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  • Adding Output Caching and Expire Header in IIS7 to improve performance

    - by Renso
    The problem: Images and other static files will not be cached unless you tell it to. In IIS7 it is remarkably easy to do this. Web pages are becoming increasingly complex with more scripts, style sheets, images, and Flash on them. A first-time visit to a page may require several HTTP requests to load all the components. By using Expires headers these components become cacheable, which avoids unnecessary HTTP requests on subsequent page views. Expires headers are most often associated with images, but they can and should be used on all page components including scripts, style sheets, and Flash. Every time a page is loaded, every image and other static content like JavaScript files and CSS files will be reloaded on every page request. If the content does not change frequently why not cache it and avoid the network traffic?! The solution: In IIS7 there are two ways to cache content, using the web.config file to set caching for all static content, and in IIS7 itself setting aching by file extension that gives you that extra level of granularity. Web.config: In IIS7, Expires Headers can be enabled in the system.webServer section of the web.config file:   <staticContent>     <clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="1.00:00:00" />   </staticContent> In the above example a cache expiration of 1 day was added. It will be a full day before the content is downloaded from the web server again. To expire the content on a specific date:   <staticContent>     <clientCache cacheControlMode="UseExpires" httpExpires="Sun, 31 Dec 2011 23:59:59 UTC" />   </staticContent> This will expire the content on December 31st 2011 one second before midnight. Issues/Challenges: Once the file has been set to be cached it wont be updated on the user's browser for the set cache expiration. So be careful here with content that may change frequently, like during development. Typically in development you don't want to cache at all for testing purposes. You could also suffix files with timestamp or versions to force a reload into the user's browser cache. IIS7 Expire Web Content Open up your web app in IIS. Open up the sub-folders until you find the folder or file you want to ad an expiration date to. In IIS6 you used to right-click and select properties, no such luck in IIS7, double click HTTP Response. Once the window loads for the HTTP Response Headers, look to the Actions navigation bar to the right, all the way at the top select SET COMMON HEADERS. The Enable HTTP keep-alive will already be pre-selected. Go ahead and add the appropriate expiration header to the file or folder. Note that if you selected a folder, it will apply that setting to all images inside that folder and all nested content, even subfolders. So, two approaches, depending on what level or granularity you need.

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  • Set up a TFS Server/Service demo environment in less than 1 minute now!

    - by Tarun Arora
    Release Notes – http://tfsdemosetup.codeplex.com/  | Download | Source Code | Report a Bug | Ideas To Demonstrate the capabilities of TFS 2012 Server/Service Task board you would need to set up TFS with some teams, a few team members, some sample stories, tasks, etc. That’s too many steps if you as me! Hi! My name is Tarun Arora, I am a Microsoft MVP in Visual Studio ALM & a Visual Studio ALM Ranger, as a consultant I have had to demo TFS Preview to potential customers several times a day. I usually create the team project during the demo to show off how quick and efficient it is, but setting up teams, team members, tasks usually takes longer I don’t prefer carrying out these steps during the demo. I have developed a .net based console application which uses the TFS API to create a standard demo environment saving me from all these manual steps. The console application reads the set up information from an XML file, leaving the setup process highly customizable. Figure 1 – Demo Dictionary, change values here for unique setup The console application today sets up, 1. Create a new Team 2. Set the team as the default team 3. Configure team settings      a. Set Backlog Iteration path      b. Set Team Iterations and start & finish dates      c. Set Team Area path 4. Add Team Members 5. Add Product Backlog Items & linked Tasks. Image 2 – The team website before (on the left) and after (on the right) running the console app Image 3 – Team configuration before (on left) and after (on right) with new team Demo and 2 members Image 4 – Iteration configuration before (on left) and after (on right) with new backlog iteration path & sprint dates set Image 5 – Area configuration (on left) and after (on right) with area path configured for the team   Image 6 – A demo ready Task Board and Task Board for Team Members Credits, - Mattias Sköld [Visual Studio ALM Ranger] – I have used TfsTeamTools to perform team creation & add members - Ivan Popek – TFS 2012 API blog posts had some fantastic reusable samples.  - Shai Raiten [Microsoft ALM MVP] – Great collection of posts on TFS API. Enjoy!

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  • Desktop Fun: Google Themed Icon Packs

    - by Asian Angel
    Are you an avid user of Google’s online services, but the icons for your desktop and app launcher shortcuts leave something to be desired? Now you can make those shortcuts shine with style using our Google Themed Icon Packs collection. Note: To customize the icon setup on your Windows 7 & Vista systems see our article here. Using Windows XP? We have you covered here. Sneak Preview For this week’s sneak preview we set up a Google Chrome themed desktop using the Simply Google Icon Collection shown below. Note: Original full-size wallpaper can be found here. We used Chromium to create a set of app shortcuts for various Google services on our desktop. Anyone who has done the same knows that the original icons do not look very good, so these icon packs can make those shortcuts look spectacular. Once the new icons were arranged for our desktop app shortcuts, we then pinned them to our Taskbar. Those are definitely looking nice! The Icon Packs Simply Google Icon Collection *.ico and .png format Download Google icons *.ico and .png format Download Tango Google Icon Set Vol. 1 *.png and .svg format Download Google Tango Icon Set Vol. 2 *.png and .svg format Download New Google Product Icons *.ico, .png, and .gif format Note: This icon pack contains 657 icons of various sizes. The best selection of individual icon types in the same size (i.e. 48, 128, etc.) from this pack is a mixture of .png and .gif formats. Download New google docs icons *.png format only Download Google Docs pack Icons *.ico, .png, and .gif format Download GCal *.png format only (original favicon .ico file included) Download Google Earth Icon Color Pack *.png format only Download Google Earth Dock Icons *.ico, .png, and .icns format Download Gtalk Color Icons *.png format only Download Google Buzz Icons *.png format only Download Google Chrome icon pack *.png format only Download Google Chrome X *.ico, .png, and .icns format Download Google Chrome icon pack *.png format only Download Wanting more great icon sets to look through? Be certain to visit our Desktop Fun section for more icon goodness! Latest Features How-To Geek ETC How To Boot 10 Different Live CDs From 1 USB Flash Drive The 20 Best How-To Geek Linux Articles of 2010 The 50 Best How-To Geek Windows Articles of 2010 The 20 Best How-To Geek Explainer Topics for 2010 How to Disable Caps Lock Key in Windows 7 or Vista How to Use the Avira Rescue CD to Clean Your Infected PC Enjoy Old School Style Video Game Fun with Chicken Invaders Hide the Twitter “Litter” in Twitter’s Sidebar Area (Chrome and Iron) Public Domain Day: Reflections on Copyright and the Importance of Public Domain Angry Birds Coming to PS3 and PSP This Week I Hate Mondays Wallpaper for That First Day Back at Work Tune Pop Enhances Android Music Notifications

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  • C#/.NET Little Wonders: The Generic Func Delegates

