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• Questions about identifying the components in MVC

  - by luiscubal

  I'm currently developing an client-server application in node.js, Express, mustache and MySQL. However, I believe this question should be mostly language and framework agnostic. This is the first time I'm doing a real MVC application and I'm having trouble deciding exactly what means each component. (I've done web applications that could perhaps be called MVC before, but I wouldn't confidently refer to them as such) I have a server.js that ties the whole application together. It does initialization of all other components (including the database connection, and what I think are the "models" and the "views"), receiving HTTP requests and deciding which "views" to use. Does this mean that my server.js file is the controller? Or am I mixing code that doesn't belong there? What components should I break the server.js file into? Some examples of code that's in the server.js file: var connection = mysql.createConnection({ host : 'localhost', user : 'root', password : 'sqlrevenge', database : 'blog' }); //... app.get("/login", function (req, res) { //Function handles a GET request for login forms if (process.env.NODE_ENV == 'DEVELOPMENT') { mu.clearCache(); } session.session_from_request(connection, req, function (err, session) { if (err) { console.log('index.js session error', err); session = null; } login_view.html(res, user_model, post_model, session, mu); //I named my view functions "html" for the case I might want to add other output types (such as a JSON API), or should I opt for completely separate views then? }); }); I have another file that belongs named session.js. It receives a cookies object, reads the stored data to decide if it's a valid user session or not. It also includes a function named login that does change the value of cookies. First, I thought it would be part of the controller, since it kind of dealt with user input and supplied data to the models. Then, I thought that maybe it was a model since it dealt with the application data/database and the data it supplies is used by views. Now, I'm even wondering if it could be considered a View, since it outputs data (cookies are part of HTTP headers, which are output)

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• NetBeans IDE 7.3 Knows Null

  - by Geertjan

  What's the difference between these two methods, "test1" and "test2"? public int test1(String str) {     return str.length(); } public int test2(String str) {     if (str == null) {         System.err.println("Passed null!.");         //forgotten return;     }     return str.length(); } The difference, or at least, the difference that is relevant for this blog entry, is that whoever wrote "test2" apparently thinks that the variable "str" may be null, though did not provide a null check. In NetBeans IDE 7.3, you see this hint for "test2", but no hint for "test1", since in that case we don't know anything about the developer's intention for the variable and providing a hint in that case would flood the source code with too many false positives:  Annotations are supported in understanding how a piece of code is intended to be used. If method return types use @Nullable, @NullAllowed, @CheckForNull, the value is considered to be "strongly possible to be null", as well as if the variable is tested to be null, as shown above. When using @NotNull, @NonNull, @Nonnull, the value is considered to be non-null. (The exact FQNs of the annotations are ignored, only simple names are checked.) Here are examples showing where the hints are displayed for the non-null hints (the "strongly possible to be null" hints are not shown below, though you can see one of them in the screenshot above), together with a comment showing what is shown when you hover over the hint: There isn't a "one size fits all" refactoring for these various instances relating to null checks, hence you can't do an automated refactoring across your code base via tools in NetBeans IDE, as shown yesterday for class member reordering across code bases. However, you can, instead, go to Source | Inspect and then do a scan throughout a scope (e.g., current file/package/project or combinations of these or all open projects) for class elements that the IDE identifies as potentially having a problem in this area: Thanks to Jan Lahoda, who reports that this currently also works in NetBeans IDE 7.3 dev builds for fields but that may need to be disabled since right now too many false positives are returned, for help with the info above and any misunderstandings are my own fault!

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• My error with upgrading 4.0 to 4.2- What NOT to do...

