codes. These agencies should require graduate schools to offer a course in optimization and parallel programming as a requirement for funding. About the Author John Feo received his Ph.D. in Computer Science from The University of Texas at Austin in 1986. After graduate school, Dr. Feo worked at Lawrence Livermore National Laboratory where he was the Group Leader of the Computer Research Group and principal investigator of the Sisal Language Project. In 1997, Dr. Feo joined Tera Computer Company where he was project manager for the MTA, and oversaw the programming and evaluation of the MTA at the San Diego Supercomputer Center. In 2000, Dr. Feo joined Sun Microsystems as an HPC application specialist. He works with university research groups to optimize and parallelize scientific codes. Dr. Feo has published over two dozen research articles in the areas of parallel parallel programming, parallel programming languages, and application performance.

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• Extending Oracle CEP with Predictive Analytics

  - by vikram.shukla(at)oracle.com

  Introduction: OCEP is often used as a business rules engine to execute a set of business logic rules via CQL statements, and take decisions based on the outcome of those rules. There are times where configuring rules manually is sufficient because an application needs to deal with only a small and well-defined set of static rules. However, in many situations customers don't want to pre-define such rules for two reasons. First, they are dealing with events with lots of columns and manually crafting such rules for each column or a set of columns and combinations thereof is almost impossible. Second, they are content with probabilistic outcomes and do not care about 100% precision. The former is the case when a user is dealing with data with high dimensionality, the latter when an application can live with "false" positives as they can be discarded after further inspection, say by a Human Task component in a Business Process Management software. The primary goal of this blog post is to show how this can be achieved by combining OCEP with Oracle Data Mining® and leveraging the latter's rich set of algorithms and functionality to do predictive analytics in real time on streaming events. The secondary goal of this post is also to show how OCEP can be extended to invoke any arbitrary external computation in an RDBMS from within CEP. The extensible facility is known as the JDBC cartridge. The rest of the post describes the steps required to achieve this: We use the dataset available at http://blogs.oracle.com/datamining/2010/01/fraud_and_anomaly_detection_made_simple.html to showcase the capabilities. We use it to show how transaction anomalies or fraud can be detected. Building the model: Follow the self-explanatory steps described at the above URL to build the model.  It is very simple - it uses built-in Oracle Data Mining PL/SQL packages to cleanse, normalize and build the model out of the dataset.  You can also use graphical Oracle Data Miner®  to build the models. To summarize, it involves: Specifying which algorithms to use. In this case we use Support Vector Machines as we're trying to find anomalies in highly dimensional dataset.Build model on the data in the table for the algorithms specified. For this example, the table was populated in the scott/tiger schema with appropriate privileges. Configuring the Data Source: This is the first step in building CEP application using such an integration.  Our datasource looks as follows in the server config file.  It is advisable that you use the Visualizer to add it to the running server dynamically, rather than manually edit the file.    <data-source>         <name>DataMining</name>         <data-source-params>             <jndi-names>                 <element>DataMining</element>             </jndi-names>             <global-transactions-protocol>OnePhaseCommit</global-transactions-protocol>         </data-source-params>         <connection-pool-params>             <credential-mapping-enabled></credential-mapping-enabled>             <test-table-name>SQL SELECT 1 from DUAL</test-table-name>             <initial-capacity>1</initial-capacity>             <max-capacity>15</max-capacity>             <capacity-increment>1</capacity-increment>         </connection-pool-params>         <driver-params>             <use-xa-data-source-interface>true</use-xa-data-source-interface>             <driver-name>oracle.jdbc.OracleDriver</driver-name>             <url>jdbc:oracle:thin:@localhost:1522:orcl</url>             <properties>                 <element>                     <value>scott</value>                     <name>user</name>                 </element>                 <element>                     <value>{Salted-3DES}AzFE5dDbO2g=</value>                     <name>password</name>                 </element>                                 <element>                     <name>com.bea.core.datasource.serviceName</name>                     <value>oracle11.2g</value>                 </element>                 <element>                     <name>com.bea.core.datasource.serviceVersion</name>                     <value>11.2.0</value>                 </element>                 <element>                     <name>com.bea.core.datasource.serviceObjectClass</name>                     <value>java.sql.Driver</value>                 </element>             </properties>         </driver-params>     </data-source>   Designing the EPN: The EPN is very simple in this example. We briefly describe each of the components. The adapter ("DataMiningAdapter") reads data from a .csv file and sends it to the CQL processor downstream. The event payload here is same as that of the table in the database (refer to the attached project or do a "desc table-name" from a SQL*PLUS prompt). While this is for convenience in this example, it need not be the case. One can still omit fields in the streaming events, and need not match all columns in the table on which the model was built. Better yet, it does not even need to have the same name as columns in the table, as long as you alias them in the USING clause of the mining function. (Caveat: they still need to draw values from a similar universe or domain, otherwise it constitutes incorrect usage of the model). There are two things in the CQL processor ("DataMiningProc") that make scoring possible on streaming events. 1.      User defined cartridge function Please refer to the OCEP CQL reference manual to find more details about how to define such functions. We include the function below in its entirety for illustration. <?xml version="1.0" encoding="UTF-8"?> <jdbcctxconfig:config     xmlns:jdbcctxconfig="http://www.bea.com/ns/wlevs/config/application"     xmlns:jc="http://www.oracle.com/ns/ocep/config/jdbc">        <jc:jdbc-ctx>         <name>Oracle11gR2</name>         <data-source>DataMining</data-source>               <function name="prediction2">                                 <param name="CQLMONTH" type="char"/>                      <param name="WEEKOFMONTH" type="int"/>                      <param name="DAYOFWEEK" type="char" />                      <param name="MAKE" type="char" />                      <param name="ACCIDENTAREA"   type="char" />                      <param name="DAYOFWEEKCLAIMED"  type="char" />                      <param name="MONTHCLAIMED" type="char" />                      <param name="WEEKOFMONTHCLAIMED" type="int" />                      <param name="SEX" type="char" />                      <param name="MARITALSTATUS"   type="char" />                      <param name="AGE" type="int" />                      <param name="FAULT" type="char" />                      <param name="POLICYTYPE"   type="char" />                      <param name="VEHICLECATEGORY"  type="char" />                      <param name="VEHICLEPRICE" type="char" />                      <param name="FRAUDFOUND" type="int" />                      <param name="POLICYNUMBER" type="int" />                      <param name="REPNUMBER" type="int" />                      <param name="DEDUCTIBLE"   type="int" />                      <param name="DRIVERRATING"  type="int" />                      <param name="DAYSPOLICYACCIDENT"   type="char" />                      <param name="DAYSPOLICYCLAIM" type="char" />                      <param name="PASTNUMOFCLAIMS" type="char" />                      <param name="AGEOFVEHICLES" type="char" />                      <param name="AGEOFPOLICYHOLDER" type="char" />                      <param name="POLICEREPORTFILED" type="char" />                      <param name="WITNESSPRESNT" type="char" />                      <param name="AGENTTYPE" type="char" />                      <param name="NUMOFSUPP" type="char" />                      <param name="ADDRCHGCLAIM"   type="char" />                      <param name="NUMOFCARS" type="char" />                      <param name="CQLYEAR" type="int" />                      <param name="BASEPOLICY" type="char" />                                     <return-component-type>char</return-component-type>                                                      <sql><![CDATA[             SELECT to_char(PREDICTION_PROBABILITY(CLAIMSMODEL, '0' USING *))               AS probability             FROM (SELECT  :CQLMONTH AS MONTH,                                            :WEEKOFMONTH AS WEEKOFMONTH,                          :DAYOFWEEK AS DAYOFWEEK,                           :MAKE AS MAKE,                           :ACCIDENTAREA AS ACCIDENTAREA,                           :DAYOFWEEKCLAIMED AS DAYOFWEEKCLAIMED,                           :MONTHCLAIMED AS MONTHCLAIMED,                           :WEEKOFMONTHCLAIMED,                             :SEX AS SEX,                           :MARITALSTATUS AS MARITALSTATUS,                            :AGE AS AGE,                           :FAULT AS FAULT,                           :POLICYTYPE AS POLICYTYPE,                            :VEHICLECATEGORY AS VEHICLECATEGORY,                           :VEHICLEPRICE AS VEHICLEPRICE,                           :FRAUDFOUND AS FRAUDFOUND,                           :POLICYNUMBER AS POLICYNUMBER,                           :REPNUMBER AS REPNUMBER,                           :DEDUCTIBLE AS DEDUCTIBLE,                            :DRIVERRATING AS DRIVERRATING,                           :DAYSPOLICYACCIDENT AS DAYSPOLICYACCIDENT,                            :DAYSPOLICYCLAIM AS DAYSPOLICYCLAIM,                           :PASTNUMOFCLAIMS AS PASTNUMOFCLAIMS,                           :AGEOFVEHICLES AS AGEOFVEHICLES,                           :AGEOFPOLICYHOLDER AS AGEOFPOLICYHOLDER,                           :POLICEREPORTFILED AS POLICEREPORTFILED,                           :WITNESSPRESNT AS WITNESSPRESENT,                           :AGENTTYPE AS AGENTTYPE,                           :NUMOFSUPP AS NUMOFSUPP,                           :ADDRCHGCLAIM AS ADDRCHGCLAIM,                            :NUMOFCARS AS NUMOFCARS,                           :CQLYEAR AS YEAR,                           :BASEPOLICY AS BASEPOLICY                 FROM dual)                 ]]>         </sql>        </function>     </jc:jdbc-ctx> </jdbcctxconfig:config> 2.      Invoking the function for each event. Once this function is defined, you can invoke it from CQL as follows: <?xml version="1.0" encoding="UTF-8"?> <wlevs:config xmlns:wlevs="http://www.bea.com/ns/wlevs/config/application">   <processor>     <name>DataMiningProc</name>     <rules>        <query id="q1"><![CDATA[                     ISTREAM(SELECT S.CQLMONTH,                                   S.WEEKOFMONTH,                                   S.DAYOFWEEK, S.MAKE,                                   :                                         S.BASEPOLICY,                                    C.F AS probability                                                 FROM                                 StreamDataChannel [NOW] AS S,                                 TABLE(prediction2@Oracle11gR2(S.CQLMONTH,                                      S.WEEKOFMONTH,                                      S.DAYOFWEEK,                                       S.MAKE, ...,                                      S.BASEPOLICY) AS F of char) AS C)                       ]]></query>                 </rules>               </processor>           </wlevs:config>   Finally, the last stage in the EPN prints out the probability of the event being an anomaly. One can also define a threshold in CQL to filter out events that are normal, i.e., below a certain mark as defined by the analyst or designer. Sample Runs: Now let's see how this behaves when events are streamed through CEP. We use only two events for brevity, one normal and other one not. This is one of the "normal" looking events and the probability of it being anomalous is less than 60%. Event is: eventType=DataMiningOutEvent object=q1  time=2904821976256 S.CQLMONTH=Dec, S.WEEKOFMONTH=5, S.DAYOFWEEK=Wednesday, S.MAKE=Honda, S.ACCIDENTAREA=Urban, S.DAYOFWEEKCLAIMED=Tuesday, S.MONTHCLAIMED=Jan, S.WEEKOFMONTHCLAIMED=1, S.SEX=Female, S.MARITALSTATUS=Single, S.AGE=21, S.FAULT=Policy Holder, S.POLICYTYPE=Sport - Liability, S.VEHICLECATEGORY=Sport, S.VEHICLEPRICE=more than 69000, S.FRAUDFOUND=0, S.POLICYNUMBER=1, S.REPNUMBER=12, S.DEDUCTIBLE=300, S.DRIVERRATING=1, S.DAYSPOLICYACCIDENT=more than 30, S.DAYSPOLICYCLAIM=more than 30, S.PASTNUMOFCLAIMS=none, S.AGEOFVEHICLES=3 years, S.AGEOFPOLICYHOLDER=26 to 30, S.POLICEREPORTFILED=No, S.WITNESSPRESENT=No, S.AGENTTYPE=External, S.NUMOFSUPP=none, S.ADDRCHGCLAIM=1 year, S.NUMOFCARS=3 to 4, S.CQLYEAR=1994, S.BASEPOLICY=Liability, probability=.58931702982118561 isTotalOrderGuarantee=true\nAnamoly probability: .58931702982118561 However, the following event is scored as an anomaly with a very high probability of  89%. So there is likely to be something wrong with it. A close look reveals that the value of "deductible" field (10000) is not "normal". What exactly constitutes normal here?. If you run the query on the database to find ALL distinct values for the "deductible" field, it returns the following set: {300, 400, 500, 700} Event is: eventType=DataMiningOutEvent object=q1  time=2598483773496 S.CQLMONTH=Dec, S.WEEKOFMONTH=5, S.DAYOFWEEK=Wednesday, S.MAKE=Honda, S.ACCIDENTAREA=Urban, S.DAYOFWEEKCLAIMED=Tuesday, S.MONTHCLAIMED=Jan, S.WEEKOFMONTHCLAIMED=1, S.SEX=Female, S.MARITALSTATUS=Single, S.AGE=21, S.FAULT=Policy Holder, S.POLICYTYPE=Sport - Liability, S.VEHICLECATEGORY=Sport, S.VEHICLEPRICE=more than 69000, S.FRAUDFOUND=0, S.POLICYNUMBER=1, S.REPNUMBER=12, S.DEDUCTIBLE=10000, S.DRIVERRATING=1, S.DAYSPOLICYACCIDENT=more than 30, S.DAYSPOLICYCLAIM=more than 30, S.PASTNUMOFCLAIMS=none, S.AGEOFVEHICLES=3 years, S.AGEOFPOLICYHOLDER=26 to 30, S.POLICEREPORTFILED=No, S.WITNESSPRESENT=No, S.AGENTTYPE=External, S.NUMOFSUPP=none, S.ADDRCHGCLAIM=1 year, S.NUMOFCARS=3 to 4, S.CQLYEAR=1994, S.BASEPOLICY=Liability, probability=.89171554529576691 isTotalOrderGuarantee=true\nAnamoly probability: .89171554529576691 Conclusion: By way of this example, we show: real-time scoring of events as they flow through CEP leveraging Oracle Data Mining.how CEP applications can invoke complex arbitrary external computations (function shipping) in an RDBMS.