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Back in one of my three original “Little Wonders” Trilogy of posts, I had listed generic delegates as one of the Little Wonders of .NET.  Later, someone posted a comment saying said that they would love more detail on the generic delegates and their uses, since my original entry just scratched the surface of them. Last week, I began our look at some of the handy generic delegates built into .NET with a description of delegates in general, and the Action family of delegates.  For this week, I’ll launch into a look at the Func family of generic delegates and how they can be used to support generic, reusable algorithms and classes. Quick Delegate Recap Delegates are similar to function pointers in C++ in that they allow you to store a reference to a method.  They can store references to either static or instance methods, and can actually be used to chain several methods together in one delegate. Delegates are very type-safe and can be satisfied with any standard method, anonymous method, or a lambda expression.  They can also be null as well (refers to no method), so care should be taken to make sure that the delegate is not null before you invoke it. Delegates are defined using the keyword delegate, where the delegate’s type name is placed where you would typically place the method name: 1: // This delegate matches any method that takes string, returns nothing 2: public delegate void Log(string message); This delegate defines a delegate type named Log that can be used to store references to any method(s) that satisfies its signature (whether instance, static, lambda expression, etc.). Delegate instances then can be assigned zero (null) or more methods using the operator = which replaces the existing delegate chain, or by using the operator += which adds a method to the end of a delegate chain: 1: // creates a delegate instance named currentLogger defaulted to Console.WriteLine (static method) 2: Log currentLogger = Console.Out.WriteLine; 3:  4: // invokes the delegate, which writes to the console out 5: currentLogger("Hi Standard Out!"); 6:  7: // append a delegate to Console.Error.WriteLine to go to std error 8: currentLogger += Console.Error.WriteLine; 9:  10: // invokes the delegate chain and writes message to std out and std err 11: currentLogger("Hi Standard Out and Error!"); While delegates give us a lot of power, it can be cumbersome to re-create fairly standard delegate definitions repeatedly, for this purpose the generic delegates were introduced in various stages in .NET.  These support various method types with particular signatures. Note: a caveat with generic delegates is that while they can support multiple parameters, they do not match methods that contains ref or out parameters. If you want to a delegate to represent methods that takes ref or out parameters, you will need to create a custom delegate. We’ve got the Func… delegates Just like it’s cousin, the Action delegate family, the Func delegate family gives us a lot of power to use generic delegates to make classes and algorithms more generic.  Using them keeps us from having to define a new delegate type when need to make a class or algorithm generic. Remember that the point of the Action delegate family was to be able to perform an “action” on an item, with no return results.  Thus Action delegates can be used to represent most methods that take 0 to 16 arguments but return void.  You can assign a method The Func delegate family was introduced in .NET 3.5 with the advent of LINQ, and gives us the power to define a function that can be called on 0 to 16 arguments and returns a result.  Thus, the main difference between Action and Func, from a delegate perspective, is that Actions return nothing, but Funcs return a result. The Func family of delegates have signatures as follows: Func<TResult> – matches a method that takes no arguments, and returns value of type TResult. Func<T, TResult> – matches a method that takes an argument of type T, and returns value of type TResult. Func<T1, T2, TResult> – matches a method that takes arguments of type T1 and T2, and returns value of type TResult. Func<T1, T2, …, TResult> – and so on up to 16 arguments, and returns value of type TResult. These are handy because they quickly allow you to be able to specify that a method or class you design will perform a function to produce a result as long as the method you specify meets the signature. For example, let’s say you were designing a generic aggregator, and you wanted to allow the user to define how the values will be aggregated into the result (i.e. Sum, Min, Max, etc…).  To do this, we would ask the user of our class to pass in a method that would take the current total, the next value, and produce a new total.  A class like this could look like: 1: public sealed class Aggregator<TValue, TResult> 2: { 3: // holds method that takes previous result, combines with next value, creates new result 4: private Func<TResult, TValue, TResult> _aggregationMethod; 5:  6: // gets or sets the current result of aggregation 7: public TResult Result { get; private set; } 8:  9: // construct the aggregator given the method to use to aggregate values 10: public Aggregator(Func<TResult, TValue, TResult> aggregationMethod = null) 11: { 12: if (aggregationMethod == null) throw new ArgumentNullException("aggregationMethod"); 13:  14: _aggregationMethod = aggregationMethod; 15: } 16:  17: // method to add next value 18: public void Aggregate(TValue nextValue) 19: { 20: // performs the aggregation method function on the current result and next and sets to current result 21: Result = _aggregationMethod(Result, nextValue); 22: } 23: } Of course, LINQ already has an Aggregate extension method, but that works on a sequence of IEnumerable<T>, whereas this is designed to work more with aggregating single results over time (such as keeping track of a max response time for a service). We could then use this generic aggregator to find the sum of a series of values over time, or the max of a series of values over time (among other things): 1: // creates an aggregator that adds the next to the total to sum the values 2: var sumAggregator = new Aggregator<int, int>((total, next) => total + next); 3:  4: // creates an aggregator (using static method) that returns the max of previous result and next 5: var maxAggregator = new Aggregator<int, int>(Math.Max); So, if we were timing the response time of a web method every time it was called, we could pass that response time to both of these aggregators to get an idea of the total time spent in that web method, and the max time spent in any one call to the web method: 1: // total will be 13 and max 13 2: int responseTime = 13; 3: sumAggregator.Aggregate(responseTime); 4: maxAggregator.Aggregate(responseTime); 5:  6: // total will be 20 and max still 13 7: responseTime = 7; 8: sumAggregator.Aggregate(responseTime); 9: maxAggregator.Aggregate(responseTime); 10:  11: // total will be 40 and max now 20 12: responseTime = 20; 13: sumAggregator.Aggregate(responseTime); 14: maxAggregator.Aggregate(responseTime); The Func delegate family is useful for making generic algorithms and classes, and in particular allows the caller of the method or user of the class to specify a function to be performed in order to generate a result. What is the result of a Func delegate chain? If you remember, we said earlier that you can assign multiple methods to a delegate by using the += operator to chain them.  So how does this affect delegates such as Func that return a value, when applied to something like the code below? 1: Func<int, int, int> combo = null; 2:  3: // What if we wanted to aggregate the sum and max together? 4: combo += (total, next) => total + next; 5: combo += Math.Max; 6:  7: // what is the result? 8: var comboAggregator = new Aggregator<int, int>(combo); Well, in .NET if you chain multiple methods in a delegate, they will all get invoked, but the result of the delegate is the result of the last method invoked in the chain.  Thus, this aggregator would always result in the Math.Max() result.  The other chained method (the sum) gets executed first, but it’s result is thrown away: 1: // result is 13 2: int responseTime = 13; 3: comboAggregator.Aggregate(responseTime); 4:  5: // result is still 13 6: responseTime = 7; 7: comboAggregator.Aggregate(responseTime); 8:  9: // result is now 20 10: responseTime = 20; 11: comboAggregator.Aggregate(responseTime); So remember, you can chain multiple Func (or other delegates that return values) together, but if you do so you will only get the last executed result. Func delegates and co-variance/contra-variance in .NET 4.0 Just like the Action delegate, as of .NET 4.0, the Func delegate family is contra-variant on its arguments.  In addition, it is co-variant on its return type.  To support this, in .NET 4.0 the signatures of the Func delegates changed to: Func<out TResult> – matches a method that takes no arguments, and returns value of type TResult (or a more derived type). Func<in T, out TResult> – matches a method that takes an argument of type T (or a less derived type), and returns value of type TResult(or a more derived type). Func<in T1, in T2, out TResult> – matches a method that takes arguments of type T1 and T2 (or less derived types), and returns value of type TResult (or a more derived type). Func<in T1, in T2, …, out TResult> – and so on up to 16 arguments, and returns value of type TResult (or a more derived type). Notice the addition of the in and out keywords before each of the generic type placeholders.  As we saw last week, the in keyword is used to specify that a generic type can be contra-variant -- it can match the given type or a type that is less derived.  However, the out keyword, is used to specify that a generic type can be co-variant -- it can match the given type or a type that is more derived. On contra-variance, if you are saying you need an function that will accept a string, you can just as easily give it an function that accepts an object.  In other words, if you say “give me an function that will process dogs”, I could pass you a method that will process any animal, because all dogs are animals.  On the co-variance side, if you are saying you need a function that returns an object, you can just as easily pass it a function that returns a string because any string returned from the given method can be accepted by a delegate expecting an object result, since string is more derived.  Once again, in other words, if you say “give me a method that creates an animal”, I can pass you a method that will create a dog, because all dogs are animals. It really all makes sense, you can pass a more specific thing to a less specific parameter, and you can return a more specific thing as a less specific result.  In other words, pay attention to the direction the item travels (parameters go in, results come out).  Keeping that in mind, you can always pass more specific things in and return more specific things out. For example, in the code below, we have a method that takes a Func<object> to generate an object, but we can pass it a Func<string> because the return type of object can obviously accept a return value of string as well: 1: // since Func<object> is co-variant, this will access Func<string>, etc... 2: public static string Sequence(int count, Func<object> generator) 3: { 4: var builder = new StringBuilder(); 5:  6: for (int i=0; i<count; i++) 7: { 8: object value = generator(); 9: builder.Append(value); 10: } 11:  12: return builder.ToString(); 13: } Even though the method above takes a Func<object>, we can pass a Func<string> because the TResult type placeholder is co-variant and accepts types that are more derived as well: 1: // delegate that's typed to return string. 2: Func<string> stringGenerator = () => DateTime.Now.ToString(); 3:  4: // This will work in .NET 4.0, but not in previous versions 5: Sequence(100, stringGenerator); Previous versions of .NET implemented some forms of co-variance and contra-variance before, but .NET 4.0 goes one step further and allows you to pass or assign an Func<A, BResult> to a Func<Y, ZResult> as long as A is less derived (or same) as Y, and BResult is more derived (or same) as ZResult. Sidebar: The Func and the Predicate A method that takes one argument and returns a bool is generally thought of as a predicate.  Predicates are used to examine an item and determine whether that item satisfies a particular condition.  Predicates are typically unary, but you may also have binary and other predicates as well. Predicates are often used to filter results, such as in the LINQ Where() extension method: 1: var numbers = new[] { 1, 2, 4, 13, 8, 10, 27 }; 2:  3: // call Where() using a predicate which determines if the number is even 4: var evens = numbers.Where(num => num % 2 == 0); As of .NET 3.5, predicates are typically represented as Func<T, bool> where T is the type of the item to examine.  Previous to .NET 3.5, there was a Predicate<T> type that tended to be used (which we’ll discuss next week) and is still supported, but most developers recommend using Func<T, bool> now, as it prevents confusion with overloads that accept unary predicates and binary predicates, etc.: 1: // this seems more confusing as an overload set, because of Predicate vs Func 2: public static SomeMethod(Predicate<int> unaryPredicate) { } 3: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } 4:  5: // this seems more consistent as an overload set, since just uses Func 6: public static SomeMethod(Func<int, bool> unaryPredicate) { } 7: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } Also, even though Predicate<T> and Func<T, bool> match the same signatures, they are separate types!  Thus you cannot assign a Predicate<T> instance to a Func<T, bool> instance and vice versa: 1: // the same method, lambda expression, etc can be assigned to both 2: Predicate<int> isEven = i => (i % 2) == 0; 3: Func<int, bool> alsoIsEven = i => (i % 2) == 0; 4:  5: // but the delegate instances cannot be directly assigned, strongly typed! 6: // ERROR: cannot convert type... 7: isEven = alsoIsEven; 8:  9: // however, you can assign by wrapping in a new instance: 10: isEven = new Predicate<int>(alsoIsEven); 11: alsoIsEven = new Func<int, bool>(isEven); So, the general advice that seems to come from most developers is that Predicate<T> is still supported, but we should use Func<T, bool> for consistency in .NET 3.5 and above. Sidebar: Func as a Generator for Unit Testing One area of difficulty in unit testing can be unit testing code that is based on time of day.  We’d still want to unit test our code to make sure the logic is accurate, but we don’t want the results of our unit tests to be dependent on the time they are run. One way (of many) around this is to create an internal generator that will produce the “current” time of day.  This would default to returning result from DateTime.Now (or some other method), but we could inject specific times for our unit testing.  Generators are typically methods that return (generate) a value for use in a class/method. For example, say we are creating a CacheItem<T> class that represents an item in the cache, and we want to make sure the item shows as expired if the age is more than 30 seconds.  Such a class could look like: 1: // responsible for maintaining an item of type T in the cache 2: public sealed class CacheItem<T> 3: { 4: // helper method that returns the current time 5: private static Func<DateTime> _timeGenerator = () => DateTime.Now; 6:  7: // allows internal access to the time generator 8: internal static Func<DateTime> TimeGenerator 9: { 10: get { return _timeGenerator; } 11: set { _timeGenerator = value; } 12: } 13:  14: // time the item was cached 15: public DateTime CachedTime { get; private set; } 16:  17: // the item cached 18: public T Value { get; private set; } 19:  20: // item is expired if older than 30 seconds 21: public bool IsExpired 22: { 23: get { return _timeGenerator() - CachedTime > TimeSpan.FromSeconds(30.0); } 24: } 25:  26: // creates the new cached item, setting cached time to "current" time 27: public CacheItem(T value) 28: { 29: Value = value; 30: CachedTime = _timeGenerator(); 31: } 32: } Then, we can use this construct to unit test our CacheItem<T> without any time dependencies: 1: var baseTime = DateTime.Now; 2:  3: // start with current time stored above (so doesn't drift) 4: CacheItem<int>.TimeGenerator = () => baseTime; 5:  6: var target = new CacheItem<int>(13); 7:  8: // now add 15 seconds, should still be non-expired 9: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(15); 10:  11: Assert.IsFalse(target.IsExpired); 12:  13: // now add 31 seconds, should now be expired 14: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(31); 15:  16: Assert.IsTrue(target.IsExpired); Now we can unit test for 1 second before, 1 second after, 1 millisecond before, 1 day after, etc.  Func delegates can be a handy tool for this type of value generation to support more testable code.  Summary Generic delegates give us a lot of power to make truly generic algorithms and classes.  The Func family of delegates is a great way to be able to specify functions to calculate a result based on 0-16 arguments.  Stay tuned in the weeks that follow for other generic delegates in the .NET Framework!   Tweet Technorati Tags: .NET, C#, CSharp, Little Wonders, Generics, Func, Delegates