  - by Steve Tunstall

  Last week, I was helping a client upgrade from the 2011.1.4.0 code to the newest 2011.1.4.2 code. We downloaded the 4.2 update from MOS, upload and unpacked it on both controllers, and upgraded one of the controllers in the cluster with no issues at all. As this was a brand-new system with no networking or pools made on it yet, there were not any resources to fail back and forth between the controllers. Each controller had it's own, private, management interface (igb0 and igb1) and that's it. So we took controller 1 as the passive controller and upgraded it first. The first controller came back up with no issues and was now on the 4.2 code. Great. We then did a takeover on controller 1, making it the active head (although there were no resources for it to take), and then proceeded to upgrade controller 2. Upon upgrading the second controller, we ran the health check with no issues. We then ran the update and it ran and rebooted normally. However, something strange then happened. It took longer than normal to come back up, and when it did, we got the "cluster controllers on different code" error message that one gets when the two controllers of a cluster are running different code. But we just upgraded the second controller to 4.2, so they should have been the same, right??? Going into the Maintenance-->System screen of controller 2, we saw something very strange. The "current version" was still on 4.0, and the 4.2 code was there but was in the "previous" state with the rollback icon, as if it was the OLDER code and not the newer code. I have never seen this happen before. I would have thought it was a bad 4.2 code file, but it worked just fine with controller 1, so I don't think that was it. Other than the fact the code did not update, there was nothing else going on with this system. It had no yellow lights, no errors in the Problems section, and no errors in any of the logs. It was just out of the box a few hours ago, and didn't even have a storage pool yet. So.... We deleted the 4.2 code, uploaded it from scratch, ran the health check, and ran the upgrade again. once again, it seemed to go great, rebooted, and came back up to the same issue, where it came to 4.0 instead of 4.2. See the picture below.... HERE IS WHERE I MADE A BIG MISTAKE.... I SHOULD have instantly called support and opened a Sev 2 ticket. They could have done a shared shell and gotten the correct Fishwork engineer to look at the files and the code and determine what file was messed up and fixed it. The system was up and working just fine, it was just on an older code version, not really a huge problem at all. Instead, I went ahead and clicked the "Rollback" icon, thinking that the system would rollback to the 4.2 code.   Ouch... What happened was that the system said, "Fine, I will delete the 4.0 code and boot to your 4.2 code"... Which was stupid on my part because something was wrong with the 4.2 code file here and the 4.0 was just fine.  So now the system could not boot at all, and the 4.0 code was completely missing from the system, and even a high-level Fishworks engineer could not help us. I had messed it up good. We could only get to the ILOM, and I had to re-image the system from scratch using a hard-to-get-and-use FishStick USB drive. These are tightly controlled and difficult to get, almost always handcuffed to an engineer who will drive out to re-image a system. This took another day of my client's time.  So.... If you see a "previous version" of your system code which is actually a version higher than the current version... DO NOT ROLL IT BACK.... It did not upgrade for a very good reason. In my case, after the system was re-imaged to a code level just 3 back, we once again tried the same 4.2 code update and it worked perfectly the first time and is now great and stable.  Lesson learned.  By the way, our buddy Ryan Matthews wanted to point out the best practice and supported way of performing an upgrade of an active/active ZFSSA, where both controllers are doing some of the work. These steps would not have helpped me for the above issue, but it's important to follow the correct proceedure when doing an upgrade. 1) Upload software to both controllers and wait for it to unpack 2) On controller "A" navigate to configuration/cluster and click "takeover" 3) Wait for controller "B" to finish restarting, then login to it, navigate to maintenance/system, and roll forward to the new software. 4) Wait for controller "B" to apply the update and finish rebooting 5) Login to controller "B", navigate to configuration/cluster and click "takeover" 6) Wait for controller "A" to finish restarting, then login to it, navigate to maintenance/system, and roll forward to the new software. 7) Wait for controller "A" to apply the update and finish rebooting 8) Login to controller "B", navigate to configuration/cluster and click "failback"

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• Question about BoundingSpheres and Ray intersections