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• Building a better mouse-trap &ndash; Improving the creation of XML Message Requests using Reflection, XML &amp; XSLT

  - by paulschapman

  Introduction The way I previously created messages to send to the GovTalk service I used the XMLDocument to create the request. While this worked it left a number of problems; not least that for every message a special function would need to created. This is OK for the short term but the biggest cost in any software project is maintenance and this would be a headache to maintain. So the following is a somewhat better way of achieving the same thing. For the purposes of this article I am going to be using the CompanyNumberSearch request of the GovTalk service – although this technique would work for any service that accepted XML. The C# functions which send and receive the messages remain the same. The magic sauce in this is the XSLT which defines the structure of the request, and the use of objects in conjunction with reflection to provide the content. It is a bit like Sweet Chilli Sauce added to Chicken on a bed of rice. So on to the Sweet Chilli Sauce The Sweet Chilli Sauce The request to search for a company based on it’s number is as follows; <GovTalkMessage xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" > <EnvelopeVersion>1.0</EnvelopeVersion> <Header> <MessageDetails> <Class>NumberSearch</Class> <Qualifier>request</Qualifier> <TransactionID>1</TransactionID> </MessageDetails> <SenderDetails> <IDAuthentication> <SenderID>????????????????????????????????</SenderID> <Authentication> <Method>CHMD5</Method> <Value>????????????????????????????????</Value> </Authentication> </IDAuthentication> </SenderDetails> </Header> <GovTalkDetails> <Keys/> </GovTalkDetails> <Body> <NumberSearchRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://xmlgw.companieshouse.gov.uk/v1-0/schema/NumberSearch.xsd"> <PartialCompanyNumber>99999999</PartialCompanyNumber> <DataSet>LIVE</DataSet> <SearchRows>1</SearchRows> </NumberSearchRequest> </Body> </GovTalkMessage> This is the XML that we send to the GovTalk Service and we get back a list of companies that match the criteria passed A message is structured in two parts; The envelope which identifies the person sending the request, with the name of the request, and the body which gives the detail of the company we are looking for. The Chilli What makes it possible is the use of XSLT to define the message – and serialization to convert each request object into XML. To start we need to create an object which will represent the contents of the message we are sending. However there is a common properties in all the messages that we send to Companies House. These properties are as follows SenderId – the id of the person sending the message SenderPassword – the password associated with Id TransactionId – Unique identifier for the message AuthenticationValue – authenticates the request Because these properties are unique to the Companies House message, and because they are shared with all messages they are perfect candidates for a base class. The class is as follows; using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Security.Cryptography; using System.Text; using System.Text.RegularExpressions; using Microsoft.WindowsAzure.ServiceRuntime; namespace CompanyHub.Services { public class GovTalkRequest { public GovTalkRequest() { try { SenderID = RoleEnvironment.GetConfigurationSettingValue("SenderId"); SenderPassword = RoleEnvironment.GetConfigurationSettingValue("SenderPassword"); TransactionId = DateTime.Now.Ticks.ToString(); AuthenticationValue = EncodePassword(String.Format("{0}{1}{2}", SenderID, SenderPassword, TransactionId)); } catch (System.Exception ex) { throw ex; } } /// <summary> /// returns the Sender ID to be used when communicating with the GovTalk Service /// </summary> public String SenderID { get; set; } /// <summary> /// return the password to be used when communicating with the GovTalk Service /// </summary> public String SenderPassword { get; set; } // end SenderPassword /// <summary> /// Transaction Id - uses the Time and Date converted to Ticks /// </summary> public String TransactionId { get; set; } // end TransactionId /// <summary> /// calculate the authentication value that will be used when /// communicating with /// </summary> public String AuthenticationValue { get; set; } // end AuthenticationValue property /// <summary> /// encodes password(s) using MD5 /// </summary> /// <param name="clearPassword"></param> /// <returns></returns> public static String EncodePassword(String clearPassword) { MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider(); byte[] hashedBytes; UTF32Encoding encoder = new UTF32Encoding(); hashedBytes = md5Hasher.ComputeHash(ASCIIEncoding.Default.GetBytes(clearPassword)); String result = Regex.Replace(BitConverter.ToString(hashedBytes), "-", "").ToLower(); return result; } } } There is nothing particularly clever here, except for the EncodePassword method which hashes the value made up of the SenderId, Password and Transaction id. Each message inherits from this object. So for the Company Number Search in addition to the properties above we need a partial number, which dataset to search – for the purposes of the project we only need to search the LIVE set so this can be set in the constructor and the SearchRows. Again all are set as properties. With the SearchRows and DataSet initialized in the constructor. public class CompanyNumberSearchRequest : GovTalkRequest, IDisposable { /// <summary> /// /// </summary> public CompanyNumberSearchRequest() : base() { DataSet = "LIVE"; SearchRows = 1; } /// <summary> /// Company Number to search against /// </summary> public String PartialCompanyNumber { get; set; } /// <summary> /// What DataSet should be searched for the company /// </summary> public String DataSet { get; set; } /// <summary> /// How many rows should be returned /// </summary> public int SearchRows { get; set; } public void Dispose() { DataSet = String.Empty; PartialCompanyNumber = String.Empty; DataSet = "LIVE"; SearchRows = 1; } } As well as inheriting from our base class, I have also inherited from IDisposable – not just because it is just plain good practice to dispose of objects when coding, but it gives also gives us more versatility when using the object. There are four stages in making a request and this is reflected in the four methods we execute in making a call to the Companies House service; Create a request Send a request Check the status If OK then get the results of the request I’ve implemented each of these stages within a static class called Toolbox – which also means I don’t need to create an instance of the class to use it. When making a request there are three stages; Get the template for the message Serialize the object representing the message Transform the serialized object using a predefined XSLT file. Each of my templates I have defined as an embedded resource. When retrieving a resource of this kind we have to include the full namespace to the resource. In making the code re-usable as much as possible I defined the full ‘path’ within the GetRequest method. requestFile = String.Format("CompanyHub.Services.Schemas.{0}", RequestFile); So we now have the full path of the file within the assembly. Now all we need do is retrieve the assembly and get the resource. asm = Assembly.GetExecutingAssembly(); sr = asm.GetManifestResourceStream(requestFile); Once retrieved  So this can be returned to the calling function and we now have a stream of XSLT to define the message. Time now to serialize the request to create the other side of this message. // Serialize object containing Request, Load into XML Document t = Obj.GetType(); ms = new MemoryStream(); serializer = new XmlSerializer(t); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); serializer.Serialize(xmlTextWriter, Obj); ms = (MemoryStream)xmlTextWriter.BaseStream; GovTalkRequest = Toolbox.ConvertByteArrayToString(ms.ToArray()); First off we need the type of the object so we make a call to the GetType method of the object containing the Message properties. Next we need a MemoryStream, XmlSerializer and an XMLTextWriter so these can be initialized. The object is serialized by making the call to the Serialize method of the serializer object. The result of that is then converted into a MemoryStream. That MemoryStream is then converted into a string. ConvertByteArrayToString This is a fairly simple function which uses an ASCIIEncoding object found within the System.Text namespace to convert an array of bytes into a string. public static String ConvertByteArrayToString(byte[] bytes) { System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding(); return enc.GetString(bytes); } I only put it into a function because I will be using this in various places. The Sauce When adding support for other messages outside of creating a new object to store the properties of the message, the C# components do not need to change. It is in the XSLT file that the versatility of the technique lies. The XSLT file determines the format of the message. For the CompanyNumberSearch the XSLT file is as follows; <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:template match="/"> <GovTalkMessage xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" > <EnvelopeVersion>1.0</EnvelopeVersion> <Header> <MessageDetails> <Class>NumberSearch</Class> <Qualifier>request</Qualifier> <TransactionID> <xsl:value-of select="CompanyNumberSearchRequest/TransactionId"/> </TransactionID> </MessageDetails> <SenderDetails> <IDAuthentication> <SenderID><xsl:value-of select="CompanyNumberSearchRequest/SenderID"/></SenderID> <Authentication> <Method>CHMD5</Method> <Value> <xsl:value-of select="CompanyNumberSearchRequest/AuthenticationValue"/> </Value> </Authentication> </IDAuthentication> </SenderDetails> </Header> <GovTalkDetails> <Keys/> </GovTalkDetails> <Body> <NumberSearchRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://xmlgw.companieshouse.gov.uk/v1-0/schema/NumberSearch.xsd"> <PartialCompanyNumber> <xsl:value-of select="CompanyNumberSearchRequest/PartialCompanyNumber"/> </PartialCompanyNumber> <DataSet> <xsl:value-of select="CompanyNumberSearchRequest/DataSet"/> </DataSet> <SearchRows> <xsl:value-of select="CompanyNumberSearchRequest/SearchRows"/> </SearchRows> </NumberSearchRequest> </Body> </GovTalkMessage> </xsl:template> </xsl:stylesheet> The outer two tags define that this is a XSLT stylesheet and the root tag from which the nodes are searched for. The GovTalkMessage is the format of the message that will be sent to Companies House. We first set up the XslCompiledTransform object which will transform the XSLT template and the serialized object into the request to Companies House. xslt = new XslCompiledTransform(); resultStream = new MemoryStream(); writer = new XmlTextWriter(resultStream, Encoding.ASCII); doc = new XmlDocument(); The Serialize method require XmlTextWriter to write the XML (writer) and a stream to place the transferred object into (writer). The XML will be loaded into an XMLDocument object (doc) prior to the transformation. // create XSLT Template xslTemplate = Toolbox.GetRequest(Template); xslTemplate.Seek(0, SeekOrigin.Begin); templateReader = XmlReader.Create(xslTemplate); xslt.Load(templateReader); I have stored all the templates as a series of Embedded Resources and the GetRequestCall takes the name of the template and extracts the relevent XSLT file. /// <summary> /// Gets the framwork XML which makes the request /// </summary> /// <param name="RequestFile"></param> /// <returns></returns> public static Stream GetRequest(String RequestFile) { String requestFile = String.Empty; Stream sr = null; Assembly asm = null; try { requestFile = String.Format("CompanyHub.Services.Schemas.{0}", RequestFile); asm = Assembly.GetExecutingAssembly(); sr = asm.GetManifestResourceStream(requestFile); } catch (Exception) { throw; } finally { asm = null; } return sr; } // end private static stream GetRequest We first take the template name and expand it to include the full namespace to the Embedded Resource I like to keep all my schemas in the same directory and so the namespace reflects this. The rest is the default namespace for the project. Then we get the currently executing assembly (which will contain the resources with the call to GetExecutingAssembly() ) Finally we get a stream which contains the XSLT file. We use this stream and then load an XmlReader with the contents of the template, and that is in turn loaded into the XslCompiledTransform object. We convert the object containing the message properties into Xml by serializing it; calling the Serialize() method of the XmlSerializer object. To set up the object we do the following; t = Obj.GetType(); ms = new MemoryStream(); serializer = new XmlSerializer(t); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); We first determine the type of the object being transferred by calling GetType() We create an XmlSerializer object by passing the type of the object being serialized. The serializer writes to a memory stream and that is linked to an XmlTextWriter. Next job is to serialize the object and load it into an XmlDocument. serializer.Serialize(xmlTextWriter, Obj); ms = (MemoryStream)xmlTextWriter.BaseStream; xmlRequest = new XmlTextReader(ms); GovTalkRequest = Toolbox.ConvertByteArrayToString(ms.ToArray()); doc.LoadXml(GovTalkRequest); Time to transform the XML to construct the full request. xslt.Transform(doc, writer); resultStream.Seek(0, SeekOrigin.Begin); request = Toolbox.ConvertByteArrayToString(resultStream.ToArray()); So that creates the full request to be sent  to Companies House. Sending the request So far we have a string with a request for the Companies House service. Now we need to send the request to the Companies House Service. Configuration within an Azure project There are entire blog entries written about configuration within an Azure project – most of this is out of scope for this article but the following is a summary. Configuration is defined in two files within the parent project *.csdef which contains the definition of configuration setting. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="OnlineCompanyHub" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition"> <WebRole name="CompanyHub.Host"> <InputEndpoints> <InputEndpoint name="HttpIn" protocol="http" port="80" /> </InputEndpoints> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> <Setting name="DataConnectionString" /> </ConfigurationSettings> </WebRole> <WebRole name="CompanyHub.Services"> <InputEndpoints> <InputEndpoint name="HttpIn" protocol="http" port="8080" /> </InputEndpoints> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> <Setting name="SenderId"/> <Setting name="SenderPassword" /> <Setting name="GovTalkUrl"/> </ConfigurationSettings> </WebRole> <WorkerRole name="CompanyHub.Worker"> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> </ConfigurationSettings> </WorkerRole> </ServiceDefinition>   Above is the configuration definition from the project. What we are interested in however is the ConfigurationSettings tag of the CompanyHub.Services WebRole. There are four configuration settings here, but at the moment we are interested in the second to forth settings; SenderId, SenderPassword and GovTalkUrl The value of these settings are defined in the ServiceDefinition.cscfg file; <?xml version="1.0"?> <ServiceConfiguration serviceName="OnlineCompanyHub" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration"> <Role name="CompanyHub.Host"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="DataConnectionString" value="UseDevelopmentStorage=true" /> </ConfigurationSettings> </Role> <Role name="CompanyHub.Services"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="SenderId" value="UserID"/> <Setting name="SenderPassword" value="Password"/> <Setting name="GovTalkUrl" value="http://xmlgw.companieshouse.gov.uk/v1-0/xmlgw/Gateway"/> </ConfigurationSettings> </Role> <Role name="CompanyHub.Worker"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> </ConfigurationSettings> </Role> </ServiceConfiguration>   Look for the Role tag that contains our project name (CompanyHub.Services). Having configured the parameters we can now transmit the request. This is done by ‘POST’ing a stream of XML to the Companies House servers. govTalkUrl = RoleEnvironment.GetConfigurationSettingValue("GovTalkUrl"); request = WebRequest.Create(govTalkUrl); request.Method = "POST"; request.ContentType = "text/xml"; writer = new StreamWriter(request.GetRequestStream()); writer.WriteLine(RequestMessage); writer.Close(); We use the WebRequest object to send the object. Set the method of sending to ‘POST’ and the type of data as text/xml. Once set up all we do is write the request to the writer – this sends the request to Companies House. Did the Request Work Part I – Getting the response Having sent a request – we now need the result of that request. response = request.GetResponse(); reader = response.GetResponseStream(); result = Toolbox.ConvertByteArrayToString(Toolbox.ReadFully(reader));   The WebRequest object has a GetResponse() method which allows us to get the response sent back. Like many of these calls the results come in the form of a stream which we convert into a string. Did the Request Work Part II – Translating the Response Much like XSLT and XML were used to create the original request, so it can be used to extract the response and by deserializing the result we create an object that contains the response. Did it work? It would be really great if everything worked all the time. Of course if it did then I don’t suppose people would pay me and others the big bucks so that our programmes do not a) Collapse in a heap (this is an area of memory) b) Blow every fuse in the place in a shower of sparks (this will probably not happen this being real life and not a Hollywood movie, but it was possible to blow the sound system of a BBC Model B with a poorly coded setting) c) Go nuts and trap everyone outside the airlock (this was from a movie, and unless NASA get a manned moon/mars mission set up unlikely to happen) d) Go nuts and take over the world (this was also from a movie, but please note life has a habit of being of exceeding the wildest imaginations of Hollywood writers (note writers – Hollywood executives have no imagination and judging by recent output of that town have turned plagiarism into an art form). e) Freeze in total confusion because the cleaner pulled the plug to the internet router (this has happened) So anyway – we need to check to see if our request actually worked. Within the GovTalk response there is a section that details the status of the message and a description of what went wrong (if anything did). I have defined an XSLT template which will extract these into an XML document. <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ev="http://www.govtalk.gov.uk/CM/envelope" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <xsl:template match="/"> <GovTalkStatus xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Status> <xsl:value-of select="ev:GovTalkMessage/ev:Header/ev:MessageDetails/ev:Qualifier"/> </Status> <Text> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Text"/> </Text> <Location> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Location"/> </Location> <Number> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Number"/> </Number> <Type> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Type"/> </Type> </GovTalkStatus> </xsl:template> </xsl:stylesheet>   Only thing different about previous XSL files is the references to two namespaces ev & gt. These are defined in the GovTalk response at the top of the response; xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" If we do not put these references into the XSLT template then  the XslCompiledTransform object will not be able to find the relevant tags. Deserialization is a fairly simple activity. encoder = new ASCIIEncoding(); ms = new MemoryStream(encoder.GetBytes(statusXML)); serializer = new XmlSerializer(typeof(GovTalkStatus)); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); messageStatus = (GovTalkStatus)serializer.Deserialize(ms);   We set up a serialization object using the object type containing the error state and pass to it the results of a transformation between the XSLT above and the GovTalk response. Now we have an object containing any error state, and the error message. All we need to do is check the status. If there is an error then we can flag an error. If not then  we extract the results and pass that as an object back to the calling function. We go this by guess what – defining an XSLT template for the result and using that to create an Xml Stream which can be deserialized into a .Net object. In this instance the XSLT to create the result of a Company Number Search is; <?xml version="1.0" encoding="us-ascii"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ev="http://www.govtalk.gov.uk/CM/envelope" xmlns:sch="http://xmlgw.companieshouse.gov.uk/v1-0/schema" exclude-result-prefixes="ev"> <xsl:template match="/"> <CompanySearchResult xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <CompanyNumber> <xsl:value-of select="ev:GovTalkMessage/ev:Body/sch:NumberSearch/sch:CoSearchItem/sch:CompanyNumber"/> </CompanyNumber> <CompanyName> <xsl:value-of select="ev:GovTalkMessage/ev:Body/sch:NumberSearch/sch:CoSearchItem/sch:CompanyName"/> </CompanyName> </CompanySearchResult> </xsl:template> </xsl:stylesheet> and the object definition is; using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace CompanyHub.Services { public class CompanySearchResult { public CompanySearchResult() { CompanyNumber = String.Empty; CompanyName = String.Empty; } public String CompanyNumber { get; set; } public String CompanyName { get; set; } } } Our entire code to make calls to send a request, and interpret the results are; String request = String.Empty; String response = String.Empty; GovTalkStatus status = null; fault = null; try { using (CompanyNumberSearchRequest requestObj = new CompanyNumberSearchRequest()) { requestObj.PartialCompanyNumber = CompanyNumber; request = Toolbox.CreateRequest(requestObj, "CompanyNumberSearch.xsl"); response = Toolbox.SendGovTalkRequest(request); status = Toolbox.GetMessageStatus(response); if (status.Status.ToLower() == "error") { fault = new HubFault() { Message = status.Text }; } else { Object obj = Toolbox.GetGovTalkResponse(response, "CompanyNumberSearchResult.xsl", typeof(CompanySearchResult)); } } } catch (FaultException<ArgumentException> ex) { fault = new HubFault() { FaultType = ex.Detail.GetType().FullName, Message = ex.Detail.Message }; } catch (System.Exception ex) { fault = new HubFault() { FaultType = ex.GetType().FullName, Message = ex.Message }; } finally { } Wrap up So there we have it – a reusable set of functions to send and interpret XML results from an internet based service. The code is reusable with a little change with any service which uses XML as a transport mechanism – and as for the Companies House GovTalk service all I need to do is create various objects for the result and message sent and the relevent XSLT files. I might need minor changes for other services but something like 70-90% will be exactly the same.