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  • Finding the lowest average Hamming distance when the order of the strings matter

    - by user1049697
    I have a sequence of binary strings that I want to find a match for among a set of longer sequences of binary strings. A match means that the compared sequence gives the lowest average Hamming distance when all elements in the shorter sequence have been matched against a sequence in one of the longer sets. Let me try to explain with an example. I have a set of video frames that have been hashed using a perceptual hashing algorithm so that the video frames that look the same has roughly the same hash. I want to match a short video clip against a set of longer videos, to see if the clip is contained in one of these. This means that I need to find out where the sequence of the hashed frames in the short video has the lowest average Hamming distance when compared with the long videos. The short video is the sub strings Sub1, Sub2 and Sub3, and I want to match them against the hashes of the long videos in Src. The clue here is that the strings need to match in the specific order that they are given in, e.g. that Sub1 always has to match the element before Sub2, and Sub2 always has to match the element before Sub3. In this example it would map thusly: Sub1-Src3, Sub2-Src4 and Sub3-Src5. So the question is this: is there an algorithm for finding the lowest average Hamming distance when the order of the elements compared matter? The naïve approach to compare the substring sequence to every source string won't cut it of course, so I need something that preferably can match a (much) shorter sub string to a set of million of elements. I have looked at MVP-trees, BK-trees and similar, but everything seems to only take into account one binary string and not a sequence of them. Sub1: 100111011111011101 Sub2: 110111000010010100 Sub3: 111111010110101101 Src1: 001011010001010110 Src2: 010111101000111001 Src3: 101111001110011101 Src4: 010111100011010101 Src5: 001111010110111101 Src6: 101011111111010101 I have added a calculation of the examples below. (The Hamming distances aren't correct, but it doesn't matter) **Run 1.** dist(Sub1, Src1) = 8 dist(Sub2, Src2) = 10 dist(Sub3, Src3) = 12 average = 10 **Run 2.** dist(Sub1, Src2) = 10 dist(Sub2, Src3) = 12 dist(Sub3, Src4) = 10 average = 11 **Run 3.** dist(Sub1, Src3) = 7 dist(Sub2, Src4) = 6 dist(Sub3, Src5) = 10 average = 8 **Run 4.** dist(Sub1, Src3) = 10 dist(Sub2, Src4) = 4 dist(Sub3, Src5) = 2 average = 5 So the winner here is sequence 4 with an average distance of 5.

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  • javascript complex recurrsion [on hold]

    - by Achilles
    Given Below is my data in data array. What i am doing in code below is that from that given data i have to construct json in a special format which i also gave below. //code start here var hierarchy={}; hierarchy.name="Hierarchy"; hierarchy.children=[{"name":"","children":[{"name":"","children":[]}]}]; var countryindex; var flagExist=false; var data = [ {country :"America", city:"Kansas", employe:'Jacob'}, {country :"Pakistan", city:"Lahore", employe:'tahir'}, {country :"Pakistan", city:"Islamabad", employe:'fakhar'} , {country :"Pakistan", city:"Lahore", employe:'bilal'}, {country :"India", city:"d", employe:'ali'} , {country :"Pakistan", city:"Karachi", employe:'eden'}, {country :"America", city:"Kansas", employe:'Jeen'} , {country :"India", city:"Banglore", employe:'PP'} , {country :"India", city:"Banglore", employe:'JJ'} , ]; for(var i=0;i<data.length;i++) { for(var j=0;j<hierarchy.children.length;j++) { //for checking country match if(hierarchy.children[j].name==data[i].country) { countryindex=j; flagExist=true; break; } } if(flagExist)//country match now no need to add new country just add city in it { var cityindex; var cityflag=false; //hierarchy.children[countryindex].children.push({"name":data[i].city,"children":[]}) //if(hierarchy.children[index].children!=undefined) for(var k=0;k< hierarchy.children[countryindex].children.length;k++) { //for checking city match if(hierarchy.children[countryindex].children[k].name==data[i].city) { // hierarchy.children[countryindex].children[k].children.push({"name":data[i].employe}) cityflag=true; cityindex=k; break; } } if(cityflag)//city match now add just empolye at that city index { hierarchy.children[countryindex].children[cityindex].children.push({"name":data[i].employe}); cityflag=false; } else//no city match so add new with employe also as this is new city so its emplye will be 1st { hierarchy.children[countryindex].children.push({"name":data[i].city,children:[{"name":data[i].employe}]}); //same as above //hierarchy.children[countryindex].children[length-1].children.push({"name":data[i].employe}); } flagExist=false; } else{ //no country match adding new country //with city also as this is new city of new country console.log("sparta"); hierarchy.children.push({"name":data[i].country,"children":[{"name":data[i].city,"children":[{"name":data[i].employe}]}]}); // hierarchy.children.children.push({"name":data[i].city,"children":[]}); } //console.log(hierarchy); } hierarchy.children.shift(); var j=JSON.stringify(hierarchy); //code ends here //here is the json which i seccessfully formed from the code { "name":"Hierarchy", "children":[ { "name":"America", "children":[ { "name":"Kansas", "children":[{"name":"Jacob"},{"name":"Jeen"}]}]}, { "name":"Pakistan", "children":[ { "name":"Lahore", "children": [ {"name":"tahir"},{"name":"bilal"}]}, { "name":"Islamabad", "children":[{"name":"fakhar"}]}, { "name":"Karachi", "children":[{"name":"eden"}]}]}, { "name":"India", "children": [ { "name":"d", "children": [ {"name":"ali"}]}, { "name":"Banglore", "children":[{"name":"PP"},{"name":"JJ"}]}]}]} Now the orignal problem is that currently i am solving this problem for data of array of three keys and i have to go for 3 nested loops now i want to optimize this solution so that if data array of object has more than 3 key say 5 {country :"America", state:"NewYork",city:"newYOrk",street:"elm", employe:'Jacob'}, or more than my solution will not work and i cannot decide before how many keys will come so i thought recursion may suit best here. But i am horrible in writing recurrsion and the case is also complex. Can some awesome programmer help me writing recurrsion or suggest some other solution.