  - by NDraskovic

  I'm working on a XNA project (not really a game) and I'm having some trouble with picking algorithm. I have a few types of 3D models that I draw to the screen, and one of them is a switch. So I'm trying to make a picking algorithm that would enable the user to click on the switch and that would trigger some other function. The problem is that the BoundingSphere.Intersect() method always returns null as result. This is the code I'm using: In the declaration section: ` //Basic matrices private Matrix world = Matrix.CreateTranslation(new Vector3(0, 0, 0)); private Matrix view = Matrix.CreateLookAt(new Vector3(10, 10, 10), new Vector3(0, 0, 0), Vector3.UnitY); private Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45), 800f / 600f, 0.01f, 100f); //Collision detection variables Viewport mainViewport; List<BoundingSphere> spheres = new List<BoundingSphere>(); Ray ControlRay; Vector3 nearPoint, farPoint, nearPlane, farPlane, direction; ` And then in the Update method: ` nearPlane = new Vector3((float)Mouse.GetState().X, (float)Mouse.GetState().Y, 0.0f); farPlane = new Vector3((float)Mouse.GetState().X, (float)Mouse.GetState().Y, 10.0f); nearPoint = GraphicsDevice.Viewport.Unproject(nearPlane, projection, view, world); farPoint = GraphicsDevice.Viewport.Unproject(farPlane, projection, view, world); direction = farPoint - nearPoint; direction.Normalize(); ControlRay = new Ray(nearPoint, direction); if (spheres.Count != 0) { for (int i = 0; i < spheres.Count; i++) { if (spheres[i].Intersects(ControlRay) != null) { Window.Title = spheres[i].Center.ToString(); } else { Window.Title = "Empty"; } } ` The "spheres" list gets filled when the 3D object data gets loaded (I read it from a .txt file). For every object marked as switch (I use simple numbers to determine which object is to be drawn), a BoundingSphere is created (center is on the coordinates of the 3D object, and the diameter is always the same), and added to the list. The objects are drawn normally (and spheres.Count is not 0), I can see them on the screen, but the Window title always says "Empty" (of course this is just for testing purposes, I will add the real function when I get positive results) meaning that there is no intersection between the ControlRay and any of the bounding spheres. I think that my basic matrices (world, view and projection) are making some problems, but I cant figure out what. Please help.

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• Why enumerator structs are a really bad idea (redux)

  - by Simon Cooper

  My previous blog post went into some detail as to why calling MoveNext on a BCL generic collection enumerator didn't quite do what you thought it would. This post covers the Reset method. To recap, here's the simple wrapper around a linked list enumerator struct from my previous post (minus the readonly on the enumerator variable): sealed class EnumeratorWrapper : IEnumerator<int> { private LinkedList<int>.Enumerator m_Enumerator; public EnumeratorWrapper(LinkedList<int> linkedList) { m_Enumerator = linkedList.GetEnumerator(); } public int Current { get { return m_Enumerator.Current; } } object System.Collections.IEnumerator.Current { get { return Current; } } public bool MoveNext() { return m_Enumerator.MoveNext(); } public void Reset() { ((System.Collections.IEnumerator)m_Enumerator).Reset(); } public void Dispose() { m_Enumerator.Dispose(); } } If you have a look at the Reset method, you'll notice I'm having to cast to IEnumerator to be able to call Reset on m_Enumerator. This is because the implementation of LinkedList<int>.Enumerator.Reset, and indeed of all the other Reset methods on the BCL generic collection enumerators, is an explicit interface implementation. However, IEnumerator is a reference type. LinkedList<int>.Enumerator is a value type. That means, in order to call the reset method at all, the enumerator has to be boxed. And the IL confirms this: .method public hidebysig newslot virtual final instance void Reset() cil managed { .maxstack 8 L_0000: nop L_0001: ldarg.0 L_0002: ldfld valuetype [System]System.Collections.Generic.LinkedList`1/Enumerator<int32> EnumeratorWrapper::m_Enumerator L_0007: box [System]System.Collections.Generic.LinkedList`1/Enumerator<int32> L_000c: callvirt instance void [mscorlib]System.Collections.IEnumerator::Reset() L_0011: nop L_0012: ret } On line 0007, we're doing a box operation, which copies the enumerator to a reference object on the heap, then on line 000c calling Reset on this boxed object. So m_Enumerator in the wrapper class is not modified by the call the Reset. And this is the only way to call the Reset method on this variable (without using reflection). Therefore, the only way that the collection enumerator struct can be used safely is to store them as a boxed IEnumerator<T>, and not use them as value types at all.

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• What Precalculus knowledge is required before learning Discrete Math Computer Science topics?