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• Using R to Analyze G1GC Log Files

  - by user12620111

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  Using R to Analyze G1GC Log Files   Using R to Analyze G1GC Log Files Introduction Working in Oracle Platform Integration gives an engineer opportunities to work on a wide array of technologies. My team’s goal is to make Oracle applications run best on the Solaris/SPARC platform. When looking for bottlenecks in a modern applications, one needs to be aware of not only how the CPUs and operating system are executing, but also network, storage, and in some cases, the Java Virtual Machine. I was recently presented with about 1.5 GB of Java Garbage First Garbage Collector log file data. If you’re not familiar with the subject, you might want to review Garbage First Garbage Collector Tuning by Monica Beckwith. The customer had been running Java HotSpot 1.6.0_31 to host a web application server. I was told that the Solaris/SPARC server was running a Java process launched using a commmand line that included the following flags: -d64 -Xms9g -Xmx9g -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:InitiatingHeapOccupancyPercent=80 -XX:PermSize=256m -XX:MaxPermSize=256m -XX:+PrintGC -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC -XX:+PrintGCDateStamps -XX:+PrintFlagsFinal -XX:+DisableExplicitGC -XX:+UnlockExperimentalVMOptions -XX:ParallelGCThreads=8 Several sources on the internet indicate that if I were to print out the 1.5 GB of log files, it would require enough paper to fill the bed of a pick up truck. Of course, it would be fruitless to try to scan the log files by hand. Tools will be required to summarize the contents of the log files. Others have encountered large Java garbage collection log files. There are existing tools to analyze the log files: IBM’s GC toolkit The chewiebug GCViewer gchisto HPjmeter Instead of using one of the other tools listed, I decide to parse the log files with standard Unix tools, and analyze the data with R. Data Cleansing The log files arrived in two different formats. I guess that the difference is that one set of log files was generated using a more verbose option, maybe -XX:+PrintHeapAtGC, and the other set of log files was generated without that option. Format 1 In some of the log files, the log files with the less verbose format, a single trace, i.e. the report of a singe garbage collection event, looks like this: {Heap before GC invocations=12280 (full 61): garbage-first heap total 9437184K, used 7499918K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 1 young (4096K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. 2014-05-14T07:24:00.988-0700: 60586.353: [GC pause (young) 7324M->7320M(9216M), 0.1567265 secs] Heap after GC invocations=12281 (full 61): garbage-first heap total 9437184K, used 7496533K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 0 young (0K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. } A simple grep can be used to extract a summary: $ grep "\[ GC pause (young" g1gc.log 2014-05-13T13:24:35.091-0700: 3.109: [GC pause (young) 20M->5029K(9216M), 0.0146328 secs] 2014-05-13T13:24:35.440-0700: 3.459: [GC pause (young) 9125K->6077K(9216M), 0.0086723 secs] 2014-05-13T13:24:37.581-0700: 5.599: [GC pause (young) 25M->8470K(9216M), 0.0203820 secs] 2014-05-13T13:24:42.686-0700: 10.704: [GC pause (young) 44M->15M(9216M), 0.0288848 secs] 2014-05-13T13:24:48.941-0700: 16.958: [GC pause (young) 51M->20M(9216M), 0.0491244 secs] 2014-05-13T13:24:56.049-0700: 24.066: [GC pause (young) 92M->26M(9216M), 0.0525368 secs] 2014-05-13T13:25:34.368-0700: 62.383: [GC pause (young) 602M->68M(9216M), 0.1721173 secs] But that format wasn't easily read into R, so I needed to be a bit more tricky. I used the following Unix command to create a summary file that was easy for R to read. $ echo "SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime" $ grep "\[GC pause (young" g1gc.log | grep -v mark | sed -e 's/[A-SU-z\(\),]/ /g' -e 's/->/ /' -e 's/: / /g' | more SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime 2014-05-13T13:24:35.091-0700 3.109 20 5029 9216 0.0146328 2014-05-13T13:24:35.440-0700 3.459 9125 6077 9216 0.0086723 2014-05-13T13:24:37.581-0700 5.599 25 8470 9216 0.0203820 2014-05-13T13:24:42.686-0700 10.704 44 15 9216 0.0288848 2014-05-13T13:24:48.941-0700 16.958 51 20 9216 0.0491244 2014-05-13T13:24:56.049-0700 24.066 92 26 9216 0.0525368 2014-05-13T13:25:34.368-0700 62.383 602 68 9216 0.1721173 Format 2 In some of the log files, the log files with the more verbose format, a single trace, i.e. the report of a singe garbage collection event, was more complicated than Format 1. Here is a text file with an example of a single G1GC trace in the second format. As you can see, it is quite complicated. It is nice that there is so much information available, but the level of detail can be overwhelming. I wrote this awk script (download) to summarize each trace on a single line. #!/usr/bin/env awk -f BEGIN { printf("SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize\n") } ###################### # Save count data from lines that are at the start of each G1GC trace. # Each trace starts out like this: # {Heap before GC invocations=14 (full 0): # garbage-first heap total 9437184K, used 325496K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) ###################### /{Heap.*full/{ gsub ( "\\)" , "" ); nf=split($0,a,"="); split(a[2],b," "); getline; if ( match($0, "first") ) { G1GC=1; IncrementalCount=b[1]; FullCount=substr( b[3], 1, length(b[3])-1 ); } else { G1GC=0; } } ###################### # Pull out time stamps that are in lines with this format: # 2014-05-12T14:02:06.025-0700: 94.312: [GC pause (young), 0.08870154 secs] ###################### /GC pause/ { DateTime=$1; SecondsSinceLaunch=substr($2, 1, length($2)-1); } ###################### # Heap sizes are in lines that look like this: # [ 4842M->4838M(9216M)] ###################### /\[ .*]$/ { gsub ( "\\[" , "" ); gsub ( "\ \]" , "" ); gsub ( "->" , " " ); gsub ( "\\( " , " " ); gsub ( "\ \)" , " " ); split($0,a," "); if ( split(a[1],b,"M") > 1 ) {BeforeSize=b[1]*1024;} if ( split(a[1],b,"K") > 1 ) {BeforeSize=b[1];} if ( split(a[2],b,"M") > 1 ) {AfterSize=b[1]*1024;} if ( split(a[2],b,"K") > 1 ) {AfterSize=b[1];} if ( split(a[3],b,"M") > 1 ) {TotalSize=b[1]*1024;} if ( split(a[3],b,"K") > 1 ) {TotalSize=b[1];} } ###################### # Emit an output line when you find input that looks like this: # [Times: user=1.41 sys=0.08, real=0.24 secs] ###################### /\[Times/ { if (G1GC==1) { gsub ( "," , "" ); split($2,a,"="); UserTime=a[2]; split($3,a,"="); SysTime=a[2]; split($4,a,"="); RealTime=a[2]; print DateTime,SecondsSinceLaunch,IncrementalCount,FullCount,UserTime,SysTime,RealTime,BeforeSize,AfterSize,TotalSize; G1GC=0; } } The resulting summary is about 25X smaller that the original file, but still difficult for a human to digest. SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ... 2014-05-12T18:36:34.669-0700: 3985.744 561 0 0.57 0.06 0.16 1724416 1720320 9437184 2014-05-12T18:36:34.839-0700: 3985.914 562 0 0.51 0.06 0.19 1724416 1720320 9437184 2014-05-12T18:36:35.069-0700: 3986.144 563 0 0.60 0.04 0.27 1724416 1721344 9437184 2014-05-12T18:36:35.354-0700: 3986.429 564 0 0.33 0.04 0.09 1725440 1722368 9437184 2014-05-12T18:36:35.545-0700: 3986.620 565 0 0.58 0.04 0.17 1726464 1722368 9437184 2014-05-12T18:36:35.726-0700: 3986.801 566 0 0.43 0.05 0.12 1726464 1722368 9437184 2014-05-12T18:36:35.856-0700: 3986.930 567 0 0.30 0.04 0.07 1726464 1723392 9437184 2014-05-12T18:36:35.947-0700: 3987.023 568 0 0.61 0.04 0.26 1727488 1723392 9437184 2014-05-12T18:36:36.228-0700: 3987.302 569 0 0.46 0.04 0.16 1731584 1724416 9437184 Reading the Data into R Once the GC log data had been cleansed, either by processing the first format with the shell script, or by processing the second format with the awk script, it was easy to read the data into R. g1gc.df = read.csv("summary.txt", row.names = NULL, stringsAsFactors=FALSE,sep="") str(g1gc.df) ## 'data.frame': 8307 obs. of 10 variables: ## $ row.names : chr "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ... ## $ SecondsSinceLaunch: num 1.16 1.47 1.97 3.83 6.1 ... ## $ IncrementalCount : int 0 1 2 3 4 5 6 7 8 9 ... ## $ FullCount : int 0 0 0 0 0 0 0 0 0 0 ... ## $ UserTime : num 0.11 0.05 0.04 0.21 0.08 0.26 0.31 0.33 0.34 0.56 ... ## $ SysTime : num 0.04 0.01 0.01 0.05 0.01 0.06 0.07 0.06 0.07 0.09 ... ## $ RealTime : num 0.02 0.02 0.01 0.04 0.02 0.04 0.05 0.04 0.04 0.06 ... ## $ BeforeSize : int 8192 5496 5768 22528 24576 43008 34816 53248 55296 93184 ... ## $ AfterSize : int 1400 1672 2557 4907 7072 14336 16384 18432 19456 21504 ... ## $ TotalSize : int 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 ... head(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount ## 1 2014-05-12T14:00:32.868-0700: 1.161 0 ## 2 2014-05-12T14:00:33.179-0700: 1.472 1 ## 3 2014-05-12T14:00:33.677-0700: 1.969 2 ## 4 2014-05-12T14:00:35.538-0700: 3.830 3 ## 5 2014-05-12T14:00:37.811-0700: 6.103 4 ## 6 2014-05-12T14:00:41.428-0700: 9.720 5 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 1 0 0.11 0.04 0.02 8192 1400 9437184 ## 2 0 0.05 0.01 0.02 5496 1672 9437184 ## 3 0 0.04 0.01 0.01 5768 2557 9437184 ## 4 0 0.21 0.05 0.04 22528 4907 9437184 ## 5 0 0.08 0.01 0.02 24576 7072 9437184 ## 6 0 0.26 0.06 0.04 43008 14336 9437184 Basic Statistics Once the data has been read into R, simple statistics are very easy to generate. All of the numbers from high school statistics are available via simple commands. For example, generate a summary of every column: summary(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount FullCount ## Length:8307 Min. : 1 Min. : 0 Min. : 0.0 ## Class :character 1st Qu.: 9977 1st Qu.:2048 1st Qu.: 0.0 ## Mode :character Median :12855 Median :4136 Median : 12.0 ## Mean :12527 Mean :4156 Mean : 31.6 ## 3rd Qu.:15758 3rd Qu.:6262 3rd Qu.: 61.0 ## Max. :55484 Max. :8391 Max. :113.0 ## UserTime SysTime RealTime BeforeSize ## Min. :0.040 Min. :0.0000 Min. : 0.0 Min. : 5476 ## 1st Qu.:0.470 1st Qu.:0.0300 1st Qu.: 0.1 1st Qu.:5137920 ## Median :0.620 Median :0.0300 Median : 0.1 Median :6574080 ## Mean :0.751 Mean :0.0355 Mean : 0.3 Mean :5841855 ## 3rd Qu.:0.920 3rd Qu.:0.0400 3rd Qu.: 0.2 3rd Qu.:7084032 ## Max. :3.370 Max. :1.5600 Max. :488.1 Max. :8696832 ## AfterSize TotalSize ## Min. : 1380 Min. :9437184 ## 1st Qu.:5002752 1st Qu.:9437184 ## Median :6559744 Median :9437184 ## Mean :5785454 Mean :9437184 ## 3rd Qu.:7054336 3rd Qu.:9437184 ## Max. :8482816 Max. :9437184 Q: What is the total amount of User CPU time spent in garbage collection? sum(g1gc.df$UserTime) ## [1] 6236 As you can see, less than two hours of CPU time was spent in garbage collection. Is that too much? To find the percentage of time spent in garbage collection, divide the number above by total_elapsed_time*CPU_count. In this case, there are a lot of CPU’s and it turns out the the overall amount of CPU time spent in garbage collection isn’t a problem when viewed in isolation. When calculating rates, i.e. events per unit time, you need to ask yourself if the rate is homogenous across the time period in the log file. Does the log file include spikes of high activity that should be separately analyzed? Averaging in data from nights and weekends with data from business hours may alias problems. If you have a reason to suspect that the garbage collection rates include peaks and valleys that need independent analysis, see the “Time Series” section, below. Q: How much garbage is collected on each pass? The amount of heap space that is recovered per GC pass is surprisingly low: At least one collection didn’t recover any data. (“Min.=0”) 25% of the passes recovered 3MB or less. (“1st Qu.=3072”) Half of the GC passes recovered 4MB or less. (“Median=4096”) The average amount recovered was 56MB. (“Mean=56390”) 75% of the passes recovered 36MB or less. (“3rd Qu.=36860”) At least one pass recovered 2GB. (“Max.=2121000”) g1gc.df$Delta = g1gc.df$BeforeSize - g1gc.df$AfterSize summary(g1gc.df$Delta) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0 3070 4100 56400 36900 2120000 Q: What is the maximum User CPU time for a single collection? The worst garbage collection (“Max.”) is many standard deviations away from the mean. The data appears to be right skewed. summary(g1gc.df$UserTime) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0.040 0.470 0.620 0.751 0.920 3.370 sd(g1gc.df$UserTime) ## [1] 0.3966 Basic Graphics Once the data is in R, it is trivial to plot the data with formats including dot plots, line charts, bar charts (simple, stacked, grouped), pie charts, boxplots, scatter plots histograms, and kernel density plots. Histogram of User CPU Time per Collection I don't think that this graph requires any explanation. hist(g1gc.df$UserTime, main="User CPU Time per Collection", xlab="Seconds", ylab="Frequency") Box plot to identify outliers When the initial data is viewed with a box plot, you can see the one crazy outlier in the real time per GC. Save this data point for future analysis and drop the outlier so that it’s not throwing off our statistics. Now the box plot shows many outliers, which will be examined later, using times series analysis. Notice that the scale of the x-axis changes drastically once the crazy outlier is removed. par(mfrow=c(2,1)) boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(dominated by a crazy outlier)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") crazy.outlier.df=g1gc.df[g1gc.df$RealTime > 400,] g1gc.df=g1gc.df[g1gc.df$RealTime < 400,] boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(crazy outlier excluded)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") box(which = "outer", lty = "solid") Here is the crazy outlier for future analysis: crazy.outlier.df ## row.names SecondsSinceLaunch IncrementalCount ## 8233 2014-05-12T23:15:43.903-0700: 20741 8316 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 8233 112 0.55 0.42 488.1 8381440 8235008 9437184 ## Delta ## 8233 146432 R Time Series Data To analyze the garbage collection as a time series, I’ll use Z’s Ordered Observations (zoo). “zoo is the creator for an S3 class of indexed totally ordered observations which includes irregular time series.” require(zoo) ## Loading required package: zoo ## ## Attaching package: 'zoo' ## ## The following objects are masked from 'package:base': ## ## as.Date, as.Date.numeric head(g1gc.df[,1]) ## [1] "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" ## [3] "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ## [5] "2014-05-12T14:00:37.811-0700:" "2014-05-12T14:00:41.428-0700:" options("digits.secs"=3) times=as.POSIXct( g1gc.df[,1], format="%Y-%m-%dT%H:%M:%OS%z:") g1gc.z = zoo(g1gc.df[,-c(1)], order.by=times) head(g1gc.z) ## SecondsSinceLaunch IncrementalCount FullCount ## 2014-05-12 17:00:32.868 1.161 0 0 ## 2014-05-12 17:00:33.178 1.472 1 0 ## 2014-05-12 17:00:33.677 1.969 2 0 ## 2014-05-12 17:00:35.538 3.830 3 0 ## 2014-05-12 17:00:37.811 6.103 4 0 ## 2014-05-12 17:00:41.427 9.720 5 0 ## UserTime SysTime RealTime BeforeSize AfterSize ## 2014-05-12 17:00:32.868 0.11 0.04 0.02 8192 1400 ## 2014-05-12 17:00:33.178 0.05 0.01 0.02 5496 1672 ## 2014-05-12 17:00:33.677 0.04 0.01 0.01 5768 2557 ## 2014-05-12 17:00:35.538 0.21 0.05 0.04 22528 4907 ## 2014-05-12 17:00:37.811 0.08 0.01 0.02 24576 7072 ## 2014-05-12 17:00:41.427 0.26 0.06 0.04 43008 14336 ## TotalSize Delta ## 2014-05-12 17:00:32.868 9437184 6792 ## 2014-05-12 17:00:33.178 9437184 3824 ## 2014-05-12 17:00:33.677 9437184 3211 ## 2014-05-12 17:00:35.538 9437184 17621 ## 2014-05-12 17:00:37.811 9437184 17504 ## 2014-05-12 17:00:41.427 9437184 28672 Example of Two Benchmark Runs in One Log File The data in the following graph is from a different log file, not the one of primary interest to this article. I’m including this image because it is an example of idle periods followed by busy periods. It would be uninteresting to average the rate of garbage collection over the entire log file period. More interesting would be the rate of garbage collect in the two busy periods. Are they the same or different? Your production data may be similar, for example, bursts when employees return from lunch and idle times on weekend evenings, etc. Once the data is in an R Time Series, you can analyze isolated time windows. Clipping the Time Series data Flashing back to our test case… Viewing the data as a time series is interesting. You can see that the work intensive time period is between 9:00 PM and 3:00 AM. Lets clip the data to the interesting period:     par(mfrow=c(2,1)) plot(g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Complete Log File", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") clipped.g1gc.z=window(g1gc.z, start=as.POSIXct("2014-05-12 21:00:00"), end=as.POSIXct("2014-05-13 03:00:00")) plot(clipped.g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Limited to Benchmark Execution", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") box(which = "outer", lty = "solid") Cumulative Incremental and Full GC count Here is the cumulative incremental and full GC count. When the line is very steep, it indicates that the GCs are repeating very quickly. Notice that the scale on the Y axis is different for full vs. incremental. plot(clipped.g1gc.z[,c(2:3)], main="Cumulative Incremental and Full GC count", xlab="Time of Day", col="#1b9e77") GC Analysis of Benchmark Execution using Time Series data In the following series of 3 graphs: The “After Size” show the amount of heap space in use after each garbage collection. Many Java objects are still referenced, i.e. alive, during each garbage collection. This may indicate that the application has a memory leak, or may indicate that the application has a very large memory footprint. Typically, an application's memory footprint plateau's in the early stage of execution. One would expect this graph to have a flat top. The steep decline in the heap space may indicate that the application crashed after 2:00. The second graph shows that the outliers in real execution time, discussed above, occur near 2:00. when the Java heap seems to be quite full. The third graph shows that Full GCs are infrequent during the first few hours of execution. The rate of Full GC's, (the slope of the cummulative Full GC line), changes near midnight.   plot(clipped.g1gc.z[,c("AfterSize","RealTime","FullCount")], xlab="Time of Day", col=c("#1b9e77","red","#1b9e77")) GC Analysis of heap recovered Each GC trace includes the amount of heap space in use before and after the individual GC event. During garbage coolection, unreferenced objects are identified, the space holding the unreferenced objects is freed, and thus, the difference in before and after usage indicates how much space has been freed. The following box plot and bar chart both demonstrate the same point - the amount of heap space freed per garbage colloection is surprisingly low. par(mfrow=c(2,1)) boxplot(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", horizontal = TRUE, col="red") hist(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", breaks=100, col="red") box(which = "outer", lty = "solid") This graph is the most interesting. The dark blue area shows how much heap is occupied by referenced Java objects. This represents memory that holds live data. The red fringe at the top shows how much data was recovered after each garbage collection. barplot(clipped.g1gc.z[,c("AfterSize","Delta")], col=c("#7570b3","#e7298a"), xlab="Time of Day", border=NA) legend("topleft", c("Live Objects","Heap Recovered on GC"), fill=c("#7570b3","#e7298a")) box(which = "outer", lty = "solid") When I discuss the data in the log files with the customer, I will ask for an explaination for the large amount of referenced data resident in the Java heap. There are two are posibilities: There is a memory leak and the amount of space required to hold referenced objects will continue to grow, limited only by the maximum heap size. After the maximum heap size is reached, the JVM will throw an “Out of Memory” exception every time that the application tries to allocate a new object. If this is the case, the aplication needs to be debugged to identify why old objects are referenced when they are no longer needed. The application has a legitimate requirement to keep a large amount of data in memory. The customer may want to further increase the maximum heap size. Another possible solution would be to partition the application across multiple cluster nodes, where each node has responsibility for managing a unique subset of the data. Conclusion In conclusion, R is a very powerful tool for the analysis of Java garbage collection log files. The primary difficulty is data cleansing so that information can be read into an R data frame. Once the data has been read into R, a rich set of tools may be used for thorough evaluation.