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  • How to get my IR remote to work? Lirc can't see it

    - by user1234567
    I'm using Ubuntu 11.10 (amd64) and I'm trying to get my infrared remote control working. The IR device is a part of a DVB-T USB stick (Based on a RTL2832u chip). I'm using these drivers - it's the only way of getting this device to work under 11.10 that I found. It's a big impromevent from previous Ubuntu version, where I had to edit the driver's code. The device works quite great - and the IR part of it works, too. The driver's page says that the code it's in alpha stage, but I'm pretty sure that my issue has nothing to do with that. If, and only if driver's module is loaded with parameter rtl2832u_rc_mode=2 (which means "use NEC protocol for IR") the remote kind of works, I can see this by running cat /dev/.. ../input6 - when I press a button, random letters appear. The remote works just like a keyboard, but keys are totally messed up - when I press '5' the volume goes down, etc. I would like to use Lirc to fix that, but Lirc can't detect my device (i.e. irw shows nothing). I suspect, it's because something gets into control of the device and sets it up as a keyboard. Lirc seems to be working, it's KDE settings module works too, but it just doesn't detect the device. The Lirc page describes this issue, but since 2009 - the last year when that page was updated, Ubuntu moved from HAL (described there) to DeviceKit, rendering provided instruction useless. I had a similar issue with my previous remote, but the keys were not messed up so much - the remote was usable, so I gave up trying to get Lirc working. I tried the answer provided here, but it changed nothing. I also tried forcing lircd to use my device, but this didn't work too: for i in /sys/class/input/input* ; do echo -n "$(basename "$i"): "; cat "$i/name"; done shows input0: Power Button input1: Power Button input2: Logitech Logitech USB Keyboard input3: A4Tech PS/2+USB Mouse input6: IR-receiver inside an USB DVB receiver But when I run: lircd -n --device=name='IR*' as root (also tried with the full name) I always see: lircd-0.9.0[3983]: lircd(default) ready, using /var/run/lirc/lircd lircd-0.9.0[3983]: accepted new client on /var/run/lirc/lircd lircd-0.9.0[3983]: could not get file information for name=IR* lircd-0.9.0[3983]: default_init(): No such file or directory lircd-0.9.0[3983]: Failed to initialize hardware So, how to set up Lirc with devinput driver in such case?

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  • Tellago releases a RESTful API for BizTalk Server business rules

    - by Charles Young
    Jesus Rodriguez has blogged recently on Tellago Devlabs' release of an open source RESTful API for BizTalk Server Business Rules.   This is an excellent addition to the BizTalk ecosystem and I congratulate Tellago on their work.   See http://weblogs.asp.net/gsusx/archive/2011/02/08/tellago-devlabs-a-restful-api-for-biztalk-server-business-rules.aspx   The Microsoft BRE was originally designed to be used as an embedded library in .NET applications. This is reflected in the implementation of the Rules Engine Update (REU) Service which is a TCP/IP service that is hosted by a Windows service running locally on each BizTalk box. The job of the REU is to distribute rules, managed and held in a central database repository, across the various servers in a BizTalk group.   The engine is therefore distributed on each box, rather than exploited behind a central rules service.   This model is all very well, but proves quite restrictive in enterprise environments. The problem is that the BRE can only run legally on licensed BizTalk boxes. Increasingly we need to deliver rules capabilities across a more widely distributed environment. For example, in the project I am working on currently, we need to surface decisioning capabilities for use within WF workflow services running under AppFabric on non-BTS boxes. The BRE does not, currently, offer any centralised rule service facilities out of the box, and hence you have to roll your own (and then run your rules services on BTS boxes which has raised a few eyebrows on my current project, as all other WCF services run on a dedicated server farm ).   Tellago's API addresses this by providing a RESTful API for querying the rules repository and executing rule sets against XML passed in the request payload. As Jesus points out in his post, using a RESTful approach hugely increases the reach of BRE-based decisioning, allowing simple invocation from code written in dynamic languages, mobile devices, etc.   We developed our own SOAP-based general-purpose rules service to handle scenarios such as the one we face on my current project. SOAP is arguably better suited to enterprise service bus environments (please don't 'flame' me - I refuse to engage in the RESTFul vs. SOAP war). For example, on my current project we use claims based authorisation across the entire service bus and use WIF and WS-Federation for this purpose.   We have extended this to the rules service. I can't release the code for commercial reasons :-( but this approach allows us to legally extend the reach of BRE far beyond the confines of the BizTalk boxes on which it runs and to provide general purpose decisioning capabilities on the bus.   So, well done Tellago.   I haven't had a chance to play with the API yet, but am looking forward to doing so.

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  • Windows Azure Recipe: Big Data

    - by Clint Edmonson
    As the name implies, what we’re talking about here is the explosion of electronic data that comes from huge volumes of transactions, devices, and sensors being captured by businesses today. This data often comes in unstructured formats and/or too fast for us to effectively process in real time. Collectively, we call these the 4 big data V’s: Volume, Velocity, Variety, and Variability. These qualities make this type of data best managed by NoSQL systems like Hadoop, rather than by conventional Relational Database Management System (RDBMS). We know that there are patterns hidden inside this data that might provide competitive insight into market trends.  The key is knowing when and how to leverage these “No SQL” tools combined with traditional business such as SQL-based relational databases and warehouses and other business intelligence tools. Drivers Petabyte scale data collection and storage Business intelligence and insight Solution The sketch below shows one of many big data solutions using Hadoop’s unique highly scalable storage and parallel processing capabilities combined with Microsoft Office’s Business Intelligence Components to access the data in the cluster. Ingredients Hadoop – this big data industry heavyweight provides both large scale data storage infrastructure and a highly parallelized map-reduce processing engine to crunch through the data efficiently. Here are the key pieces of the environment: Pig - a platform for analyzing large data sets that consists of a high-level language for expressing data analysis programs, coupled with infrastructure for evaluating these programs. Mahout - a machine learning library with algorithms for clustering, classification and batch based collaborative filtering that are implemented on top of Apache Hadoop using the map/reduce paradigm. Hive - data warehouse software built on top of Apache Hadoop that facilitates querying and managing large datasets residing in distributed storage. Directly accessible to Microsoft Office and other consumers via add-ins and the Hive ODBC data driver. Pegasus - a Peta-scale graph mining system that runs in parallel, distributed manner on top of Hadoop and that provides algorithms for important graph mining tasks such as Degree, PageRank, Random Walk with Restart (RWR), Radius, and Connected Components. Sqoop - a tool designed for efficiently transferring bulk data between Apache Hadoop and structured data stores such as relational databases. Flume - a distributed, reliable, and available service for efficiently collecting, aggregating, and moving large log data amounts to HDFS. Database – directly accessible to Hadoop via the Sqoop based Microsoft SQL Server Connector for Apache Hadoop, data can be efficiently transferred to traditional relational data stores for replication, reporting, or other needs. Reporting – provides easily consumable reporting when combined with a database being fed from the Hadoop environment. Training These links point to online Windows Azure training labs where you can learn more about the individual ingredients described above. Hadoop Learning Resources (20+ tutorials and labs) Huge collection of resources for learning about all aspects of Apache Hadoop-based development on Windows Azure and the Hadoop and Windows Azure Ecosystems SQL Azure (7 labs) Microsoft SQL Azure delivers on the Microsoft Data Platform vision of extending the SQL Server capabilities to the cloud as web-based services, enabling you to store structured, semi-structured, and unstructured data. See my Windows Azure Resource Guide for more guidance on how to get started, including links web portals, training kits, samples, and blogs related to Windows Azure.