  - by Ein Doofus

  Below I've listed the chapters from a Precalculus book as well as the author recommended Computer Science chapters from a Discrete Mathematics book. Although these chapters are from two specific books on these subjects I believe the topics are generally the same between any Precalc or Discrete Math book. What Precalculus topics should one know before starting these Discrete Math Computer Science topics?: Discrete Mathematics CS Chapters 1.1 Propositional Logic 1.2 Propositional Equivalences 1.3 Predicates and Quantifiers 1.4 Nested Quantifiers 1.5 Rules of Inference 1.6 Introduction to Proofs 1.7 Proof Methods and Strategy 2.1 Sets 2.2 Set Operations 2.3 Functions 2.4 Sequences and Summations 3.1 Algorithms 3.2 The Growths of Functions 3.3 Complexity of Algorithms 3.4 The Integers and Division 3.5 Primes and Greatest Common Divisors 3.6 Integers and Algorithms 3.8 Matrices 4.1 Mathematical Induction 4.2 Strong Induction and Well-Ordering 4.3 Recursive Definitions and Structural Induction 4.4 Recursive Algorithms 4.5 Program Correctness 5.1 The Basics of Counting 5.2 The Pigeonhole Principle 5.3 Permutations and Combinations 5.6 Generating Permutations and Combinations 6.1 An Introduction to Discrete Probability 6.4 Expected Value and Variance 7.1 Recurrence Relations 7.3 Divide-and-Conquer Algorithms and Recurrence Relations 7.5 Inclusion-Exclusion 8.1 Relations and Their Properties 8.2 n-ary Relations and Their Applications 8.3 Representing Relations 8.5 Equivalence Relations 9.1 Graphs and Graph Models 9.2 Graph Terminology and Special Types of Graphs 9.3 Representing Graphs and Graph Isomorphism 9.4 Connectivity 9.5 Euler and Hamilton Ptahs 10.1 Introduction to Trees 10.2 Application of Trees 10.3 Tree Traversal 11.1 Boolean Functions 11.2 Representing Boolean Functions 11.3 Logic Gates 11.4 Minimization of Circuits 12.1 Language and Grammars 12.2 Finite-State Machines with Output 12.3 Finite-State Machines with No Output 12.4 Language Recognition 12.5 Turing Machines Precalculus Chapters R.1 The Real-Number System R.2 Integer Exponents, Scientific Notation, and Order of Operations R.3 Addition, Subtraction, and Multiplication of Polynomials R.4 Factoring R.5 Rational Expressions R.6 Radical Notation and Rational Exponents R.7 The Basics of Equation Solving 1.1 Functions, Graphs, Graphers 1.2 Linear Functions, Slope, and Applications 1.3 Modeling: Data Analysis, Curve Fitting, and Linear Regression 1.4 More on Functions 1.5 Symmetry and Transformations 1.6 Variation and Applications 1.7 Distance, Midpoints, and Circles 2.1 Zeros of Linear Functions and Models 2.2 The Complex Numbers 2.3 Zeros of Quadratic Functions and Models 2.4 Analyzing Graphs of Quadratic Functions 2.5 Modeling: Data Analysis, Curve Fitting, and Quadratic Regression 2.6 Zeros and More Equation Solving 2.7 Solving Inequalities 3.1 Polynomial Functions and Modeling 3.2 Polynomial Division; The Remainder and Factor Theorems 3.3 Theorems about Zeros of Polynomial Functions 3.4 Rational Functions 3.5 Polynomial and Rational Inequalities 4.1 Composite and Inverse Functions 4.2 Exponential Functions and Graphs 4.3 Logarithmic Functions and Graphs 4.4 Properties of Logarithmic Functions 4.5 Solving Exponential and Logarithmic Equations 4.6 Applications and Models: Growth and Decay 5.1 Systems of Equations in Two Variables 5.2 System of Equations in Three Variables 5.3 Matrices and Systems of Equations 5.4 Matrix Operations 5.5 Inverses of Matrices 5.6 System of Inequalities and Linear Programming 5.7 Partial Fractions 6.1 The Parabola 6.2 The Circle and Ellipse 6.3 The Hyperbola 6.4 Nonlinear Systems of Equations

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• WEBLOGIC 12C HANDS-ON BOOTCAMP