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• Is there a Telecommunications Reference Architecture?

  - by raul.goycoolea

  @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Abstract   Reference architecture provides needed architectural information that can be provided in advance to an enterprise to enable consistent architectural best practices. Enterprise Reference Architecture helps business owners to actualize their strategies, vision, objectives, and principles. It evaluates the IT systems, based on Reference Architecture goals, principles, and standards. It helps to reduce IT costs by increasing functionality, availability, scalability, etc. Telecom Reference Architecture provides customers with the flexibility to view bundled service bills online with the provision of multiple services. It provides real-time, flexible billing and charging systems, to handle complex promotions, discounts, and settlements with multiple parties. This paper attempts to describe the Reference Architecture for the Telecom Enterprises. It lays the foundation for a Telecom Reference Architecture by articulating the requirements, drivers, and pitfalls for telecom service providers. It describes generic reference architecture for telecom enterprises and moves on to explain how to achieve Enterprise Reference Architecture by using SOA.   Introduction   A Reference Architecture provides a methodology, set of practices, template, and standards based on a set of successful solutions implemented earlier. These solutions have been generalized and structured for the depiction of both a logical and a physical architecture, based on the harvesting of a set of patterns that describe observations in a number of successful implementations. It helps as a reference for the various architectures that an enterprise can implement to solve various problems. It can be used as the starting point or the point of comparisons for various departments/business entities of a company, or for the various companies for an enterprise. It provides multiple views for multiple stakeholders.   Major artifacts of the Enterprise Reference Architecture are methodologies, standards, metadata, documents, design patterns, etc.   Purpose of Reference Architecture   In most cases, architects spend a lot of time researching, investigating, defining, and re-arguing architectural decisions. It is like reinventing the wheel as their peers in other organizations or even the same organization have already spent a lot of time and effort defining their own architectural practices. This prevents an organization from learning from its own experiences and applying that knowledge for increased effectiveness.   Reference architecture provides missing architectural information that can be provided in advance to project team members to enable consistent architectural best practices.   Enterprise Reference Architecture helps an enterprise to achieve the following at the abstract level:   ·       Reference architecture is more of a communication channel to an enterprise ·       Helps the business owners to accommodate to their strategies, vision, objectives, and principles. ·       Evaluates the IT systems based on Reference Architecture Principles ·       Reduces IT spending through increasing functionality, availability, scalability, etc ·       A Real-time Integration Model helps to reduce the latency of the data updates Is used to define a single source of Information ·       Provides a clear view on how to manage information and security ·       Defines the policy around the data ownership, product boundaries, etc. ·       Helps with cost optimization across project and solution portfolios by eliminating unused or duplicate investments and assets ·       Has a shorter implementation time and cost   Once the reference architecture is in place, the set of architectural principles, standards, reference models, and best practices ensure that the aligned investments have the greatest possible likelihood of success in both the near term and the long term (TCO).     Common pitfalls for Telecom Service Providers   Telecom Reference Architecture serves as the first step towards maturity for a telecom service provider. During the course of our assignments/experiences with telecom players, we have come across the following observations – Some of these indicate a lack of maturity of the telecom service provider:   ·       In markets that are growing and not so mature, it has been observed that telcos have a significant amount of in-house or home-grown applications. In some of these markets, the growth has been so rapid that IT has been unable to cope with business demands. Telcos have shown a tendency to come up with workarounds in their IT applications so as to meet business needs. ·       Even for core functions like provisioning or mediation, some telcos have tried to manage with home-grown applications. ·       Most of the applications do not have the required scalability or maintainability to sustain growth in volumes or functionality. ·       Applications face interoperability issues with other applications in the operator's landscape. Integrating a new application or network element requires considerable effort on the part of the other applications. ·       Application boundaries are not clear, and functionality that is not in the initial scope of that application gets pushed onto it. This results in the development of the multiple, small applications without proper boundaries. ·       Usage of Legacy OSS/BSS systems, poor Integration across Multiple COTS Products and Internal Systems. Most of the Integrations are developed on ad-hoc basis and Point-to-Point Integration. ·       Redundancy of the business functions in different applications • Fragmented data across the different applications and no integrated view of the strategic data • Lot of performance Issues due to the usage of the complex integration across OSS and BSS systems   However, this is where the maturity of the telecom industry as a whole can be of help. The collaborative efforts of telcos to overcome some of these problems have resulted in bodies like the TM Forum. They have come up with frameworks for business processes, data, applications, and technology for telecom service providers. These could be a good starting point for telcos to clean up their enterprise landscape.   Industry Trends in Telecom Reference Architecture   Telecom reference architectures are evolving rapidly because telcos are facing business and IT challenges.   “The reality is that there probably is no killer application, no silver bullet that the telcos can latch onto to carry them into a 21st Century.... Instead, there are probably hundreds – perhaps thousands – of niche applications.... And the only way to find which of these works for you is to try out lots of them, ramp up the ones that work, and discontinue the ones that fail.” – Martin Creaner President & CTO TM Forum.   The following trends have been observed in telecom reference architecture:   ·       Transformation of business structures to align with customer requirements ·       Adoption of more Internet-like technical architectures. The Web 2.0 concept is increasingly being used. ·       Virtualization of the traditional operations support system (OSS) ·       Adoption of SOA to support development of IP-based services ·       Adoption of frameworks like Service Delivery Platforms (SDPs) and IP Multimedia Subsystem ·       (IMS) to enable seamless deployment of various services over fixed and mobile networks ·       Replacement of in-house, customized, and stove-piped OSS/BSS with standards-based COTS products ·       Compliance with industry standards and frameworks like eTOM, SID, and TAM to enable seamless integration with other standards-based products   Drivers of Reference Architecture   The drivers of the Reference Architecture are Reference Architecture Goals, Principles, and Enterprise Vision and Telecom Transformation. The details are depicted below diagram. @font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }div.Section1 { page: Section1; } Figure 1. Drivers for Reference Architecture @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Today’s telecom reference architectures should seamlessly integrate traditional legacy-based applications and transition to next-generation network technologies (e.g., IP multimedia subsystems). This has resulted in new requirements for flexible, real-time billing and OSS/BSS systems and implications on the service provider’s organizational requirements and structure.   Telecom reference architectures are today expected to:   ·       Integrate voice, messaging, email and other VAS over fixed and mobile networks, back end systems ·       Be able to provision multiple services and service bundles • Deliver converged voice, video and data services ·       Leverage the existing Network Infrastructure ·       Provide real-time, flexible billing and charging systems to handle complex promotions, discounts, and settlements with multiple parties. ·       Support charging of advanced data services such as VoIP, On-Demand, Services (e.g.  Video), IMS/SIP Services, Mobile Money, Content Services and IPTV. ·       Help in faster deployment of new services • Serve as an effective platform for collaboration between network IT and business organizations ·       Harness the potential of converging technology, networks, devices and content to develop multimedia services and solutions of ever-increasing sophistication on a single Internet Protocol (IP) ·       Ensure better service delivery and zero revenue leakage through real-time balance and credit management ·       Lower operating costs to drive profitability   Enterprise Reference Architecture   The Enterprise Reference Architecture (RA) fills the gap between the concepts and vocabulary defined by the reference model and the implementation. Reference architecture provides detailed architectural information in a common format such that solutions can be repeatedly designed and deployed in a consistent, high-quality, supportable fashion. This paper attempts to describe the Reference Architecture for the Telecom Application Usage and how to achieve the Enterprise Level Reference Architecture using SOA.   • Telecom Reference Architecture • Enterprise SOA based Reference Architecture   Telecom Reference Architecture   Tele Management Forum’s New Generation Operations Systems and Software (NGOSS) is an architectural framework for organizing, integrating, and implementing telecom systems. NGOSS is a component-based framework consisting of the following elements:   ·       The enhanced Telecom Operations Map (eTOM) is a business process framework. ·       The Shared Information Data (SID) model provides a comprehensive information framework that may be specialized for the needs of a particular organization. ·       The Telecom Application Map (TAM) is an application framework to depict the functional footprint of applications, relative to the horizontal processes within eTOM. ·       The Technology Neutral Architecture (TNA) is an integrated framework. TNA is an architecture that is sustainable through technology changes.   NGOSS Architecture Standards are:   ·       Centralized data ·       Loosely coupled distributed systems ·       Application components/re-use  ·       A technology-neutral system framework with technology specific implementations ·       Interoperability to service provider data/processes ·       Allows more re-use of business components across multiple business scenarios ·       Workflow automation   The traditional operator systems architecture consists of four layers,   ·       Business Support System (BSS) layer, with focus toward customers and business partners. Manages order, subscriber, pricing, rating, and billing information. ·       Operations Support System (OSS) layer, built around product, service, and resource inventories. ·       Networks layer – consists of Network elements and 3rd Party Systems. ·       Integration Layer – to maximize application communication and overall solution flexibility.   Reference architecture for telecom enterprises is depicted below. @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Figure 2. Telecom Reference Architecture   The major building blocks of any Telecom Service Provider architecture are as follows:   1. Customer Relationship Management   CRM encompasses the end-to-end lifecycle of the customer: customer initiation/acquisition, sales, ordering, and service activation, customer care and support, proactive campaigns, cross sell/up sell, and retention/loyalty.   CRM also includes the collection of customer information and its application to personalize, customize, and integrate delivery of service to a customer, as well as to identify opportunities for increasing the value of the customer to the enterprise.   The key functionalities related to Customer Relationship Management are   ·       Manage the end-to-end lifecycle of a customer request for products. ·       Create and manage customer profiles. ·       Manage all interactions with customers – inquiries, requests, and responses. ·       Provide updates to Billing and other south bound systems on customer/account related updates such as customer/ account creation, deletion, modification, request bills, final bill, duplicate bills, credit limits through Middleware. ·       Work with Order Management System, Product, and Service Management components within CRM. ·       Manage customer preferences – Involve all the touch points and channels to the customer, including contact center, retail stores, dealers, self service, and field service, as well as via any media (phone, face to face, web, mobile device, chat, email, SMS, mail, the customer's bill, etc.). ·       Support single interface for customer contact details, preferences, account details, offers, customer premise equipment, bill details, bill cycle details, and customer interactions.   CRM applications interact with customers through customer touch points like portals, point-of-sale terminals, interactive voice response systems, etc. The requests by customers are sent via fulfillment/provisioning to billing system for ordering processing.   2. Billing and Revenue Management   Billing and Revenue Management handles the collection of appropriate usage records and production of timely and accurate bills – for providing pre-bill usage information and billing to customers; for processing their payments; and for performing payment collections. In addition, it handles customer inquiries about bills, provides billing inquiry status, and is responsible for resolving billing problems to the customer's satisfaction in a timely manner. This process grouping also supports prepayment for services.   The key functionalities provided by these applications are   ·       To ensure that enterprise revenue is billed and invoices delivered appropriately to customers. ·       To manage customers’ billing accounts, process their payments, perform payment collections, and monitor the status of the account balance. ·       To ensure the timely and effective fulfillment of all customer bill inquiries and complaints. ·       Collect the usage records from mediation and ensure appropriate rating and discounting of all usage and pricing. ·       Support revenue sharing; split charging where usage is guided to an account different from the service consumer. ·       Support prepaid and post-paid rating. ·       Send notification on approach / exceeding the usage thresholds as enforced by the subscribed offer, and / or as setup by the customer. ·       Support prepaid, post paid, and hybrid (where some services are prepaid and the rest of the services post paid) customers and conversion from post paid to prepaid, and vice versa. ·       Support different billing function requirements like charge prorating, promotion, discount, adjustment, waiver, write-off, account receivable, GL Interface, late payment fee, credit control, dunning, account or service suspension, re-activation, expiry, termination, contract violation penalty, etc. ·       Initiate direct debit to collect payment against an invoice outstanding. ·       Send notification to Middleware on different events; for example, payment receipt, pre-suspension, threshold exceed, etc.   Billing systems typically get usage data from mediation systems for rating and billing. They get provisioning requests from order management systems and inquiries from CRM systems. Convergent and real-time billing systems can directly get usage details from network elements.   3. Mediation   Mediation systems transform/translate the Raw or Native Usage Data Records into a general format that is acceptable to billing for their rating purposes.   The following lists the high-level roles and responsibilities executed by the Mediation system in the end-to-end solution.   ·       Collect Usage Data Records from different data sources – like network elements, routers, servers – via different protocol and interfaces. ·       Process Usage Data Records – Mediation will process Usage Data Records as per the source format. ·       Validate Usage Data Records from each source. ·       Segregates Usage Data Records coming from each source to multiple, based on the segregation requirement of end Application. ·       Aggregates Usage Data Records based on the aggregation rule if any from different sources. ·       Consolidates multiple Usage Data Records from each source. ·       Delivers formatted Usage Data Records to different end application like Billing, Interconnect, Fraud Management, etc. ·       Generates audit trail for incoming Usage Data Records and keeps track of all the Usage Data Records at various stages of mediation process. ·       Checks duplicate Usage Data Records across files for a given time window.   4. Fulfillment   This area is responsible for providing customers with their requested products in a timely and correct manner. It translates the customer's business or personal need into a solution that can be delivered using the specific products in the enterprise's portfolio. This process informs the customers of the status of their purchase order, and ensures completion on time, as well as ensuring a delighted customer. These processes are responsible for accepting and issuing orders. They deal with pre-order feasibility determination, credit authorization, order issuance, order status and tracking, customer update on customer order activities, and customer notification on order completion. Order management and provisioning applications fall into this category.   The key functionalities provided by these applications are   ·       Issuing new customer orders, modifying open customer orders, or canceling open customer orders; ·       Verifying whether specific non-standard offerings sought by customers are feasible and supportable; ·       Checking the credit worthiness of customers as part of the customer order process; ·       Testing the completed offering to ensure it is working correctly; ·       Updating of the Customer Inventory Database to reflect that the specific product offering has been allocated, modified, or cancelled; ·       Assigning and tracking customer provisioning activities; ·       Managing customer provisioning jeopardy conditions; and ·       Reporting progress on customer orders and other processes to customer.   These applications typically get orders from CRM systems. They interact with network elements and billing systems for fulfillment of orders.   5. Enterprise Management   This process area includes those processes that manage enterprise-wide activities and needs, or have application within the enterprise as a whole. They encompass all business management processes that   ·       Are necessary to support the whole of the enterprise, including processes for financial management, legal management, regulatory management, process, cost, and quality management, etc.;   ·       Are responsible for setting corporate policies, strategies, and directions, and for providing guidelines and targets for the whole of the business, including strategy development and planning for areas, such as Enterprise Architecture, that are integral to the direction and development of the business;   ·       Occur throughout the enterprise, including processes for project management, performance assessments, cost assessments, etc.     (i) Enterprise Risk Management:   Enterprise Risk Management focuses on assuring that risks and threats to the enterprise value and/or reputation are identified, and appropriate controls are in place to minimize or eliminate the identified risks. The identified risks may be physical or logical/virtual. Successful risk management ensures that the enterprise can support its mission critical operations, processes, applications, and communications in the face of serious incidents such as security threats/violations and fraud attempts. Two key areas covered in Risk Management by telecom operators are:   ·       Revenue Assurance: Revenue assurance system will be responsible for identifying revenue loss scenarios across components/systems, and will help in rectifying the problems. The following lists the high-level roles and responsibilities executed by the Revenue Assurance system in the end-to-end solution. o   Identify all usage information dropped when networks are being upgraded. o   Interconnect bill verification. o   Identify where services are routinely provisioned but never billed. o   Identify poor sales policies that are intensifying collections problems. o   Find leakage where usage is sent to error bucket and never billed for. o   Find leakage where field service, CRM, and network build-out are not optimized.   ·       Fraud Management: Involves collecting data from different systems to identify abnormalities in traffic patterns, usage patterns, and subscription patterns to report suspicious activity that might suggest fraudulent usage of resources, resulting in revenue losses to the operator.   The key roles and responsibilities of the system component are as follows:   o   Fraud management system will capture and monitor high usage (over a certain threshold) in terms of duration, value, and number of calls for each subscriber. The threshold for each subscriber is decided by the system and fixed automatically. o   Fraud management will be able to detect the unauthorized access to services for certain subscribers. These subscribers may have been provided unauthorized services by employees. The component will raise the alert to the operator the very first time of such illegal calls or calls which are not billed. o   The solution will be to have an alarm management system that will deliver alarms to the operator/provider whenever it detects a fraud, thus minimizing fraud by catching it the first time it occurs. o   The Fraud Management system will be capable of interfacing with switches, mediation systems, and billing systems   (ii) Knowledge Management   This process focuses on knowledge management, technology research within the enterprise, and the evaluation of potential technology acquisitions.   Key responsibilities of knowledge base management are to   ·       Maintain knowledge base – Creation and updating of knowledge base on ongoing basis. ·       Search knowledge base – Search of knowledge base on keywords or category browse ·       Maintain metadata – Management of metadata on knowledge base to ensure effective management and search. ·       Run report generator. ·       Provide content – Add content to the knowledge base, e.g., user guides, operational manual, etc.   (iii) Document Management   It focuses on maintaining a repository of all electronic documents or images of paper documents relevant to the enterprise using a system.   (iv) Data Management   It manages data as a valuable resource for any enterprise. For telecom enterprises, the typical areas covered are Master Data Management, Data Warehousing, and Business Intelligence. It is also responsible for data governance, security, quality, and database management.   Key responsibilities of Data Management are   ·       Using ETL, extract the data from CRM, Billing, web content, ERP, campaign management, financial, network operations, asset management info, customer contact data, customer measures, benchmarks, process data, e.g., process inputs, outputs, and measures, into Enterprise Data Warehouse. ·       Management of data traceability with source, data related business rules/decisions, data quality, data cleansing data reconciliation, competitors data – storage for all the enterprise data (customer profiles, products, offers, revenues, etc.) ·       Get online update through night time replication or physical backup process at regular frequency. ·       Provide the data access to business intelligence and other systems for their analysis, report generation, and use.   (v) Business Intelligence   It uses the Enterprise Data to provide the various analysis and reports that contain prospects and analytics for customer retention, acquisition of new customers due to the offers, and SLAs. It will generate right and optimized plans – bolt-ons for the customers.   The following lists the high-level roles and responsibilities executed by the Business Intelligence system at the Enterprise Level:   ·       It will do Pattern analysis and reports problem. ·       It will do Data Analysis – Statistical analysis, data profiling, affinity analysis of data, customer segment wise usage patterns on offers, products, service and revenue generation against services and customer segments. ·       It will do Performance (business, system, and forecast) analysis, churn propensity, response time, and SLAs analysis. ·       It will support for online and offline analysis, and report drill down capability. ·       It will collect, store, and report various SLA data. ·       It will provide the necessary intelligence for marketing and working on campaigns, etc., with cost benefit analysis and predictions.   It will advise on customer promotions with additional services based on loyalty and credit history of customer   ·       It will Interface with Enterprise Data Management system for data to run reports and analysis tasks. It will interface with the campaign schedules, based on historical success evidence.   (vi) Stakeholder and External Relations Management   It manages the enterprise's relationship with stakeholders and outside entities. Stakeholders include shareholders, employee organizations, etc. Outside entities include regulators, local community, and unions. Some of the processes within this grouping are Shareholder Relations, External Affairs, Labor Relations, and Public Relations.   (vii) Enterprise Resource Planning   It is used to manage internal and external resources, including tangible assets, financial resources, materials, and human resources. Its purpose is to facilitate the flow of information between all business functions inside the boundaries of the enterprise and manage the connections to outside stakeholders. ERP systems consolidate all business operations into a uniform and enterprise wide system environment.   The key roles and responsibilities for Enterprise System are given below:   ·        It will handle responsibilities such as core accounting, financial, and management reporting. ·       It will interface with CRM for capturing customer account and details. ·       It will interface with billing to capture the billing revenue and other financial data. ·       It will be responsible for executing the dunning process. Billing will send the required feed to ERP for execution of dunning. ·       It will interface with the CRM and Billing through batch interfaces. Enterprise management systems are like horizontals in the enterprise and typically interact with all major telecom systems. E.g., an ERP system interacts with CRM, Fulfillment, and Billing systems for different kinds of data exchanges.   6. External Interfaces/Touch Points   The typical external parties are customers, suppliers/partners, employees, shareholders, and other stakeholders. External interactions from/to a Service Provider to other parties can be achieved by a variety of mechanisms, including:   ·       Exchange of emails or faxes ·       Call Centers ·       Web Portals ·       Business-to-Business (B2B) automated transactions   These applications provide an Internet technology driven interface to external parties to undertake a variety of business functions directly for themselves. These can provide fully or partially automated service to external parties through various touch points.   Typical characteristics of these touch points are   ·       Pre-integrated self-service system, including stand-alone web framework or integration front end with a portal engine ·       Self services layer exposing atomic web services/APIs for reuse by multiple systems across the architectural environment ·       Portlets driven connectivity exposing data and services interoperability through a portal engine or web application   These touch points mostly interact with the CRM systems for requests, inquiries, and responses.   7. Middleware   The component will be primarily responsible for integrating the different systems components under a common platform. It should provide a Standards-Based Platform for building Service Oriented Architecture and Composite Applications. The following lists the high-level roles and responsibilities executed by the Middleware component in the end-to-end solution.   ·       As an integration framework, covering to and fro interfaces ·       Provide a web service framework with service registry. ·       Support SOA framework with SOA service registry. ·       Each of the interfaces from / to Middleware to other components would handle data transformation, translation, and mapping of data points. ·       Receive data from the caller / activate and/or forward the data to the recipient system in XML format. ·       Use standard XML for data exchange. ·       Provide the response back to the service/call initiator. ·       Provide a tracking until the response completion. ·       Keep a store transitional data against each call/transaction. ·       Interface through Middleware to get any information that is possible and allowed from the existing systems to enterprise systems; e.g., customer profile and customer history, etc. ·       Provide the data in a common unified format to the SOA calls across systems, and follow the Enterprise Architecture directive. ·       Provide an audit trail for all transactions being handled by the component.   8. Network Elements   The term Network Element means a facility or equipment used in the provision of a telecommunications service. Such terms also includes features, functions, and capabilities that are provided by means of such facility or equipment, including subscriber numbers, databases, signaling systems, and information sufficient for billing and collection or used in the transmission, routing, or other provision of a telecommunications service.   Typical network elements in a GSM network are Home Location Register (HLR), Intelligent Network (IN), Mobile Switching Center (MSC), SMS Center (SMSC), and network elements for other value added services like Push-to-talk (PTT), Ring Back Tone (RBT), etc.   Network elements are invoked when subscribers use their telecom devices for any kind of usage. These elements generate usage data and pass it on to downstream systems like mediation and billing system for rating and billing. They also integrate with provisioning systems for order/service fulfillment.   9. 3rd Party Applications   3rd Party systems are applications like content providers, payment gateways, point of sale terminals, and databases/applications maintained by the Government.   Depending on applicability and the type of functionality provided by 3rd party applications, the integration with different telecom systems like CRM, provisioning, and billing will be done.   10. Service Delivery Platform   A service delivery platform (SDP) provides the architecture for the rapid deployment, provisioning, execution, management, and billing of value added telecom services. SDPs are based on the concept of SOA and layered architecture. They support the delivery of voice, data services, and content in network and device-independent fashion. They allow application developers to aggregate network capabilities, services, and sources of content. SDPs typically contain layers for web services exposure, service application development, and network abstraction.   SOA Reference Architecture   SOA concept is based on the principle of developing reusable business service and building applications by composing those services, instead of building monolithic applications in silos. It’s about bridging the gap between business and IT through a set of business-aligned IT services, using a set of design principles, patterns, and techniques.   In an SOA, resources are made available to participants in a value net, enterprise, line of business (typically spanning multiple applications within an enterprise or across multiple enterprises). It consists of a set of business-aligned IT services that collectively fulfill an organization’s business processes and goals. We can choreograph these services into composite applications and invoke them through standard protocols. SOA, apart from agility and reusability, enables:   ·       The business to specify processes as orchestrations of reusable services ·       Technology agnostic business design, with technology hidden behind service interface ·       A contractual-like interaction between business and IT, based on service SLAs ·       Accountability and governance, better aligned to business services ·       Applications interconnections untangling by allowing access only through service interfaces, reducing the daunting side effects of change ·       Reduced pressure to replace legacy and extended lifetime for legacy applications, through encapsulation in services   ·       A Cloud Computing paradigm, using web services technologies, that makes possible service outsourcing on an on-demand, utility-like, pay-per-usage basis   The following section represents the Reference Architecture of logical view for the Telecom Solution. The new custom built application needs to align with this logical architecture in the long run to achieve EA benefits.   Packaged implementation applications, such as ERP billing applications, need to expose their functions as service providers (as other applications consume) and interact with other applications as service consumers.   COT applications need to expose services through wrappers such as adapters to utilize existing resources and at the same time achieve Enterprise Architecture goal and objectives.   The following are the various layers for Enterprise level deployment of SOA. This diagram captures the abstract view of Enterprise SOA layers and important components of each layer. Layered architecture means decomposition of services such that most interactions occur between adjacent layers. However, there is no strict rule that top layers should not directly communicate with bottom layers.   The diagram below represents the important logical pieces that would result from overall SOA transformation. @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Figure 3. Enterprise SOA Reference Architecture 1.          Operational System Layer: This layer consists of all packaged applications like CRM, ERP, custom built applications, COTS based applications like Billing, Revenue Management, Fulfilment, and the Enterprise databases that are essential and contribute directly or indirectly to the Enterprise OSS/BSS Transformation.   ERP holds the data of Asset Lifecycle Management, Supply Chain, and Advanced Procurement and Human Capital Management, etc.   CRM holds the data related to Order, Sales, and Marketing, Customer Care, Partner Relationship Management, Loyalty, etc.   Content Management handles Enterprise Search and Query. Billing application consists of the following components:   ·       Collections Management, Customer Billing Management, Invoices, Real-Time Rating, Discounting, and Applying of Charges ·       Enterprise databases will hold both the application and service data, whether structured or unstructured.   MDM - Master data majorly consists of Customer, Order, Product, and Service Data.     2.          Enterprise Component Layer:   This layer consists of the Application Services and Common Services that are responsible for realizing the functionality and maintaining the QoS of the exposed services. This layer uses container-based technologies such as application servers to implement the components, workload management, high availability, and load balancing.   Application Services: This Service Layer enables application, technology, and database abstraction so that the complex accessing logic is hidden from the other service layers. This is a basic service layer, which exposes application functionalities and data as reusable services. The three types of the Application access services are:   ·       Application Access Service: This Service Layer exposes application level functionalities as a reusable service between BSS to BSS and BSS to OSS integration. This layer is enabled using disparate technology such as Web Service, Integration Servers, and Adaptors, etc.   ·       Data Access Service: This Service Layer exposes application data services as a reusable reference data service. This is done via direct interaction with application data. and provides the federated query.   ·       Network Access Service: This Service Layer exposes provisioning layer as a reusable service from OSS to OSS integration. This integration service emphasizes the need for high performance, stateless process flows, and distributed design.   Common Services encompasses management of structured, semi-structured, and unstructured data such as information services, portal services, interaction services, infrastructure services, and security services, etc.   3.          Integration Layer:   This consists of service infrastructure components like service bus, service gateway for partner integration, service registry, service repository, and BPEL processor. Service bus will carry the service invocation payloads/messages between consumers and providers. The other important functions expected from it are itinerary based routing, distributed caching of routing information, transformations, and all qualities of service for messaging-like reliability, scalability, and availability, etc. Service registry will hold all contracts (wsdl) of services, and it helps developers to locate or discover service during design time or runtime.   • BPEL processor would be useful in orchestrating the services to compose a complex business scenario or process. • Workflow and business rules management are also required to support manual triggering of certain activities within business process. based on the rules setup and also the state machine information. Application, data, and service mediation layer typically forms the overall composite application development framework or SOA Framework.   4.          Business Process Layer: These are typically the intermediate services layer and represent Shared Business Process Services. At Enterprise Level, these services are from Customer Management, Order Management, Billing, Finance, and Asset Management application domains.   5.          Access Layer: This layer consists of portals for Enterprise and provides a single view of Enterprise information management and dashboard services.   6.          Channel Layer: This consists of various devices; applications that form part of extended enterprise; browsers through which users access the applications.   7.          Client Layer: This designates the different types of users accessing the enterprise applications. The type of user typically would be an important factor in determining the level of access to applications.   8.          Vertical pieces like management, monitoring, security, and development cut across all horizontal layers Management and monitoring involves all aspects of SOA-like services, SLAs, and other QoS lifecycle processes for both applications and services surrounding SOA governance.     9.          EA Governance, Reference Architecture, Roadmap, Principles, and Best Practices:   EA Governance is important in terms of providing the overall direction to SOA implementation within the enterprise. This involves board-level involvement, in addition to business and IT executives. At a high level, this involves managing the SOA projects implementation, managing SOA infrastructure, and controlling the entire effort through all fine-tuned IT processes in accordance with COBIT (Control Objectives for Information Technology).   Devising tools and techniques to promote reuse culture, and the SOA way of doing things needs competency centers to be established in addition to training the workforce to take up new roles that are suited to SOA journey.   Conclusions   Reference Architectures can serve as the basis for disparate architecture efforts throughout the organization, even if they use different tools and technologies. Reference architectures provide best practices and approaches in the independent way a vendor deals with technology and standards. Reference Architectures model the abstract architectural elements for an enterprise independent of the technologies, protocols, and products that are used to implement an SOA. Telecom enterprises today are facing significant business and technology challenges due to growing competition, a multitude of services, and convergence. Adopting architectural best practices could go a long way in meeting these challenges. The use of SOA-based architecture for communication to each of the external systems like Billing, CRM, etc., in OSS/BSS system has made the architecture very loosely coupled, with greater flexibility. Any change in the external systems would be absorbed at the Integration Layer without affecting the rest of the ecosystem. The use of a Business Process Management (BPM) tool makes the management and maintenance of the business processes easy, with better performance in terms of lead time, quality, and cost. Since the Architecture is based on standards, it will lower the cost of deploying and managing OSS/BSS applications over their lifecycles.