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  • Handy SQL Server Function Series: Part 1

    - by Most Valuable Yak (Rob Volk)
    I've been preparing to give a presentation on SQL Server for a while now, and a topic that was recommended was SQL Server functions.  More specifically, the lesser-known functions (like @@OPTIONS), and maybe some interesting ways to use well-known functions (like using PARSENAME to split IP addresses)  I think this is a veritable goldmine of useful information, and researching for the presentation has confirmed that beyond my initial expectations.I even found a few undocumented/underdocumented functions, so for the first official article in this series I thought I'd start with 2 of each, COLLATIONPROPERTY() and COLLATIONPROPERTYFROMID().COLLATIONPROPERTY() provides information about (wait for it) collations, SQL Server's method for handling foreign character sets, sort orders, and case- or accent-sensitivity when sorting character data.  The Books Online entry for  COLLATIONPROPERTY() lists 4 options for code page, locale ID, comparison style and version.  Used in conjunction with fn_helpcollations():SELECT *, COLLATIONPROPERTY(name,'LCID') LCID, COLLATIONPROPERTY(name,'CodePage') CodePage, COLLATIONPROPERTY(name,'ComparisonStyle') ComparisonStyle, COLLATIONPROPERTY(name,'Version') Version FROM fn_helpcollations()You can get some excellent information. (c'mon, be honest, did you even know about fn_helpcollations?)Collations in SQL Server have a unique name and ID, and you'll see one or both in various system tables or views like syscolumns, sys.columns, and INFORMATION_SCHEMA.COLUMNS.  Unfortunately they only link the ID and name for collations of existing columns, so if you wanted to know the collation ID of Albanian_CI_AI_WS, you'd have to declare a column with that collation and query the system table.While poking around the OBJECT_DEFINITION() of sys.columns I found a reference to COLLATIONPROPERTYFROMID(), and the unknown property "Name".  Not surprisingly, this is how sys.columns finds the name of the collation, based on the ID stored in the system tables.  (Check yourself if you don't believe me)Somewhat surprisingly, the "Name" property also works for COLLATIONPROPERTY(), although you'd already know the name at that point.  Some wild guesses and tests revealed that "CollationID" is also a valid property for both functions, so now:SELECT *, COLLATIONPROPERTY(name,'LCID') LCID, COLLATIONPROPERTY(name,'CodePage') CodePage, COLLATIONPROPERTY(name,'ComparisonStyle') ComparisonStyle, COLLATIONPROPERTY(name,'Version') Version, COLLATIONPROPERTY(name,'CollationID') CollationID FROM fn_helpcollations() Will get you the collation ID-name link you…probably didn't know or care about, but if you ever get on Jeopardy! and this question comes up, feel free to send some of your winnings my way. :)And last but not least, COLLATIONPROPERTYFROMID() uses the same properties as COLLATIONPROPERTY(), so you can use either one depending on which value you have available.Keep an eye out for Part 2!

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  • View Link inConsistency

    - by Abhishek Dwivedi
    What is View Link Consistency? When multiple instances (say VO1, VO2, VO3 etc) of an EO-based VO are based on the same underlying EO, a new row created in one of these VO instances (say VO1)can be automatically added (without re-query) to the row sets of the others (VO2, VO3 etc ). This capability is known as the view link consistency. This feature works for any VO for which it is enabled, regardless of whether they are involved in a view link or not. What causes View Link inConsistency? Unless jbo.viewlink.consistent  is disabled for this VO (or globally), or setAssociationConsistent(false) is applied, any of the following can cause View Link inConsistency.  1. setWhereClause 2. Unreferenced secondary EO 3. findByViewCriteria() 4. Using view link accessor row set Why does this happen - View Link inConsistency? Well, there can be one of the following reasons. a. In case of 1 & 2, the view link consistency flag is disabled on that view object. b. As far as 3 is concerned, findByViewCriteria is used to retrieve a new row set to process programmatically without changing the contents of the default row set. In this case, unlike previous cases, the view link consistency flag is not disabled, meaning that the changes in the default row set would be reflected in the new row set.  However, the opposite doesn't hold true. For instance, if a row is deleted from this new row set, the corresponding row in the default row set does not get deleted. In one of my features, which involved deletion of row(s), I resolved the view link inconsistency issue by replacing findByViewCriteria by applyViewCriteria. b. For 4, it's similar to 3 - whenever a view link accessor row set is retrieved, a new row set is created. Now, creating new row set does not mean re-executing the query each time, only creating a new instance of a RowSet object with its default iterator reset to the "slot" before the first row. Also, please note that this new row set always originates from an internally created view object instance, not one you that added to the data model. This internal view object instance is created as needed and added with a system-defined name to the root application module. Anyway, the very reason a distinct, internally-created view object instance is used is to guarantee that it remains unaffected by developer-related changes to their own view objects instances in the data model.

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  • Secret of SQL Trace Duration Column

    - by Dan Guzman
    Why would a trace of long-running queries not show all queries that exceeded the specified duration filter?  We have a server-side SQL Trace that includes RPC:Completed and SQL:BatchCompleted events with a filter on Duration >= 100000.  Nearly all of the queries on this busy OLTP server run in under this 100 millisecond threshold so any that appear in the trace are candidates for root cause analysis and/or performance tuning opportunities. After an application experienced query timeouts, the DBA looked at the trace data to corroborate the problem.  Surprisingly, he found no long-running queries in the trace from the application that experienced the timeouts even though the application’s error log clearly showed detail of the problem (query text, duration, start time, etc.).  The trace did show, however, that there were hundreds of other long-running queries from different applications during the problem timeframe.  We later determined those queries were blocked by a large UPDATE query against a critical table that was inadvertently run during this busy period. So why didn’t the trace include all of the long-running queries?  The reason is because the SQL Trace event duration doesn’t include the time a request was queued while awaiting a worker thread.  Remember that the server was under considerable stress at the time due to the severe blocking episode.  Most of the worker threads were in use by blocked queries and new requests were queued awaiting a worker to free up (a DMV query on the DAC connection will show this queuing: “SELECT scheduler_id, work_queue_count FROM sys.dm_os_schedulers;”).  Technically, those queued requests had not started.  As worker threads became available, queries were dequeued and completed quickly.  These weren’t included in the trace because the duration was under the 100ms duration filter.  The duration reflected the time it took to actually run the query but didn’t include the time queued waiting for a worker thread. The important point here is that duration is not end-to-end response time.  Duration of RPC:Completed and SQL:BatchCompleted events doesn’t include time before a worker thread is assigned nor does it include the time required to return the last result buffer to the client.  In other words, duration only includes time after the worker thread is assigned until the last buffer is filled.  But be aware that duration does include the time need to return intermediate result set buffers back to the client, which is a factor when large query results are returned.  Clients that are slow in consuming results sets can increase the duration value reported by the trace “completed” events.

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  • ADF Code Guidelines

    - by Chris Muir
    During Oracle Open World 2012 the ADF Product Management team announced a new OTN website, the ADF Architecture Square.  While OOW represents a great opportunity to let customers know about new and exciting developments, the problem with making announcements during OOW however is customers are bombarded with so many messages that it's easy to miss something important. So in this blog post I'd like to highlight as part of the ADF Architecture Square website, one of the initial core offerings is a new document entitled ADF Code Guidelines. Now the title of this document should hopefully make it obvious what the document contains, but what's the purpose of the document, why did Oracle create it? Personally having worked as an ADF consultant before joining Oracle, one thing I noted amongst ADF customers who had successfully deployed production systems, that they all approached software development in a professional and engineered way, and all of these customers had their own guideline documents on ADF best practices, conventions and recommendations.  These documents designed to be consumed by their own staff to ensure ADF applications were "built right", typically sourced their guidelines from their team's own expert learnings, and the huge amount of ADF technical collateral that is publicly available.  Maybe from manuals and whitepapers, presentations and blog posts, some written by Oracle and some written by independent sources. Now this is all good and well for the teams that have gone through this effort, gathering all the information and putting it into structured documents, kudos to them.  But for new customers who want to break into the ADF space, who have project pressures to deliver ADF solutions without necessarily working on assembling best practices, creating such a document is understandably (regrettably?) a low priority.  So in recognising this hurdle, at Oracle we've devised the ADF Code Guidelines.  This document sets out ADF code guidelines, practices and conventions for applications built using ADF Business Components and ADF Faces Rich Client (release 11g and greater).  The guidelines are summarized from a number of Oracle documents and other 3rd party collateral, with the goal of giving developers and development teams a short circuit on producing their own best practices collateral. The document is not a final production, but a living document that will be extended to cover new information as discovered or as the ADF framework changes. Readers are encouraged to discuss the guidelines on the ADF EMG and provide constructive feedback to me (Chris Muir) via the ADF EMG Issue Tracker. We hope you'll find the ADF Code Guidelines useful and look forward to providing updates in the near future. Image courtesy of paytai / FreeDigitalPhotos.net

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  • Subterranean IL: Compiling C# exception handlers