  - by agallego

    Oracle PartnerNetwork | Account | Feedback   JOIN THE ORACLE WEBLOGIC PARTNER COMMUNITY AND ATTEND A WEBLOGIC 12C HANDS-ON BOOTCAMP Dear partner As a valued partner we would like to invite you for the WebLogic Partner Community and our WebLogic 12c hands-on Bootcamps – free of charge! Please first login at http://partner.oracle.com and then visit: WebLogic Partner Community. (If you need support with your account please contact the Oracle Partner Business Center). The goal of the WebLogic Partner Community is to provide you with the latest information on Oracle's offerings and to facilitate the exchange of experience within community members. Register Now FREE Assessment vouchers to become certified and WebLogic Server 12c 200 new Features and Training Connect and Network   WebLogic Blogs   WebLogic on Facebook   WebLogic on LinkedIn   WebLogic on Twitter   WebLogic on Oracle Mix WebLogic 12c hands-on Workshops We offer free3 days hands-on WebLogic 12c workshops for Oracle partners who want to become Application Grid Specialized: Register Here! Country Date Location Registration   Germany  3-5 April 2012 Oracle Düsseldorf Click here   France  24-26 April 2012 Oracle Colombes Click here   Spain 08-10 May 2012  Oracle Madrid  Click here   Netherlands  22-24 May 2012  Oracle Amsterdam  Click here   United Kingdom  06-08 June 2012  Oracle Reading  Click here   Italy  19-21 June 2012  Oracle Cinisello Balsamo  Click here   Portugal  10-12 July 2012  Oracle Lisbon  Click here Skill requirements Attendees need to have the following skills as this is required by the product-set and to make sure they get the most out of the training: Basic knowledge in Java and JavaEE Understanding the Application Server concept Basic knowledge in older releases of WebLogic Server would be beneficial Member of WebLogic Partner Community for registration please vist http://www.oracle.com/partners/goto/wls-emea Hardware requirements Every participant works on his own notebook. The minimal hardware requirements are: 4Gb physical RAM (we will boot the image with 2Gb RAM)  dual core CPU 15 GB HD Software requirements Please install Oracle VM VirtualBox 4.1.8 Follow-up and certification  With the workshop registration you agree to the following next steps Follow-up training attend and pass the Oracle Application Grid Certified Implementation Specialist Registration For details and registration please visit Register Here Free WebLogic Certification (Free assessment voucher to become certified) For all WebLogic experts, we offer free vouchers worth $195 for the Oracle Application Grid Certified Implementation Specialist assessment. To demonstrate your WebLogic knowledge you first have to pass the free online assessment Oracle Application Grid PreSales Specialist. For free vouchers, please send an e-mail with the screenshot of your Oracle Application Grid PreSales certirficate to [email protected] including your Name, Company, E-mail and Country. Note: This offer is limited to partners from Europe Middle East and Africa. Partners from other countries please contact your Oracle partner manager. WebLogic Specialization To become specialized in Application Grid, please make sure that you access the: Application Grid Specialization Guide Application Grid Specialization Checklist If you have any questions please contact the Oracle Partner Business Center. Oracle WebLogic Server 12c Key New Capabilities Java EE 6 and Developer Productivity Simplified Deployment and Management with Virtualization Integrated Traffic Management Enhanced High Availability and Disaster Recovery Much Higher Performance For more information please visit: Presentation from the WebLogic 12c launch Technical Presentation from the WebLogic 12c launch WebLogic OTN Website WebLogic 12c Virtual Conference Environment WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea (OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Best regards, Jürgen Kress WebLogic Partner Adoption EMEA Tel. +49 89 1430 1479 E-Mail: [email protected]   Copyright © 2012, Oracle and/or its affiliates. All rights reserved. Contact PBC | Legal Notices and Terms of Use | Privacy Statement Oracle Corporation - Worldwide Headquarters, 500 Oracle Parkway, OPL - E-mail Services, Redwood Shores, CA 94065, United States Your privacy is important to us. You can login to your account to update your e-mail subscriptions or you can opt-out of all Oracle Marketing e-mails at any time. Please note that opting-out of Marketing communications does not affect your receipt of important business communications related to your current relationship with Oracle such as Security Updates, Event Registration notices, Account Management and Support/Service communications.