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• Agile Development

  - by James Oloo Onyango

  Alot of literature has and is being written about agile developement and its surrounding philosophies. In my quest to find the best way to express the importance of agile methodologies, i have found Robert C. Martin's "A Satire Of Two Companies" to be both the most concise and thorough! Enjoy the read! Rufus Inc Project Kick Off Your name is Bob. The date is January 3, 2001, and your head still aches from the recent millennial revelry. You are sitting in a conference room with several managers and a group of your peers. You are a project team leader. Your boss is there, and he has brought along all of his team leaders. His boss called the meeting. "We have a new project to develop," says your boss's boss. Call him BB. The points in his hair are so long that they scrape the ceiling. Your boss's points are just starting to grow, but he eagerly awaits the day when he can leave Brylcream stains on the acoustic tiles. BB describes the essence of the new market they have identified and the product they want to develop to exploit this market. "We must have this new project up and working by fourth quarter October 1," BB demands. "Nothing is of higher priority, so we are cancelling your current project." The reaction in the room is stunned silence. Months of work are simply going to be thrown away. Slowly, a murmur of objection begins to circulate around the conference table.   His points give off an evil green glow as BB meets the eyes of everyone in the room. One by one, that insidious stare reduces each attendee to quivering lumps of protoplasm. It is clear that he will brook no discussion on this matter. Once silence has been restored, BB says, "We need to begin immediately. How long will it take you to do the analysis?" You raise your hand. Your boss tries to stop you, but his spitwad misses you and you are unaware of his efforts.   "Sir, we can't tell you how long the analysis will take until we have some requirements." "The requirements document won't be ready for 3 or 4 weeks," BB says, his points vibrating with frustration. "So, pretend that you have the requirements in front of you now. How long will you require for analysis?" No one breathes. Everyone looks around to see whether anyone has some idea. "If analysis goes beyond April 1, we have a problem. Can you finish the analysis by then?" Your boss visibly gathers his courage: "We'll find a way, sir!" His points grow 3 mm, and your headache increases by two Tylenol. "Good." BB smiles. "Now, how long will it take to do the design?" "Sir," you say. Your boss visibly pales. He is clearly worried that his 3 mms are at risk. "Without an analysis, it will not be possible to tell you how long design will take." BB's expression shifts beyond austere.   "PRETEND you have the analysis already!" he says, while fixing you with his vacant, beady little eyes. "How long will it take you to do the design?" Two Tylenol are not going to cut it. Your boss, in a desperate attempt to save his new growth, babbles: "Well, sir, with only six months left to complete the project, design had better take no longer than 3 months."   "I'm glad you agree, Smithers!" BB says, beaming. Your boss relaxes. He knows his points are secure. After a while, he starts lightly humming the Brylcream jingle. BB continues, "So, analysis will be complete by April 1, design will be complete by July 1, and that gives you 3 months to implement the project. This meeting is an example of how well our new consensus and empowerment policies are working. Now, get out there and start working. I'll expect to see TQM plans and QIT assignments on my desk by next week. Oh, and don't forget that your crossfunctional team meetings and reports will be needed for next month's quality audit." "Forget the Tylenol," you think to yourself as you return to your cubicle. "I need bourbon."   Visibly excited, your boss comes over to you and says, "Gosh, what a great meeting. I think we're really going to do some world shaking with this project." You nod in agreement, too disgusted to do anything else. "Oh," your boss continues, "I almost forgot." He hands you a 30-page document. "Remember that the SEI is coming to do an evaluation next week. This is the evaluation guide. You need to read through it, memorize it, and then shred it. It tells you how to answer any questions that the SEI auditors ask you. It also tells you what parts of the building you are allowed to take them to and what parts to avoid. We are determined to be a CMM level 3 organization by June!"   You and your peers start working on the analysis of the new project. This is difficult because you have no requirements. But from the 10-minute introduction given by BB on that fateful morning, you have some idea of what the product is supposed to do.   Corporate process demands that you begin by creating a use case document. You and your team begin enumerating use cases and drawing oval and stick diagrams. Philosophical debates break out among the team members. There is disagreement as to whether certain use cases should be connected with <<extends>> or <<includes>> relationships. Competing models are created, but nobody knows how to evaluate them. The debate continues, effectively paralyzing progress.   After a week, somebody finds the iceberg.com Web site, which recommends disposing entirely of <<extends>> and <<includes>> and replacing them with <<precedes>> and <<uses>>. The documents on this Web site, authored by Don Sengroiux, describes a method known as stalwart-analysis, which claims to be a step-by-step method for translating use cases into design diagrams. More competing use case models are created using this new scheme, but again, people can't agree on how to evaluate them. The thrashing continues. More and more, the use case meetings are driven by emotion rather than by reason. If it weren't for the fact that you don't have requirements, you'd be pretty upset by the lack of progress you are making. The requirements document arrives on February 15. And then again on February 20, 25, and every week thereafter. Each new version contradicts the previous one. Clearly, the marketing folks who are writing the requirements, empowered though they might be, are not finding consensus.   At the same time, several new competing use case templates have been proposed by the various team members. Each template presents its own particularly creative way of delaying progress. The debates rage on. On March 1, Prudence Putrigence, the process proctor, succeeds in integrating all the competing use case forms and templates into a single, all-encompassing form. Just the blank form is 15 pages long. She has managed to include every field that appeared on all the competing templates. She also presents a 159- page document describing how to fill out the use case form. All current use cases must be rewritten according to the new standard.   You marvel to yourself that it now requires 15 pages of fill-in-the-blank and essay questions to answer the question: What should the system do when the user presses Return? The corporate process (authored by L. E. Ott, famed author of "Holistic Analysis: A Progressive Dialectic for Software Engineers") insists that you discover all primary use cases, 87 percent of all secondary use cases, and 36.274 percent of all tertiary use cases before you can complete analysis and enter the design phase. You have no idea what a tertiary use case is. So in an attempt to meet this requirement, you try to get your use case document reviewed by the marketing department, which you hope will know what a tertiary use case is.   Unfortunately, the marketing folks are too busy with sales support to talk to you. Indeed, since the project started, you have not been able to get a single meeting with marketing, which has provided a never-ending stream of changing and contradictory requirements documents.   While one team has been spinning endlessly on the use case document, another team has been working out the domain model. Endless variations of UML documents are pouring out of this team. Every week, the model is reworked.   The team members can't decide whether to use <<interfaces>> or <<types>> in the model. A huge disagreement has been raging on the proper syntax and application of OCL. Others on the team just got back from a 5-day class on catabolism, and have been producing incredibly detailed and arcane diagrams that nobody else can fathom.   On March 27, with one week to go before analysis is to be complete, you have produced a sea of documents and diagrams but are no closer to a cogent analysis of the problem than you were on January 3. **** And then, a miracle happens.   **** On Saturday, April 1, you check your e-mail from home. You see a memo from your boss to BB. It states unequivocally that you are done with the analysis! You phone your boss and complain. "How could you have told BB that we were done with the analysis?" "Have you looked at a calendar lately?" he responds. "It's April 1!" The irony of that date does not escape you. "But we have so much more to think about. So much more to analyze! We haven't even decided whether to use <<extends>> or <<precedes>>!" "Where is your evidence that you are not done?" inquires your boss, impatiently. "Whaaa . . . ." But he cuts you off. "Analysis can go on forever; it has to be stopped at some point. And since this is the date it was scheduled to stop, it has been stopped. Now, on Monday, I want you to gather up all existing analysis materials and put them into a public folder. Release that folder to Prudence so that she can log it in the CM system by Monday afternoon. Then get busy and start designing."   As you hang up the phone, you begin to consider the benefits of keeping a bottle of bourbon in your bottom desk drawer. They threw a party to celebrate the on-time completion of the analysis phase. BB gave a colon-stirring speech on empowerment. And your boss, another 3 mm taller, congratulated his team on the incredible show of unity and teamwork. Finally, the CIO takes the stage to tell everyone that the SEI audit went very well and to thank everyone for studying and shredding the evaluation guides that were passed out. Level 3 now seems assured and will be awarded by June. (Scuttlebutt has it that managers at the level of BB and above are to receive significant bonuses once the SEI awards level 3.)   As the weeks flow by, you and your team work on the design of the system. Of course, you find that the analysis that the design is supposedly based on is flawedno, useless; no, worse than useless. But when you tell your boss that you need to go back and work some more on the analysis to shore up its weaker sections, he simply states, "The analysis phase is over. The only allowable activity is design. Now get back to it."   So, you and your team hack the design as best you can, unsure of whether the requirements have been properly analyzed. Of course, it really doesn't matter much, since the requirements document is still thrashing with weekly revisions, and the marketing department still refuses to meet with you.     The design is a nightmare. Your boss recently misread a book named The Finish Line in which the author, Mark DeThomaso, blithely suggested that design documents should be taken down to code-level detail. "If we are going to be working at that level of detail," you ask, "why don't we simply write the code instead?" "Because then you wouldn't be designing, of course. And the only allowable activity in the design phase is design!" "Besides," he continues, "we have just purchased a companywide license for Dandelion! This tool enables 'Round the Horn Engineering!' You are to transfer all design diagrams into this tool. It will automatically generate our code for us! It will also keep the design diagrams in sync with the code!" Your boss hands you a brightly colored shrinkwrapped box containing the Dandelion distribution. You accept it numbly and shuffle off to your cubicle. Twelve hours, eight crashes, one disk reformatting, and eight shots of 151 later, you finally have the tool installed on your server. You consider the week your team will lose while attending Dandelion training. Then you smile and think, "Any week I'm not here is a good week." Design diagram after design diagram is created by your team. Dandelion makes it very difficult to draw these diagrams. There are dozens and dozens of deeply nested dialog boxes with funny text fields and check boxes that must all be filled in correctly. And then there's the problem of moving classes between packages. At first, these diagram are driven from the use cases. But the requirements are changing so often that the use cases rapidly become meaningless. Debates rage about whether VISITOR or DECORATOR design patterns should be used. One developer refuses to use VISITOR in any form, claiming that it's not a properly object-oriented construct. Someone refuses to use multiple inheritance, since it is the spawn of the devil. Review meetings rapidly degenerate into debates about the meaning of object orientation, the definition of analysis versus design, or when to use aggregation versus association. Midway through the design cycle, the marketing folks announce that they have rethought the focus of the system. Their new requirements document is completely restructured. They have eliminated several major feature areas and replaced them with feature areas that they anticipate customer surveys will show to be more appropriate. You tell your boss that these changes mean that you need to reanalyze and redesign much of the system. But he says, "The analysis phase is system. But he says, "The analysis phase is over. The only allowable activity is design. Now get back to it."   You suggest that it might be better to create a simple prototype to show to the marketing folks and even some potential customers. But your boss says, "The analysis phase is over. The only allowable activity is design. Now get back to it." Hack, hack, hack, hack. You try to create some kind of a design document that might reflect the new requirements documents. However, the revolution of the requirements has not caused them to stop thrashing. Indeed, if anything, the wild oscillations of the requirements document have only increased in frequency and amplitude.   You slog your way through them.   On June 15, the Dandelion database gets corrupted. Apparently, the corruption has been progressive. Small errors in the DB accumulated over the months into bigger and bigger errors. Eventually, the CASE tool just stopped working. Of course, the slowly encroaching corruption is present on all the backups. Calls to the Dandelion technical support line go unanswered for several days. Finally, you receive a brief e-mail from Dandelion, informing you that this is a known problem and that the solution is to purchase the new version, which they promise will be ready some time next quarter, and then reenter all the diagrams by hand.   ****   Then, on July 1 another miracle happens! You are done with the design!   Rather than go to your boss and complain, you stock your middle desk drawer with some vodka.   **** They threw a party to celebrate the on-time completion of the design phase and their graduation to CMM level 3. This time, you find BB's speech so stirring that you have to use the restroom before it begins. New banners and plaques are all over your workplace. They show pictures of eagles and mountain climbers, and they talk about teamwork and empowerment. They read better after a few scotches. That reminds you that you need to clear out your file cabinet to make room for the brandy. You and your team begin to code. But you rapidly discover that the design is lacking in some significant areas. Actually, it's lacking any significance at all. You convene a design session in one of the conference rooms to try to work through some of the nastier problems. But your boss catches you at it and disbands the meeting, saying, "The design phase is over. The only allowable activity is coding. Now get back to it."   ****   The code generated by Dandelion is really hideous. It turns out that you and your team were using association and aggregation the wrong way, after all. All the generated code has to be edited to correct these flaws. Editing this code is extremely difficult because it has been instrumented with ugly comment blocks that have special syntax that Dandelion needs in order to keep the diagrams in sync with the code. If you accidentally alter one of these comments, the diagrams will be regenerated incorrectly. It turns out that "Round the Horn Engineering" requires an awful lot of effort. The more you try to keep the code compatible with Dandelion, the more errors Dandelion generates. In the end, you give up and decide to keep the diagrams up to date manually. A second later, you decide that there's no point in keeping the diagrams up to date at all. Besides, who has time?   Your boss hires a consultant to build tools to count the number of lines of code that are being produced. He puts a big thermometer graph on the wall with the number 1,000,000 on the top. Every day, he extends the red line to show how many lines have been added. Three days after the thermometer appears on the wall, your boss stops you in the hall. "That graph isn't growing quickly enough. We need to have a million lines done by October 1." "We aren't even sh-sh-sure that the proshect will require a m-million linezh," you blather. "We have to have a million lines done by October 1," your boss reiterates. His points have grown again, and the Grecian formula he uses on them creates an aura of authority and competence. "Are you sure your comment blocks are big enough?" Then, in a flash of managerial insight, he says, "I have it! I want you to institute a new policy among the engineers. No line of code is to be longer than 20 characters. Any such line must be split into two or more preferably more. All existing code needs to be reworked to this standard. That'll get our line count up!"   You decide not to tell him that this will require two unscheduled work months. You decide not to tell him anything at all. You decide that intravenous injections of pure ethanol are the only solution. You make the appropriate arrangements. Hack, hack, hack, and hack. You and your team madly code away. By August 1, your boss, frowning at the thermometer on the wall, institutes a mandatory 50-hour workweek.   Hack, hack, hack, and hack. By September 1st, the thermometer is at 1.2 million lines and your boss asks you to write a report describing why you exceeded the coding budget by 20 percent. He institutes mandatory Saturdays and demands that the project be brought back down to a million lines. You start a campaign of remerging lines. Hack, hack, hack, and hack. Tempers are flaring; people are quitting; QA is raining trouble reports down on you. Customers are demanding installation and user manuals; salespeople are demanding advance demonstrations for special customers; the requirements document is still thrashing, the marketing folks are complaining that the product isn't anything like they specified, and the liquor store won't accept your credit card anymore. Something has to give.    On September 15, BB calls a meeting. As he enters the room, his points are emitting clouds of steam. When he speaks, the bass overtones of his carefully manicured voice cause the pit of your stomach to roll over. "The QA manager has told me that this project has less than 50 percent of the required features implemented. He has also informed me that the system crashes all the time, yields wrong results, and is hideously slow. He has also complained that he cannot keep up with the continuous train of daily releases, each more buggy than the last!" He stops for a few seconds, visibly trying to compose himself. "The QA manager estimates that, at this rate of development, we won't be able to ship the product until December!" Actually, you think it's more like March, but you don't say anything. "December!" BB roars with such derision that people duck their heads as though he were pointing an assault rifle at them. "December is absolutely out of the question. Team leaders, I want new estimates on my desk in the morning. I am hereby mandating 65-hour work weeks until this project is complete. And it better be complete by November 1."   