    - by Simon Cooper
    An exception handler in C# combines the IL catch and finally exception handling clauses into a single try statement: try { Console.WriteLine("Try block") // ... } catch (IOException) { Console.WriteLine("IOException catch") // ... } catch (Exception e) { Console.WriteLine("Exception catch") // ... } finally { Console.WriteLine("Finally block") // ... } How does this get compiled into IL? Initial implementation If you remember from my earlier post, finally clauses must be specified with their own .try clause. So, for the initial implementation, we take the try/catch/finally, and simply split it up into two .try clauses (I have to use label syntax for this): StartTry: ldstr "Try block" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End EndTry: StartIOECatch: ldstr "IOException catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End EndIOECatch: StartECatch: ldstr "Exception catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End EndECatch: StartFinally: ldstr "Finally block" call void [mscorlib]System.Console::WriteLine(string) // ... endfinally EndFinally: End: // ... .try StartTry to EndTry catch [mscorlib]System.IO.IOException handler StartIOECatch to EndIOECatch catch [mscorlib]System.Exception handler StartECatch to EndECatch .try StartTry to EndTry finally handler StartFinally to EndFinally However, the resulting program isn't verifiable, and doesn't run: [IL]: Error: Shared try has finally or fault handler. Nested try blocks What's with the verification error? Well, it's a condition of IL verification that all exception handling regions (try, catch, filter, finally, fault) of a single .try clause have to be completely contained within any outer exception region, and they can't overlap with any other exception handling clause. In other words, IL exception handling clauses must to be representable in the scoped syntax, and in this example, we're overlapping catch and finally clauses. Not only is this example not verifiable, it isn't semantically correct. The finally handler is specified round the .try. What happens if you were able to run this code, and an exception was thrown? Program execution enters top of try block, and exception is thrown within it CLR searches for an exception handler, finds catch Because control flow is leaving .try, finally block is run The catch block is run leave.s End inside the catch handler branches to End label. We're actually running the finally before the catch! What we do about it What we actually need to do is put the catch clauses inside the finally clause, as this will ensure the finally gets executed at the correct time (this time using scoped syntax): .try { .try { ldstr "Try block" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End } catch [mscorlib]System.IO.IOException { ldstr "IOException catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End } catch [mscorlib]System.Exception { ldstr "Exception catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End } } finally { ldstr "Finally block" call void [mscorlib]System.Console::WriteLine(string) // ... endfinally } End: ret Returning from methods There is a further semantic mismatch that the C# compiler has to deal with; in C#, you are allowed to return from within an exception handling block: public int HandleMethod() { try { // ... return 0; } catch (Exception) { // ... return -1; } } However, you can't ret inside an exception handling block in IL. So the C# compiler does a leave.s to a ret outside the exception handling area, loading/storing any return value to a local variable along the way (as leave.s clears the stack): .method public instance int32 HandleMethod() { .locals init ( int32 retVal ) .try { // ... ldc.i4.0 stloc.0 leave.s End } catch [mscorlib]System.Exception { // ... ldc.i4.m1 stloc.0 leave.s End } End: ldloc.0 ret } Conclusion As you can see, the C# compiler has quite a few hoops to jump through to translate C# code into semantically-correct IL, and hides the numerous conditions on IL exception handling blocks from the C# programmer. Next up: catch-all blocks, and how the runtime deals with non-Exception exceptions.

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  • How to implement efficient Fog of War?

    - by Cambrano
    I've asked a question how to implement Fog Of War(FOW) with shaders. Well I've got this working. I use the vertex color to identify the alpha of a single vertex. I guess the most of you know what the FOW of Age of Empires was like, anyway I'll shortly explain it: You have a map. Everything is unexplored(solid black / 100% transparency) at the beginning. When your NPC's / other game units explore the world (by moving around mostly) they unshadow the map. That means. Everything in a specific radius (viewrange) around a NPC is visible (0%transparency). Anything that is out of viewrange but already explored is visible but shadowed (50% transparency). So yeah, AoE had relatively huge maps. Requirements was something around 100mhz etc. So it should be relatively easy to implement something to solve this problem - actually. Okay. I'm currently adding planes above my world and set the color per vertex. Why do I use many planes ? Unity has a vertex limit of 65.000 per mesh. According to the size of my tiles and the size of my map I need more than one plane. So I actually need a lot of planes. This is obviously pita for my FPS. Well so my question is, what are simple (in sense of performance) techniques to implement a FOW shader? Okay some simplified code what I'm doin so far: // Setup for (int x = 0; x < (Map.Dimension/planeSize); x++) { for (int z = 0; z < (Map.Dimension/planeSize); z++) { CreateMeshAt(x*planeSize, 3, z*planeSize) } } // Explore (is called from NPCs when walking for example) for (int x = ((int) from.x - radius); x < from.x + radius; x ++) { for (int z = ((int) from.z - radius); z < from.z + radius; z ++) { if (from.Distance(x, 1, z) > radius) continue; _transparency[x/tileSize, z/tileSize] = 0.5f; } } // Update foreach(GameObject plane in planes){ foreach(Vector3 vertex in vertices){ Vector3 worldPos = GetWorldPos(vertex); vertex.Color = new Color(0,0,0, _transparency[worldPos.x/tileSize, worldPos.z/tileSize]); } } My shader just sets the transparency of the vertex now, which comes from the vertex color channel

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  • Is throwing an error in unpredictable subclass-specific circumstances a violation of LSP?

    - by Motti Strom
    Say, I wanted to create a Java List<String> (see spec) implementation that uses a complex subsystem, such as a database or file system, for its store so that it becomes a simple persistent collection rather than an basic in-memory one. (We're limiting it specifically to a List of Strings for the purposes of discussion, but it could extended to automatically de-/serialise any object, with some help. We can also provide persistent Sets, Maps and so on in this way too.) So here's a skeleton implementation: class DbBackedList implements List<String> { private DbBackedList() {} /** Returns a list, possibly non-empty */ public static getList() { return new DbBackedList(); } public String get(int index) { return Db.getTable().getRow(i).asString(); // may throw DbExceptions! } // add(String), add(int, String), etc. ... } My problem lies with the fact that the underlying DB API may encounter connection errors that are not specified in the List interface that it should throw. My problem is whether this violates Liskov's Substitution Principle (LSP). Bob Martin actually gives an example of a PersistentSet in his paper on LSP that violates LSP. The difference is that his newly-specified Exception there is determined by the inserted value and so is strengthening the precondition. In my case the connection/read error is unpredictable and due to external factors and so is not technically a new precondition, merely an error of circumstance, perhaps like OutOfMemoryError which can occur even when unspecified. In normal circumstances, the new Error/Exception might never be thrown. (The caller could catch if it is aware of the possibility, just as a memory-restricted Java program might specifically catch OOME.) Is this therefore a valid argument for throwing an extra error and can I still claim to be a valid java.util.List (or pick your SDK/language/collection in general) and not in violation of LSP? If this does indeed violate LSP and thus not practically usable, I have provided two less-palatable alternative solutions as answers that you can comment on, see below. Footnote: Use Cases In the simplest case, the goal is to provide a familiar interface for cases when (say) a database is just being used as a persistent list, and allow regular List operations such as search, subList and iteration. Another, more adventurous, use-case is as a slot-in replacement for libraries that work with basic Lists, e.g if we have a third-party task queue that usually works with a plain List: new TaskWorkQueue(new ArrayList<String>()).start() which is susceptible to losing all it's queue in event of a crash, if we just replace this with: new TaskWorkQueue(new DbBackedList()).start() we get a instant persistence and the ability to share the tasks amongst more than one machine. In either case, we could either handle connection/read exceptions that are thrown, perhaps retrying the connection/read first, or allow them to throw and crash the program (e.g. if we can't change the TaskWorkQueue code).

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  • TomEE Integration in NetBeans Next

    - by Geertjan
    At JavaOne 2013, there was a lot of buzz around the TomEE server, e.g., many Tweets, nice party, and a new TomEE consulting company. For those tracking TomEE developments, it is interesting to note that recently the NetBeans IDE development builds have had added to them... TomEE support. Note: The TomEE support described here is not in NetBeans IDE 7.4, but in development builds for the next release of NetBeans IDE.For example, with NetBeans IDE development builds you're able to: register TomEE as a server in the Services window (TomEE has several distributions, e.g., one can use the "with JAX-RS" one, for example) create a Java EE 6 web project (e.g., Maven based) against this server create JPA entities from database create JAX-RS classes from JPA entities create JSF pages from JPA entities the IDE lets you create a new data source for TomEE and deploy it to the server the IDE figures out the components that are already packaged in TomEE, and the fact that (unlike with regular Tomcat), it does not need to package any components such as JSF implementation, persistence provider, or JAX-RS runtime, so that the resulting WAR file is very small the IDE can also do "deploy on save" with TomEE, so that your development cycle is very fast Adam Bien blogged about how he set up TomEE sometime ago, here. The official support in NetBeans IDE will be much more tightly integrated, simplifying the steps Adam describes. For example, the IDE does step 2 from Adam's blog for you, i.e., it sets up TomEE deployment roles. Moreover, it knows about all the technologies included in TomEE so that it can optimize the packaging; it knows about TomEE's persistence setup; it can work with TomEE data sources, etc. Below you see a Maven-based Java EE 6 PrimeFaces application (all entities and JSF pages generated from a database) deployed to TomEE in NetBeans IDE: And here's the management console for configuring and finetuning TomEE in NetBeans IDE: When I tried out the NetBeans IDE development build and TomEE, to see how everything fits together, I was surprised at how fast TomEE started up. Not sure what they did to it, but seems like a server on steroids. And setting it up in NetBeans IDE was trivial. Add the simple set up of TomEE in NetBeans IDE to the many benefits that the widely praised out of the box NetBeans Maven tools make possible, together with the fact that not one single plugin had to be installed to get everything you see described here up and running... and you have a really powerful combination of dev tools, all for free.