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• Taking the Plunge - or Dipping Your Toe - into the Fluffy IAM Cloud by Paul Dhanjal (Simeio Solutions)

  - by Greg Jensen

  In our last three posts, we’ve examined the revolution that’s occurring today in identity and access management (IAM). We looked at the business drivers behind the growth of cloud-based IAM, the shortcomings of the old, last-century IAM models, and the new opportunities that federation, identity hubs and other new cloud capabilities can provide by changing the way you interact with everyone who does business with you. In this, our final post in the series, we’ll cover the key things you, the enterprise architect, should keep in mind when considering moving IAM to the cloud. Invariably, what starts the consideration process is a burning business need: a compliance requirement, security vulnerability or belt-tightening edict. Many on the business side view IAM as the “silver bullet” – and for good reason. You can almost always devise a solution using some aspect of IAM. The most critical question to ask first when using IAM to address the business need is, simply: is my solution complete? Typically, “business” is not focused on the big picture. Understandably, they’re focused instead on the need at hand: Can we be HIPAA compliant in 6 months? Can we tighten our new hire, employee transfer and termination processes? What can we do to prevent another password breach? Can we reduce our service center costs by the end of next quarter? The business may not be focused on the complete set of services offered by IAM but rather a single aspect or two. But it is the job – indeed the duty – of the enterprise architect to ensure that all aspects are being met. It’s like remodeling a house but failing to consider the impact on the foundation, the furnace or the zoning or setback requirements. While the homeowners may not be thinking of such things, the architect, of course, must. At Simeio Solutions, the way we ensure that all aspects are being taken into account – to expose any gaps or weaknesses – is to assess our client’s IAM capabilities against a five-step maturity model ranging from “ad hoc” to “optimized.” The model we use is similar to Capability Maturity Model Integration (CMMI) developed by the Software Engineering Institute (SEI) at Carnegie Mellon University. It’s based upon some simple criteria, which can provide a visual representation of how well our clients fair when evaluated against four core categories: ·         Program Governance ·         Access Management (e.g., Single Sign-On) ·         Identity and Access Governance (e.g., Identity Intelligence) ·         Enterprise Security (e.g., DLP and SIEM) Often our clients believe they have a solution with all the bases covered, but the model exposes the gaps or weaknesses. The gaps are ideal opportunities for the cloud to enter into the conversation. The complete process is straightforward: 1.    Look at the big picture, not just the immediate need – what is our roadmap and how does this solution fit? 2.    Determine where you stand with respect to the four core areas – what are the gaps? 3.    Decide how to cover the gaps – what role can the cloud play? Returning to our home remodeling analogy, at some point, if gaps or weaknesses are discovered when evaluating the complete impact of the proposed remodel – if the existing foundation wouldn’t support the new addition, for example – the owners need to decide if it’s time to move to a new house instead of trying to remodel the old one. However, with IAM it’s not an either-or proposition – i.e., either move to the cloud or fix the existing infrastructure. It’s possible to use new cloud technologies just to cover the gaps. Many of our clients start their migration to the cloud this way, dipping in their toe instead of taking the plunge all at once. Because our cloud services offering is based on the Oracle Identity and Access Management Suite, we can offer a tremendous amount of flexibility in this regard. The Oracle platform is not a collection of point solutions, but rather a complete, integrated, best-of-breed suite. Yet it’s not an all-or-nothing proposition. You can choose just the features and capabilities you need using a pay-as-you-go model, incrementally turning on and off services as needed. Better still, all the other capabilities are there, at the ready, whenever you need them. Spooling up these cloud-only services takes just a fraction of the time it would take a typical organization to deploy internally. SLAs in the cloud may be higher than on premise, too. And by using a suite of software that’s complete and integrated, you can dramatically lower cost and complexity. If your in-house solution cannot be migrated to the cloud, you might consider using hardware appliances such as Simeio’s Cloud Interceptor to extend your enterprise out into the network. You might also consider using Expert Managed Services. Cost is usually the key factor – not just development costs but also operational sustainment costs. Talent or resourcing issues often come into play when thinking about sustaining a program. Expert Managed Services such as those we offer at Simeio can address those concerns head on. In a cloud offering, identity and access services lend to the new paradigms described in my previous posts. Most importantly, it allows us all to focus on what we're meant to do – provide value, lower costs and increase security to our respective organizations. It’s that magic “silver bullet” that business knew you had all along. If you’d like to talk more, you can find us at simeiosolutions.com.