As he leaves the conference room, he is heard to mutter: "Empowermentbah!" * * * Your boss is bald; his points are mounted on BB's wall. The fluorescent lights reflecting off his pate momentarily dazzle you. "Do you have anything to drink?" he asks. Having just finished your last bottle of Boone's Farm, you pull a bottle of Thunderbird from your bookshelf and pour it into his coffee mug. "What's it going to take to get this project done? " he asks. "We need to freeze the requirements, analyze them, design them, and then implement them," you say callously. "By November 1?" your boss exclaims incredulously. "No way! Just get back to coding the damned thing." He storms out, scratching his vacant head.   A few days later, you find that your boss has been transferred to the corporate research division. Turnover has skyrocketed. Customers, informed at the last minute that their orders cannot be fulfilled on time, have begun to cancel their orders. Marketing is re-evaluating whether this product aligns with the overall goals of the company. Memos fly, heads roll, policies change, and things are, overall, pretty grim. Finally, by March, after far too many sixty-five hour weeks, a very shaky version of the software is ready. In the field, bug-discovery rates are high, and the technical support staff are at their wits' end, trying to cope with the complaints and demands of the irate customers. Nobody is happy.   In April, BB decides to buy his way out of the problem by licensing a product produced by Rupert Industries and redistributing it. The customers are mollified, the marketing folks are smug, and you are laid off.     Rupert Industries: Project Alpha   Your name is Robert. The date is January 3, 2001. The quiet hours spent with your family this holiday have left you refreshed and ready for work. You are sitting in a conference room with your team of professionals. The manager of the division called the meeting. "We have some ideas for a new project," says the division manager. Call him Russ. He is a high-strung British chap with more energy than a fusion reactor. He is ambitious and driven but understands the value of a team. Russ describes the essence of the new market opportunity the company has identified and introduces you to Jane, the marketing manager, who is responsible for defining the products that will address it. Addressing you, Jane says, "We'd like to start defining our first product offering as soon as possible. When can you and your team meet with me?" You reply, "We'll be done with the current iteration of our project this Friday. We can spare a few hours for you between now and then. After that, we'll take a few people from the team and dedicate them to you. We'll begin hiring their replacements and the new people for your team immediately." "Great," says Russ, "but I want you to understand that it is critical that we have something to exhibit at the trade show coming up this July. If we can't be there with something significant, we'll lose the opportunity."   "I understand," you reply. "I don't yet know what it is that you have in mind, but I'm sure we can have something by July. I just can't tell you what that something will be right now. In any case, you and Jane are going to have complete control over what we developers do, so you can rest assured that by July, you'll have the most important things that can be accomplished in that time ready to exhibit."   Russ nods in satisfaction. He knows how this works. Your team has always kept him advised and allowed him to steer their development. He has the utmost confidence that your team will work on the most important things first and will produce a high-quality product.   * * *   "So, Robert," says Jane at their first meeting, "How does your team feel about being split up?" "We'll miss working with each other," you answer, "but some of us were getting pretty tired of that last project and are looking forward to a change. So, what are you people cooking up?" Jane beams. "You know how much trouble our customers currently have . . ." And she spends a half hour or so describing the problem and possible solution. "OK, wait a second" you respond. "I need to be clear about this." And so you and Jane talk about how this system might work. Some of her ideas aren't fully formed. You suggest possible solutions. She likes some of them. You continue discussing.   During the discussion, as each new topic is addressed, Jane writes user story cards. Each card represents something that the new system has to do. The cards accumulate on the table and are spread out in front of you. Both you and Jane point at them, pick them up, and make notes on them as you discuss the stories. The cards are powerful mnemonic devices that you can use to represent complex ideas that are barely formed.   At the end of the meeting, you say, "OK, I've got a general idea of what you want. I'm going to talk to the team about it. I imagine they'll want to run some experiments with various database structures and presentation formats. Next time we meet, it'll be as a group, and we'll start identifying the most important features of the system."   A week later, your nascent team meets with Jane. They spread the existing user story cards out on the table and begin to get into some of the details of the system. The meeting is very dynamic. Jane presents the stories in the order of their importance. There is much discussion about each one. The developers are concerned about keeping the stories small enough to estimate and test. So they continually ask Jane to split one story into several smaller stories. Jane is concerned that each story have a clear business value and priority, so as she splits them, she makes sure that this stays true.   The stories accumulate on the table. Jane writes them, but the developers make notes on them as needed. Nobody tries to capture everything that is said; the cards are not meant to capture everything but are simply reminders of the conversation.   As the developers become more comfortable with the stories, they begin writing estimates on them. These estimates are crude and budgetary, but they give Jane an idea of what the story will cost.   At the end of the meeting, it is clear that many more stories could be discussed. It is also clear that the most important stories have been addressed and that they represent several months worth of work. Jane closes the meeting by taking the cards with her and promising to have a proposal for the first release in the morning.   * * *   The next morning, you reconvene the meeting. Jane chooses five cards and places them on the table. "According to your estimates, these cards represent about one perfect team-week's worth of work. The last iteration of the previous project managed to get one perfect team-week done in 3 real weeks. If we can get these five stories done in 3 weeks, we'll be able to demonstrate them to Russ. That will make him feel very comfortable about our progress." Jane is pushing it. The sheepish look on her face lets you know that she knows it too. You reply, "Jane, this is a new team, working on a new project. It's a bit presumptuous to expect that our velocity will be the same as the previous team's. However, I met with the team yesterday afternoon, and we all agreed that our initial velocity should, in fact, be set to one perfectweek for every 3 real-weeks. So you've lucked out on this one." "Just remember," you continue, "that the story estimates and the story velocity are very tentative at this point. We'll learn more when we plan the iteration and even more when we implement it."   Jane looks over her glasses at you as if to say "Who's the boss around here, anyway?" and then smiles and says, "Yeah, don't worry. I know the drill by now."Jane then puts 15 more cards on the table. She says, "If we can get all these cards done by the end of March, we can turn the system over to our beta test customers. And we'll get good feedback from them."   You reply, "OK, so we've got our first iteration defined, and we have the stories for the next three iterations after that. These four iterations will make our first release."   "So," says Jane, can you really do these five stories in the next 3 weeks?" "I don't know for sure, Jane," you reply. "Let's break them down into tasks and see what we get."   So Jane, you, and your team spend the next several hours taking each of the five stories that Jane chose for the first iteration and breaking them down into small tasks. The developers quickly realize that some of the tasks can be shared between stories and that other tasks have commonalities that can probably be taken advantage of. It is clear that potential designs are popping into the developers' heads. From time to time, they form little discussion knots and scribble UML diagrams on some cards.   Soon, the whiteboard is filled with the tasks that, once completed, will implement the five stories for this iteration. You start the sign-up process by saying, "OK, let's sign up for these tasks." "I'll take the initial database generation." Says Pete. "That's what I did on the last project, and this doesn't look very different. I estimate it at two of my perfect workdays." "OK, well, then, I'll take the login screen," says Joe. "Aw, darn," says Elaine, the junior member of the team, "I've never done a GUI, and kinda wanted to try that one."   "Ah, the impatience of youth," Joe says sagely, with a wink in your direction. "You can assist me with it, young Jedi." To Jane: "I think it'll take me about three of my perfect workdays."   One by one, the developers sign up for tasks and estimate them in terms of their own perfect workdays. Both you and Jane know that it is best to let the developers volunteer for tasks than to assign the tasks to them. You also know full well that you daren't challenge any of the developers' estimates. You know these people, and you trust them. You know that they are going to do the very best they can.   The developers know that they can't sign up for more perfect workdays than they finished in the last iteration they worked on. Once each developer has filled his or her schedule for the iteration, they stop signing up for tasks.   Eventually, all the developers have stopped signing up for tasks. But, of course, tasks are still left on the board.   "I was worried that that might happen," you say, "OK, there's only one thing to do, Jane. We've got too much to do in this iteration. What stories or tasks can we remove?" Jane sighs. She knows that this is the only option. Working overtime at the beginning of a project is insane, and projects where she's tried it have not fared well.   So Jane starts to remove the least-important functionality. "Well, we really don't need the login screen just yet. We can simply start the system in the logged-in state." "Rats!" cries Elaine. "I really wanted to do that." "Patience, grasshopper." says Joe. "Those who wait for the bees to leave the hive will not have lips too swollen to relish the honey." Elaine looks confused. Everyone looks confused. "So . . .," Jane continues, "I think we can also do away with . . ." And so, bit by bit, the list of tasks shrinks. Developers who lose a task sign up for one of the remaining ones.   The negotiation is not painless. Several times, Jane exhibits obvious frustration and impatience. Once, when tensions are especially high, Elaine volunteers, "I'll work extra hard to make up some of the missing time." You are about to correct her when, fortunately, Joe looks her in the eye and says, "When once you proceed down the dark path, forever will it dominate your destiny."   In the end, an iteration acceptable to Jane is reached. It's not what Jane wanted. Indeed, it is significantly less. But it's something the team feels that can be achieved in the next 3 weeks.   And, after all, it still addresses the most important things that Jane wanted in the iteration. "So, Jane," you say when things had quieted down a bit, "when can we expect acceptance tests from you?" Jane sighs. This is the other side of the coin. For every story the development team implements,   Jane must supply a suite of acceptance tests that prove that it works. And the team needs these long before the end of the iteration, since they will certainly point out differences in the way Jane and the developers imagine the system's behaviour.   "I'll get you some example test scripts today," Jane promises. "I'll add to them every day after that. You'll have the entire suite by the middle of the iteration."   * * *   The iteration begins on Monday morning with a flurry of Class, Responsibilities, Collaborators sessions. By midmorning, all the developers have assembled into pairs and are rapidly coding away. "And now, my young apprentice," Joe says to Elaine, "you shall learn the mysteries of test-first design!"   "Wow, that sounds pretty rad," Elaine replies. "How do you do it?" Joe beams. It's clear that he has been anticipating this moment. "OK, what does the code do right now?" "Huh?" replied Elaine, "It doesn't do anything at all; there is no code."   "So, consider our task; can you think of something the code should do?" "Sure," Elaine said with youthful assurance, "First, it should connect to the database." "And thereupon, what must needs be required to connecteth the database?" "You sure talk weird," laughed Elaine. "I think we'd have to get the database object from some registry and call the Connect() method. "Ah, astute young wizard. Thou perceives correctly that we requireth an object within which we can cacheth the database object." "Is 'cacheth' really a word?" "It is when I say it! So, what test can we write that we know the database registry should pass?" Elaine sighs. She knows she'll just have to play along. "We should be able to create a database object and pass it to the registry in a Store() method. And then we should be able to pull it out of the registry with a Get() method and make sure it's the same object." "Oh, well said, my prepubescent sprite!" "Hay!" "So, now, let's write a test function that proves your case." "But shouldn't we write the database object and registry object first?" "Ah, you've much to learn, my young impatient one. Just write the test first." "But it won't even compile!" "Are you sure? What if it did?" "Uh . . ." "Just write the test, Elaine. Trust me." And so Joe, Elaine, and all the other developers began to code their tasks, one test case at a time. The room in which they worked was abuzz with the conversations between the pairs. The murmur was punctuated by an occasional high five when a pair managed to finish a task or a difficult test case.   As development proceeded, the developers changed partners once or twice a day. Each developer got to see what all the others were doing, and so knowledge of the code spread generally throughout the team.   Whenever a pair finished something significant whether a whole task or simply an important part of a task they integrated what they had with the rest of the system. Thus, the code base grew daily, and integration difficulties were minimized.   The developers communicated with Jane on a daily basis. They'd go to her whenever they had a question about the functionality of the system or the interpretation of an acceptance test case.   Jane, good as her word, supplied the team with a steady stream of acceptance test scripts. The team read these carefully and thereby gained a much better understanding of what Jane expected the system to do. By the beginning of the second week, there was enough functionality to demonstrate to Jane. She watched eagerly as the demonstration passed test case after test case. "This is really cool," Jane said as the demonstration finally ended. "But this doesn't seem like one-third of the tasks. Is your velocity slower than anticipated?"   You grimace. You'd been waiting for a good time to mention this to Jane but now she was forcing the issue. "Yes, unfortunately, we are going more slowly than we had expected. The new application server we are using is turning out to be a pain to configure. Also, it takes forever to reboot, and we have to reboot it whenever we make even the slightest change to its configuration."   Jane eyes you with suspicion. The stress of last Monday's negotiations had still not entirely dissipated. She says, "And what does this mean to our schedule? We can't slip it again, we just can't. Russ will have a fit! He'll haul us all into the woodshed and ream us some new ones."   You look Jane right in the eyes. There's no pleasant way to give someone news like this. So you just blurt out, "Look, if things keep going like they're going, we're not going to be done with everything by next Friday. Now it's possible that we'll figure out a way to go faster. But, frankly, I wouldn't depend on that. You should start thinking about one or two tasks that could be removed from the iteration without ruining the demonstration for Russ. Come hell or high water, we are going to give that demonstration on Friday, and I don't think you want us to choose which tasks to omit."   "Aw forchrisakes!" Jane barely manages to stifle yelling that last word as she stalks away, shaking her head. Not for the first time, you say to yourself, "Nobody ever promised me project management would be easy." You are pretty sure it won't be the last time, either.   Actually, things went a bit better than you had hoped. The team did, in fact, have to drop one task from the iteration, but Jane had chosen wisely, and the demonstration for Russ went without a hitch. Russ was not impressed with the progress, but neither was he dismayed. He simply said, "This is pretty good. But remember, we have to be able to demonstrate this system at the trade show in July, and at this rate, it doesn't look like you'll have all that much to show." Jane, whose attitude had improved dramatically with the completion of the iteration, responded to Russ by saying, "Russ, this team is working hard, and well. When July comes around, I am confident that we'll have something significant to demonstrate. It won't be everything, and some of it may be smoke and mirrors, but we'll have something."   Painful though the last iteration was, it had calibrated your velocity numbers. The next iteration went much better. Not because your team got more done than in the last iteration but simply because the team didn't have to remove any tasks or stories in the middle of the iteration.   By the start of the fourth iteration, a natural rhythm has been established. Jane, you, and the team know exactly what to expect from one another. The team is running hard, but the pace is sustainable. You are confident that the team can keep up this pace for a year or more.   The number of surprises in the schedule diminishes to near zero; however, the number of surprises in the requirements does not. Jane and Russ frequently look over the growing system and make recommendations or changes to the existing functionality. But all parties realize that these changes take time and must be scheduled. So the changes do not cause anyone's expectations to be violated. In March, there is a major demonstration of the system to the board of directors. The system is very limited and is not yet in a form good enough to take to the trade show, but progress is steady, and the board is reasonably impressed.   The second release goes even more smoothly than the first. By now, the team has figured out a way to automate Jane's acceptance test scripts. The team has also refactored the design of the system to the point that it is really easy to add new features and change old ones. The second release was done by the end of June and was taken to the trade show. It had less in it than Jane and Russ would have liked, but it did demonstrate the most important features of the system. Although customers at the trade show noticed that certain features were missing, they were very impressed overall. You, Russ, and Jane all returned from the trade show with smiles on your faces. You all felt as though this project was a winner.   Indeed, many months later, you are contacted by Rufus Inc. That company had been working on a system like this for its internal operations. Rufus has canceled the development of that system after a death-march project and is negotiating to license your technology for its environment.   Indeed, things are looking up!