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  • BI&EPM in Focus December 2012

    - by Mike.Hallett(at)Oracle-BI&EPM
    Normal 0 false false false EN-GB X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;} Share with your customers: October Edition of Business Analytics Customer Newsletter (link) Oracle OpenWorld Presentation pdf's available for download (link) OOW Mark Hurd Recap: Business Analytics at Oracle OpenWorld (video | blog) Register your customers for Oracle Days 2012 (link | video) BI & EPM Business Analytics Advisor Webcasts on My.Oracle.Support - Current Schedule and Archived (link) Customers Wüstenrot Efficiently Generates Reports and Analyzes Data with Enterprise Reporting Solution Empresas Públicas Medellin Gathers Data for Annual, Financial Projections 70% Faster ICON Improves Month-End Reporting Significantly Using a Single Source for Timely Consistent Business Intelligence, Reduces Reliance on Spreadsheets  Gilead Sciences, a science-led company backed by business-led IT, uses Oracle solutions to simplify business processes and establish a foundation for continued growth Dell Enhances the Customer Experience with Oracle’s RTD (video) Link to Complete Archive Enterprise Performance Management eBook: Transforming Enterprise Business Planning (link) Blog: Why CFO's should care about Big Data (link) Oracle Hyperion Project Financial Planning - New Projects Feature Release 11.1.2.2 Video Feature Overview. Now Available with many other Hyperion overviews on the YouTube Oracle EPM Channel (link) Available Patch Sets and Patch Set Updates for Oracle Hyperion Enterprise Performance Management Products on My.Oracle.Support (link) Hyperion Disclosure Management supplementary materials provides a set of guides for Disclosure Management and Taxonomy Designer users, including best practices guidelines, a full Disclosure Management sample report, a webinar series, and other guiding materials on My.Oracle.Support (link) See the selection of EPM Customer Videos at MediaNetwork (Hyperion) Business Intelligence Webcast Replay: Big Data, Bright Future, featuring Andrew McAfee (link) Webinar series and guides on Getting Started With Hyperion Interactive Reporting Translation Workbench, a tool that accelerates metadata conversion from IR to Oracle BI Enterprise Edition (OBIEE) on My.Oracle.Support (link) See the selection of BI Customer Videos at MediaNetwork (BI) and for (Exalytics) and (Endeca) ORACLE TEAM USA Analytics Dashboard demo - Now Available (link)

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  • Backup Azure Tables with the Enzo Backup API

    - by Herve Roggero
    In case you missed it, you can now backup (and restore) Azure Tables and SQL Databases using an API directly. The features available through the API can be found here: http://www.bluesyntax.net/backup20api.aspx and the online help for the API is here: http://www.bluesyntax.net/EnzoCloudBackup20/APIIntro.aspx. Backing up Azure Tables can’t be any easier than with the Enzo Backup API. Here is a sample code that does the trick: // Create the backup helper class. The constructor automatically sets the SourceStorageAccount property StorageBackupHelper backup = new StorageBackupHelper("storageaccountname", "storageaccountkey", "sourceStorageaccountname", "sourceStorageaccountkey", true, "apilicensekey"); // Now set some properties… backup.UseCloudAgent = false;                                       // backup locally backup.DeviceURI = @"c:\TMP\azuretablebackup.bkp";    // to this file backup.Override = true; backup.Location = DeviceLocation.LocalFile; // Set optional performance options backup.PKTableStrategy.Mode = BSC.Backup.API.TableStrategyMode.GUID; // Set GUID strategy by default backup.MaxRESTPerSec = 200; // Attempt to stay below 200 REST calls per second // Start the backup now… string taskId = backup.Backup(); // Use the Environment class to get the final status of the operation EnvironmentHelper env = new EnvironmentHelper("storageaccountname", "storageaccountkey", "apilicensekey"); string status = env.GetOperationStatus(taskId);   As you can see above, the code is straightforward. You provide connection settings in the constructor, set a few options indicating where the backup device will be located, set optional performance parameters and start the backup. The performance options are designed to help you backup your Azure Tables quickly, while attempting to keep under a specific threshold to prevent Storage Account throttling. For example, the MaxRESTPerSec property will attempt to keep the overall backup operation under 200 rest calls per second. Another performance option if the Backup Strategy for Azure Tables. By default, all tables are simply scanned. While this works best for smaller Azure Tables, larger tables can use the GUID strategy, which will issue requests against an Azure Table in parallel assuming the PartitionKey stores GUID values. It doesn’t mean that your PartitionKey must have GUIDs however for this strategy to work; but the backup algorithm is tuned for this condition. Other options are available as well, such as filtering which columns, entities or tables are being backed up. Check out more on the Blue Syntax website at http://www.bluesyntax.net.

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  • Set Covering : Runtime hang\error at function call in c

    - by EnthuCrazy
    I am implementing a set covering application which uses cover function int cover(set *skill_list,set *player_list,set *covering) Suppose skill_set={a,b,c,d,e}, player_list={s1,s2,s3} then output coverin ={s1,s3} where say s1={a,b,c}, s3={d,e} and s2={b,d}. Now when I am calling this function it's hanging at run (set_cover.exe stopped working). Here is my cover function: typedef struct Spst_{ void *key; set *st; }Spst; int cover(set *skill_list,set *player_list,set *covering) { Liste *member,*max_member; Spst *subset; set *intersection; void **data; int max_size; set_init(covering); //to initialize set covering initially while(skill_list->size>0&&player_list->size>0) { max_size=0; for(member=player_list->head;member!=NULL;member=member->next) { if(set_intersection(intersection,((Spst *)(member->data))->st,skill_list)!=0) return -1; if(intersection->size>max_size) { max_member=member; max_size=intersection->size; } set_destroy(intersection); //at the end of iteration } if(max_size==0) //to check for no covering return -1; subset=(Spst *)max_member->data; //to insert max subset from play list to covering set set_inselem(covering,subset); for(member=(((Spst *)max_member->data)->st->head);member!=NULL;member=member->next) //to rem elem from skill list { data=(void **)member->data; set_remelem(skill_list,data); } set_remelem(player_list,(void **)subset); //to rem subset from set of subsets play list } if(skill_list->size>0) return -1; return 0; } Now assuming I have defined three set type sets(as stated above) and calling from main as cover(skills,subsets,covering);=> runtime hang Here Please give inputs on the missing link in this or the prerequisites for a proper call to this function type required. EDIT: Assume other functions used in cover are tested and working fine.

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  • Data Auditor by Example

    - by Jinjin.Wang
    OWB has a node Data Auditors under Oracle Module in Projects Navigator. What is data auditor and how to use it? I will give an introduction to data auditor and show its usage by examples. Data auditor is an important tool in ensuring that data quality levels meet business requirements. Data auditor validates data against a set of data rules to determine which records comply and which do not. It gathers statistical metrics on how well the data in a system complies with a rule by auditing and marking how many errors are occurring against the audited table. Data auditors are typically scheduled for regular execution as part of a process flow, to monitor the quality of the data in an operational environment such as a data warehouse or ERP system, either immediately after updates like data loads, or at regular intervals. How to use data auditor to monitor data quality? Only objects with data rules can be monitored, so the first step is to define data rules according to business requirements and apply them to the objects you want to monitor. The objects can be tables, views, materialized views, and external tables. Secondly create a data auditor containing the objects. You can configure the data auditor and set physical deployment parameters for it as optional, which will be used while running the data auditor. Then deploy and run the data auditor either manually or as part of the process flow. After execution, the data auditor sets several output values, and records that are identified as not complying with the defined data rules contained in the data auditor are written to error tables. Here is an example. We have two tables DEPARTMENTS and EMPLOYEES (see pic-1 and pic-2. Click here for DDL and data) imported into OWB. We want to gather statistical metrics on how well data in these two tables satisfies the following requirements: a. Values of the EMPLOYEES.EMPLOYEE_ID attribute are three-digit numbers. b. Valid values for EMPLOYEES.JOB_ID are IT_PROG, SA_REP, SH_CLERK, PU_CLERK, and ST_CLERK. c. EMPLOYEES.EMPLOYEE_ID is related to DEPARTMENTS.MANAGER_ID. Pic-1 EMPLOYEES Pic-2 DEPARTMENTS 1. To determine legal data within EMPLOYEES or legal relationships between data in different columns of the two tables, firstly we define data rules based on the three requirements and apply them to tables. a. The first requirement is about patterns that an attribute is allowed to conform to. We create a Domain Pattern List data rule EMPLOYEE_PATTERN_RULE here. The pattern is defined in the Oracle Database regular expression syntax as ^([0-9]{3})$ Apply data rule EMPLOYEE_PATTERN_RULE to table EMPLOYEES.