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• Data Transformation Pipeline

  - by davenewza

  I have create some kind of data pipeline to transform coordinate data into more useful information. Here is the shell of pipeline: public class PositionPipeline { protected List<IPipelineComponent> components; public PositionPipeline() { components = new List<IPipelineComponent>(); } public PositionPipelineEntity Process(Position position) { foreach (var component in components) { position = component.Execute(position); } return position; } public PositionPipeline RegisterComponent(IPipelineComponent component) { components.Add(component); return this; } } Every IPipelineComponent accepts and returns the same type - a PositionPipelineEntity. Code: public interface IPipelineComponent { PositionPipelineEntity Execute(PositionPipelineEntity position); } The PositionPipelineEntity needs to have many properties, many which are unused in certain components and required in others. Some properties will also have become redundant at the end of the pipeline. For example, these components could be executed: TransformCoordinatesComponent: Parse the raw coordinate data into a Coordinate type. DetermineCountryComponent: Determine and stores country code. DetermineOnRoadComponent: Determine and store whether coordinate is on a road. Code: pipeline .RegisterComponent(new TransformCoordinatesComponent()) .RegisterComponent(new DetermineCountryComponent()) .RegisterComponent(new DetermineOnRoadComponent()); pipeline.Process(positionPipelineEntity); The PositionPipelineEntity type: public class PositionPipelineEntity { // Only relevant to the TransformCoordinatesComponent public decimal RawCoordinateLatitude { get; set; } // Only relevant to the TransformCoordinatesComponent public decimal RawCoordinateLongitude { get; set; } // Required by all components after TransformCoordinatesComponent public Coordinate CoordinateLatitude { get; set; } // Required by all components after TransformCoordinatesComponent public Coordinate CoordinateLongitude { get; set; } // Set in DetermineCountryComponent, not required anywhere. // Requires CoordinateLatitude and CoordinateLongitude (TransformCoordinatesComponent) public string CountryCode { get; set; } // Set in DetermineOnRoadComponent, not required anywhere. // Requires CoordinateLatitude and CoordinateLongitude (TransformCoordinatesComponent) public bool OnRoad { get; set; } } Problems: I'm very concerned about the dependency that a component has on properties. The way to solve this would be to create specific types for each component. The problem then is that I cannot chain them together like this. The other problem is the order of components in the pipeline matters. There is some dependency. The current structure does not provide any static or runtime checking for such a thing. Any feedback would be appreciated.

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• How do you automate a SharePoint 2010 deployment?

  - by Enrique Lima

  In the last couple of months SharePoint traffic (consulting, training and speaking) has picked up.  And with that also the requests for deployments.  There are good, great, bad and really bad things around this. But that is for another topic.  However part of the good and great has been the fact of organizations wanting to do a proof of concept deployment (even when WSS or MOSS has been deployed). We can go through a session (Microsoft has the SDPS concept, SharePoint Deployment Planning Services) of discovering what the customer wants to achieve from their investment in the platform and then also proceed to model the solution that would fit their needs.  But it should not stop there.  The next step should be a POC (as many have requested) to test out. Now, on to the meat of this post.  How do I deploy?  While it is a good process to watch and see all of it take place, not many have the time to sit through that.  Even more so, when that has been part of the description of deploying the platform in the sessions mentioned above. I will, though, break it into a deployment for development purposes and a deployment of a farm. Two tools (or scripts) for those two different types of deployment. First, let me address the development environment.  Around the last week in October, Chris Johnson (SharePoint Product Team) announced a SharePoint Easy Setup for Developers.  The kit itself will assist you in installing SharePoint Server (in standalone mode), the tools that go around Visual Studio, Expression Studio and the Office 2010 tools. Here is the link to Chris’ post: http://blogs.msdn.com/b/cjohnson/archive/2010/10/28/announcing-sharepoint-easy-setup-for-developers.aspx The other scenario is the use of a script in assisting you through the deployment of a farm. Now, this is not to override planning.  It should highlight the need for planning even more.  How?  Having your service accounts planned, the structure of the sites and the scale of your deployment.  Enter AutoSPInstaller.  This is a CodePlex project, and the intent behind this is not only to automate the installation but to give some meaning and get some sense out of what goes on during a SharePoint deployment. How?  Take for example the creation of the databases, when we do the initial OOB deployment by using the wizard, more times than not, we leave the names as they are.  How is that a “bad thing”?  Let’s make it a better practice to rename those Databases, and have them take on a name that is not “GUID-ized”. Having a better naming convention will not hurt, on the other hand will allow for consistency. Here is the link to AutoSPInstaller’s site on CodePlex: http://autospinstaller.codeplex.com/