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• Pure Server-Side Filtering with RadGridView and WCF RIA Services

  Those of you who are familiar with WCF RIA Services know that the DomainDataSource control provides a FilterDescriptors collection that enables you to filter data returned by the query on the server. We have been using this DomainDataSource feature in our RIA Services with DomainDataSource online example for almost an year now. In the example, we are listening for RadGridViews Filtering event in order to intercept any filtering that is performed on the client and translate it to something that the DomainDataSource will understand, in this case a System.Windows.Data.FilterDescriptor being added or removed from its FilterDescriptors collection. Think of RadGridView.FilterDescriptors as client-side filtering and of DomainDataSource.FilterDescriptors as server-side filtering. We no longer need the client-side one. With the introduction of the Custom Filtering Controls feature many new possibilities have opened. With these custom controls we no longer need to do any filtering on the client. I have prepared a very small project that demonstrates how to filter solely on the server by using a custom filtering control. As I have already mentioned filtering on the server is done through the FilterDescriptors collection of the DomainDataSource control. This collection holds instances of type System.Windows.Data.FilterDescriptor. The FilterDescriptor has three important properties: PropertyPath: Specifies the name of the property that we want to filter on (the left operand). Operator: Specifies the type of comparison to use when filtering. An instance of FilterOperator Enumeration. Value: The value to compare with (the right operand). An instance of the Parameter Class. By adding filters, you can specify that only entities which meet the condition in the filter are loaded from the domain context. In case you are not familiar with these concepts you might find Brad Abrams blog interesting. Now, our requirements are to create some kind of UI that will manipulate the DomainDataSource.FilterDescriptors collection. When it comes to collections, my first choice of course would be RadGridView. If you are not familiar with the Custom Filtering Controls concept I would strongly recommend getting acquainted with my step-by-step tutorial Custom Filtering with RadGridView for Silverlight and checking the online example out. I have created a simple custom filtering control that contains a RadGridView and several buttons. This control is aware of the DomainDataSource instance, since it is operating on its FilterDescriptors collection. In fact, the RadGridView that is inside it is bound to this collection. In order to display filters that are relevant for the current column only, I have applied a filter to the grid. This filter is a Telerik.Windows.Data.FilterDescriptor and is used to filter the little grid inside the custom control. It should not be confused with the DomainDataSource.FilterDescriptors collection that RadGridView is actually bound to. These are the RIA filters. Additionally, I have added several other features. For example, if you have specified a DataFormatString on your original column, the Value column inside the custom control will pick it up and format the filter values accordingly. Also, I have transferred the data type of the column that you are filtering to the Value column of the custom control. This will help the little RadGridView determine what kind of editor to show up when you begin edit, for example a date picker for DateTime columns. Finally, I have added four buttons two of them can be used to add or remove filters and the other two will communicate the changes you have made to the server. Here is the full source code of the DomainDataSourceFilteringControl. The XAML: <UserControl x:Class="PureServerSideFiltering.DomainDataSourceFilteringControl"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"     xmlns:telerikGrid="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.GridView"     xmlns:telerik="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls"     Width="300">     <Border x:Name="LayoutRoot"             BorderThickness="1"             BorderBrush="#FF8A929E"             Padding="5"             Background="#FFDFE2E5">           <Grid>             <Grid.RowDefinitions>                 <RowDefinition Height="Auto"/>                 <RowDefinition Height="150"/>                 <RowDefinition Height="Auto"/>             </Grid.RowDefinitions>               <StackPanel Grid.Row="0"                         Margin="2"                         Orientation="Horizontal"                         HorizontalAlignment="Center">                 <telerik:RadButton Name="addFilterButton"                                   Click="OnAddFilterButtonClick"                                   Content="Add Filter"                                   Margin="2"                                   Width="96"/>                 <telerik:RadButton Name="removeFilterButton"                                   Click="OnRemoveFilterButtonClick"                                   Content="Remove Filter"                                   Margin="2"                                   Width="96"/>             </StackPanel>               <telerikGrid:RadGridView Name="filtersGrid"                                     Grid.Row="1"                                     Margin="2"                                     ItemsSource="{Binding FilterDescriptors}"                                     AddingNewDataItem="OnFilterGridAddingNewDataItem"                                     ColumnWidth="*"                                     ShowGroupPanel="False"                                     AutoGenerateColumns="False"                                     CanUserResizeColumns="False"                                     CanUserReorderColumns="False"                                     CanUserFreezeColumns="False"                                     RowIndicatorVisibility="Collapsed"                                     IsFilteringAllowed="False"                                     CanUserSortColumns="False">                 <telerikGrid:RadGridView.Columns>                     <telerikGrid:GridViewComboBoxColumn DataMemberBinding="{Binding Operator}"                                                         UniqueName="Operator"/>                     <telerikGrid:GridViewDataColumn Header="Value"                                                     DataMemberBinding="{Binding Value.Value}"                                                     UniqueName="Value"/>                 </telerikGrid:RadGridView.Columns>             </telerikGrid:RadGridView>               <StackPanel Grid.Row="2"                         Margin="2"                         Orientation="Horizontal"                         HorizontalAlignment="Center">                 <telerik:RadButton Name="filterButton"                                   Click="OnApplyFiltersButtonClick"                                   Content="Apply Filters"                                   Margin="2"                                   Width="96"/>                 <telerik:RadButton Name="clearButton"                                   Click="OnClearFiltersButtonClick"                                   Content="Clear Filters"                                   Margin="2"                                   Width="96"/>             </StackPanel>           </Grid>       </Border> </UserControl>   And the code-behind: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; using Telerik.Windows.Controls.GridView; using System.Windows.Data; using Telerik.Windows.Controls; using Telerik.Windows.Data;   namespace PureServerSideFiltering {     /// <summary>     /// A custom filtering control capable of filtering purely server-side.     /// </summary>     public partial class DomainDataSourceFilteringControl : UserControl, IFilteringControl     {         // The main player here.         DomainDataSource domainDataSource;           // This is the name of the property that this column displays.         private string dataMemberName;           // This is the type of the property that this column displays.         private Type dataMemberType;           /// <summary>         /// Identifies the <see cref="IsActive"/> dependency property.         /// </summary>         /// <remarks>         /// The state of the filtering funnel (i.e. full or empty) is bound to this property.         /// </remarks>         public static readonly DependencyProperty IsActiveProperty =             DependencyProperty.Register(                 "IsActive",                 typeof(bool),                 typeof(DomainDataSourceFilteringControl),                 new PropertyMetadata(false));           /// <summary>         /// Gets or sets a value indicating whether the filtering is active.         /// </summary>         /// <remarks>         /// Set this to true if you want to lit-up the filtering funnel.         /// </remarks>         public bool IsActive         {             get { return (bool)GetValue(IsActiveProperty); }             set { SetValue(IsActiveProperty, value); }         }           /// <summary>         /// Gets or sets the domain data source.         /// We need this in order to work on its FilterDescriptors collection.         /// </summary>         /// <value>The domain data source.</value>         public DomainDataSource DomainDataSource         {             get { return this.domainDataSource; }             set { this.domainDataSource = value; }         }           public System.Windows.Data.FilterDescriptorCollection FilterDescriptors         {             get { return this.DomainDataSource.FilterDescriptors; }         }           public DomainDataSourceFilteringControl()         {             InitializeComponent();         }           public void Prepare(GridViewBoundColumnBase column)         {             this.LayoutRoot.DataContext = this;               if (this.DomainDataSource == null)             {                 // Sorry, but we need a DomainDataSource. Can't do anything without it.                 return;             }               // This is the name of the property that this column displays.             this.dataMemberName = column.GetDataMemberName();               // This is the type of the property that this column displays.             // We need this in order to see which FilterOperators to feed to the combo-box column.             this.dataMemberType = column.DataType;               // We will use our magic Type extension method to see which operators are applicable for             // this data type. You can go to the extension method body and see what it does.             ((GridViewComboBoxColumn)this.filtersGrid.Columns["Operator"]).ItemsSource                 = this.dataMemberType.ApplicableFilterOperators();               // This is very nice as well. We will tell the Value column its data type. In this way             // RadGridView will pick up the best editor according to the data type. For example,             // if the data type of the value is DateTime, you will be editing it with a DatePicker.             // Nice!             ((GridViewDataColumn)this.filtersGrid.Columns["Value"]).DataType = this.dataMemberType;               // Yet another nice feature. We will transfer the original DataFormatString (if any) to             // the Value column. In this way if you have specified a DataFormatString for the original             // column, you will see all filter values formatted accordingly.             ((GridViewDataColumn)this.filtersGrid.Columns["Value"]).DataFormatString = column.DataFormatString;               // This is important. Since our little filtersGrid will be bound to the entire collection             // of this.domainDataSource.FilterDescriptors, we need to set a Telerik filter on the             // grid so that it will display FilterDescriptor which are relevane to this column ONLY!             Telerik.Windows.Data.FilterDescriptor columnFilter = new Telerik.Windows.Data.FilterDescriptor("PropertyPath"                 , Telerik.Windows.Data.FilterOperator.IsEqualTo                 , this.dataMemberName);             this.filtersGrid.FilterDescriptors.Add(columnFilter);               // We want to listen for this in order to activate and de-activate the UI funnel.             this.filtersGrid.Items.CollectionChanged += this.OnFilterGridItemsCollectionChanged;         }           /// <summary>         // Since the DomainDataSource is a little bit picky about adding uninitialized FilterDescriptors         // to its collection, we will prepare each new instance with some default values and then         // the user can change them later. Go to the event handler to see how we do this.         /// </summary>         void OnFilterGridAddingNewDataItem(object sender, GridViewAddingNewEventArgs e)         {             // We need to initialize the new instance with some values and let the user go on from here.             System.Windows.Data.FilterDescriptor newFilter = new System.Windows.Data.FilterDescriptor();               // This is a must. It should know what member it is filtering on.             newFilter.PropertyPath = this.dataMemberName;               // Initialize it with one of the allowed operators.             // TypeExtensions.ApplicableFilterOperators method for more info.             newFilter.Operator = this.dataMemberType.ApplicableFilterOperators().First();               if (this.dataMemberType == typeof(DateTime))             {                 newFilter.Value.Value = DateTime.Now;             }             else if (this.dataMemberType == typeof(string))             {                 newFilter.Value.Value = "<enter text>";             }             else if (this.dataMemberType.IsValueType)             {                 // We need something non-null for all value types.                 newFilter.Value.Value = Activator.CreateInstance(this.dataMemberType);             }               // Let the user edit the new filter any way he/she likes.             e.NewObject = newFilter;         }           void OnFilterGridItemsCollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)         {             // We are active only if we have any filters define. In this case the filtering funnel will lit-up.             this.IsActive = this.filtersGrid.Items.Count > 0;         }           private void OnApplyFiltersButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // Comment this if you want the popup to stay open after the button is clicked.             this.ClosePopup();               // Since this.domainDataSource.AutoLoad is false, this will take into             // account all filtering changes that the user has made since the last             // Load() and pull the new data to the client.             this.DomainDataSource.Load();         }           private void OnClearFiltersButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // We want to remove ONLY those filters from the DomainDataSource             // that this control is responsible for.             this.DomainDataSource.FilterDescriptors                 .Where(fd => fd.PropertyPath == this.dataMemberName) // Only "our" filters.                 .ToList()                 .ForEach(fd => this.DomainDataSource.FilterDescriptors.Remove(fd)); // Bye-bye!               // Comment this if you want the popup to stay open after the button is clicked.             this.ClosePopup();               // After we did our housekeeping, get the new data to the client.             this.DomainDataSource.Load();         }           private void OnAddFilterButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // Let the user enter his/or her requirements for a new filter.             this.filtersGrid.BeginInsert();             this.filtersGrid.UpdateLayout();         }           private void OnRemoveFilterButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // Find the currently selected filter and destroy it.             System.Windows.Data.FilterDescriptor filterToRemove = this.filtersGrid.SelectedItem as System.Windows.Data.FilterDescriptor;             if (filterToRemove != null                 && this.DomainDataSource.FilterDescriptors.Contains(filterToRemove))             {                 this.DomainDataSource.FilterDescriptors.Remove(filterToRemove);             }         }           private void ClosePopup()         {             System.Windows.Controls.Primitives.Popup popup = this.ParentOfType<System.Windows.Controls.Primitives.Popup>();             if (popup != null)             {                 popup.IsOpen = false;             }         }     } }   Finally, we need to tell RadGridViews Columns to use this custom control instead of the default one. Here is how to do it: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; using System.Windows.Data; using Telerik.Windows.Data; using Telerik.Windows.Controls; using Telerik.Windows.Controls.GridView;   namespace PureServerSideFiltering {     public partial class MainPage : UserControl     {         public MainPage()         {             InitializeComponent();             this.grid.AutoGeneratingColumn += this.OnGridAutoGeneratingColumn;               // Uncomment this if you want the DomainDataSource to start pre-filtered.             // You will notice how our custom filtering controls will correctly read this information,             // populate their UI with the respective filters and lit-up the funnel to indicate that             // filtering is active. Go ahead and try it.             this.employeesDataSource.FilterDescriptors.Add(new System.Windows.Data.FilterDescriptor("Title", System.Windows.Data.FilterOperator.Contains, "Assistant"));             this.employeesDataSource.FilterDescriptors.Add(new System.Windows.Data.FilterDescriptor("HireDate", System.Windows.Data.FilterOperator.IsGreaterThan, new DateTime(1998, 12, 31)));             this.employeesDataSource.FilterDescriptors.Add(new System.Windows.Data.FilterDescriptor("HireDate", System.Windows.Data.FilterOperator.IsLessThanOrEqualTo, new DateTime(1999, 12, 31)));               this.employeesDataSource.Load();         }           /// <summary>         /// First of all, we will need to replace the default filtering control         /// of each column with out custom filtering control DomainDataSourceFilteringControl         /// </summary>         private void OnGridAutoGeneratingColumn(object sender, GridViewAutoGeneratingColumnEventArgs e)         {             GridViewBoundColumnBase dataColumn = e.Column as GridViewBoundColumnBase;             if (dataColumn != null)             {                 // We do not like ugly dates.                 if (dataColumn.DataType == typeof(DateTime))                 {                     dataColumn.DataFormatString = "{0:d}"; // Short date pattern.                       // Notice how this format will be later transferred to the Value column                     // of the grid that we have inside the DomainDataSourceFilteringControl.                 }                   // Replace the default filtering control with our.                 dataColumn.FilteringControl = new DomainDataSourceFilteringControl()                 {                     // Let the control know about the DDS, after all it will work directly on it.                     DomainDataSource = this.employeesDataSource                 };                   // Finally, lit-up the filtering funnel through the IsActive dependency property                 // in case there are some filters on the DDS that match our column member.                 string dataMemberName = dataColumn.GetDataMemberName();                 dataColumn.FilteringControl.IsActive =                     this.employeesDataSource.FilterDescriptors                     .Where(fd => fd.PropertyPath == dataMemberName)                     .Count() > 0;             }         }     } } The best part is that we are not only writing filters for the DomainDataSource we can read and load them. If the DomainDataSource has some pre-existing filters (like I have created in the code above), our control will read them and will populate its UI accordingly. Even the filtering funnel will light-up! Remember, the funnel is controlled by the IsActive property of our control. While this is just a basic implementation, the source code is absolutely yours and you can take it from here and extend it to match your specific business requirements. Below the main grid there is another debug grid. With its help you can monitor what filter descriptors are added and removed to the domain data source. Download Source Code. (You will have to have the AdventureWorks sample database installed on the default SQLExpress instance in order to run it.) Enjoy!Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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