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  • SceneManagers as systems in entity system or as a core class used by a system?

    - by Hatoru Hansou
    It seems entity systems are really popular here. Links posted by other users convinced me of the power of such system and I decided to try it. (Well, that and my original code getting messy) In my project, I originally had a SceneManager class that maintained needed logic and structures to organize the scene (QuadTree, 2D game). Before rendering I call selectRect() and pass the x,y of the camera and the width and height of the screen and then obtain a minimized list containing only visible entities ordered from back to front. Now with Systems, originally in my first attempt my Render system required to get added all entities it should handle. This may sound like the correct approach but I realized this was not efficient. Trying to optimize It I reused the SceneManager class internally in the Renderer system, but then I realized I needed methods such as selectRect() in others systems too (AI principally) and make the SceneManager accessible globally again. Currently I converted SceneManager to a system, and ended up with the following interface (only relevant methods): /// Base system interface class System { public: virtual void tick (double delta_time) = 0; // (methods to add and remove entities) }; typedef std::vector<Entity*> EntitiesVector; /// Specialized system interface to allow query the scene class SceneManager: public System { public: virtual EntitiesVector& cull () = 0; /// Sets the entity to be used as the camera and replaces previous ones. virtual void setCamera (Entity* entity) = 0; }; class SceneRenderer // Not a system { vitual void render (EntitiesVector& entities) = 0; }; Also I could not guess how to convert renderers to systems. My game separates logic updates from screen updates, my main class have a tick() method and a render() method that may not be called the same times. In my first attempt renderers were systems but they was saved in a separated manager, updated only in render() and not in tick() like all other systems. I realized that was silly and simply created a SceneRenderer interface and give up about converting them to systems, but that may be for another question. Then... something does not feel right, isn't it? If I understood correctly a system should not depend on another or even count with another system exposing an specific interface. Each system should care only about its entities, or nodes (as optimization, so they have direct references to relevant components without having to constantly call the component() or getComponent() method of the entity).

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  • How do we keep dependent data structures up to date?

    - by Geo
    Suppose you have a parse tree, an abstract syntax tree, and a control flow graph, each one logically derived from the one before. In principle it is easy to construct each graph given the parse tree, but how can we manage the complexity of updating the graphs when the parse tree is modified? We know exactly how the tree has been modified, but how can the change be propagated to the other trees in a way that doesn't become difficult to manage? Naturally the dependent graph can be updated by simply reconstructing it from scratch every time the first graph changes, but then there would be no way of knowing the details of the changes in the dependent graph. I currently have four ways to attempt to solve this problem, but each one has difficulties. Nodes of the dependent tree each observe the relevant nodes of the original tree, updating themselves and the observer lists of original tree nodes as necessary. The conceptual complexity of this can become daunting. Each node of the original tree has a list of the dependent tree nodes that specifically depend upon it, and when the node changes it sets a flag on the dependent nodes to mark them as dirty, including the parents of the dependent nodes all the way down to the root. After each change we run an algorithm that is much like the algorithm for constructing the dependent graph from scratch, but it skips over any clean node and reconstructs each dirty node, keeping track of whether the reconstructed node is actually different from the dirty node. This can also get tricky. We can represent the logical connection between the original graph and the dependent graph as a data structure, like a list of constraints, perhaps designed using a declarative language. When the original graph changes we need only scan the list to discover which constraints are violated and how the dependent tree needs to change to correct the violation, all encoded as data. We can reconstruct the dependent graph from scratch as though there were no existing dependent graph, and then compare the existing graph and the new graph to discover how it has changed. I'm sure this is the easiest way because I know there are algorithms available for detecting differences, but they are all quite computationally expensive and in principle it seems unnecessary so I'm deliberately avoiding this option. What is the right way to deal with these sorts of problems? Surely there must be a design pattern that makes this whole thing almost easy. It would be nice to have a good solution for every problem of this general description. Does this class of problem have a name?

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  • CAM v2.0 ships – all new foundation version

    - by drrwebber
    The latest release of the CAM editor toolset is now available on Sourceforge.net – search NIEM. In this all new version the support from Oracle has enabled a transformation of the editor underpinning Java framework and results in 3x performance improvement and 50% better memory utilization. The result of nearly six months of improvements are catalogued in the release notes. http://sourceforge.net/projects/camprocessor/files/CAM%20Editor/Releases/2.0/CAM_Editor_2-0_Release_Notes.pdf/download However here I’d like to talk about the strategic vision and highlight specific new go to features that make a difference for exchange schema designers and with a focus on the NIEM community. So why is this a foundation version? Basically the new drag and drop designer tool allows you to tailor your own dictionary collection of components and then simply select and position those into your resulting exchange structure. This is true global reuse enabled from a canonical domain dictionary collection. So instead of grappling with XSD Schema syntax, or UML model nuances – this is straightforward direct WYSIWYG visual engineering – using familiar sets of business components. Then the toolkit writes the complex XSD Schema for you, along with test samples, documentation, XMI/UML models, Mindmaps and more. So how do you get a set of business components? The toolkit allows you to harvest these from existing schema collections or enterprise data models, or as in the case of NIEM, existing domain dictionary collections. I’ve been using this for the latest IEEE/OASIS/NIST initiative on a Common Data Format (CDF) for elections management systems. So you can download those from OASIS and see how this can transform how you build actual business exchanges – improving the quality, consistency and usability – and dramatically allowing automated generation of artifacts you only dreamed of before – such as a model of your entire major exchange collection components. http://www.oasis-open.org/committees/documents.php?wg_abbrev=election So what we have here is a foundation version – setting the scene and the basis for changing how people can generate and manage information exchanges. A foundation built using the OASIS CAM standard combined with aspects of the NIEM Naming and Design Rules and the UN/CEFACT Core Components specifications and emerging work on OASIS CIQ name and address and ANSI/ISO code list schema. We still have a raft of work to do to integrate this into SOA best practices and extend the dictionary capabilities to assist true community development. Answering questions such as: - How good is my canonical component collection? - How much reuse is really occurring? - What inconsistencies and extensions are there in the dictionary components? Expect us to begin tackling these areas now that the foundation is in place. The immediate need is to develop training and self-start materials – so we will be focusing there for the next couple of months and especially leading up to the IJIS industry event in July in New Jersey, and the NIEM NTE event in August in Philadelphia. http://sourceforge.net/projects/camprocessor

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  • More on PHP and Oracle 11gR2 Improvements to Client Result Caching

    - by christopher.jones
    Oracle 11.2 brought several improvements to Client Result Caching. CRC is way for the results of queries to be cached in the database client process for reuse.  In an Oracle OpenWorld presentation "Best Practices for Developing Performant Application" my colleague Luxi Chidambaran had a (non-PHP generated) graph for the Niles benchmark that shows a DB CPU reduction up to 600% and response times up to 22% faster when using CRC. Sometimes CRC is called the "Consistent Client Cache" because Oracle automatically invalidates the cache if table data is changed.  This makes it easy to use without needing application logic rewrites. There are a few simple database settings to turn on and tune CRC, so management is also easy. PHP OCI8 as a "client" of the database can use CRC.  The cache is per-process, so plan carefully before caching large data sets.  Tables that are candidates for caching are look-up tables where the network transfer cost dominates. CRC is really easy in 11.2 - I'll get to that in a moment.  It was also pretty easy in Oracle 11.1 but it needed some tiny application changes.  In PHP it was used like: $s = oci_parse($c, "select /*+ result_cache */ * from employees"); oci_execute($s, OCI_NO_AUTO_COMMIT); // Use OCI_DEFAULT in OCI8 <= 1.3 oci_fetch_all($s, $res); I blogged about this in the past.  The query had to include a specific hint that you wanted the results cached, and you needed to turn off auto committing during execution either with the OCI_DEFAULT flag or its new, better-named alias OCI_NO_AUTO_COMMIT.  The no-commit flag rule didn't seem reasonable to me because most people wouldn't be specific about the commit state for a query. Now in Oracle 11.2, DBAs can now nominate tables for caching, either with CREATE TABLE or ALTER TABLE.  That means you don't need the query hint anymore.  As well, the no-commit flag requirement has been lifted.  Your code can now look like: $s = oci_parse($c, "select * from employees"); oci_execute($s); oci_fetch_all($s, $res); Since your code probably already looks like this, your DBA can find the top queries in the database and simply tune the system by turning on CRC in the database and issuing an ALTER TABLE statement for candidate tables.  Voila. Another CRC improvement in Oracle 11.2 is that it works with DRCP connection pooling. There is some fine print about what is and isn't cached, check the Oracle manuals for details.  If you're using 11.1 or non-DRCP "dedicated servers" then make sure you use oci_pconnect() persistent connections.  Also in PHP don't bind strings in the query, although binding as SQLT_INT is OK.

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