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• High Availability for IaaS, PaaS and SaaS in the Cloud

  - by BuckWoody

  Outages, natural disasters and unforeseen events have proved that even in a distributed architecture, you need to plan for High Availability (HA). In this entry I'll explain a few considerations for HA within Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). In a separate post I'll talk more about Disaster Recovery (DR), since each paradigm has a different way to handle that. Planning for HA in IaaS IaaS involves Virtual Machines - so in effect, an HA strategy here takes on many of the same characteristics as it would on-premises. The primary difference is that the vendor controls the hardware, so you need to verify what they do for things like local redundancy and so on from the hardware perspective. As far as what you can control and plan for, the primary factors fall into three areas: multiple instances, geographical dispersion and task-switching. In almost every cloud vendor I've studied, to ensure your application will be protected by any level of HA, you need to have at least two of the Instances (VM's) running. This makes sense, but you might assume that the vendor just takes care of that for you - they don't. If a single VM goes down (for whatever reason) then the access to it is lost. Depending on multiple factors, you might be able to recover the data, but you should assume that you can't. You should keep a sync to another location (perhaps the vendor's storage system in another geographic datacenter or to a local location) to ensure you can continue to serve your clients. You'll also need to host the same VM's in another geographical location. Everything from a vendor outage to a network path problem could prevent your users from reaching the system, so you need to have multiple locations to handle this. This means that you'll have to figure out how to manage state between the geo's. If the system goes down in the middle of a transaction, you need to figure out what part of the process the system was in, and then re-create or transfer that state to the second set of systems. If you didn't write the software yourself, this is non-trivial. You'll also need a manual or automatic process to detect the failure and re-route the traffic to your secondary location. You could flip a DNS entry (if your application can tolerate that) or invoke another process to alias the first system to the second, such as load-balancing and so on. There are many options, but all of them involve coding the state into the application layer. If you've simply moved a state-ful application to VM's, you may not be able to easily implement an HA solution. Planning for HA in PaaS Implementing HA in PaaS is a bit simpler, since it's built on the concept of stateless applications deployment. Once again, you need at least two copies of each element in the solution (web roles, worker roles, etc.) to remain available in a single datacenter. Also, you need to deploy the application again in a separate geo, but the advantage here is that you could work out a "shared storage" model such that state is auto-balanced across the world. In fact, you don't have to maintain a "DR" site, the alternate location can be live and serving clients, and only take on extra load if the other site is not available. In Windows Azure, you can use the Traffic Manager service top route the requests as a type of auto balancer. Even with these benefits, I recommend a second backup of storage in another geographic location. Storage is inexpensive; and that second copy can be used for not only HA but DR. Planning for HA in SaaS In Software-as-a-Service (such as Office 365, or Hadoop in Windows Azure) You have far less control over the HA solution, although you still maintain the responsibility to ensure you have it. Since each SaaS is different, check with the vendor on the solution for HA - and make sure you understand what they do and what you are responsible for. They may have no HA for that solution, or pin it to a particular geo, or perhaps they have a massive HA built in with automatic load balancing (which is often the case).   All of these options (with the exception of SaaS) involve higher costs for the design. Do not sacrifice reliability for cost - that will always cost you more in the end. Build in the redundancy and HA at the very outset of the project - if you try to tack it on later in the process the business will push back and potentially not implement HA. References: http://www.bing.com/search?q=windows+azure+High+Availability  (each type of implementation is different, so I'm routing you to a search on the topic - look for the "Patterns and Practices" results for the area in Azure you're interested in)

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• Performance triage

  - by Dave

  Folks often ask me how to approach a suspected performance issue. My personal strategy is informed by the fact that I work on concurrency issues. (When you have a hammer everything looks like a nail, but I'll try to keep this general). A good starting point is to ask yourself if the observed performance matches your expectations. Expectations might be derived from known system performance limits, prototypes, and other software or environments that are comparable to your particular system-under-test. Some simple comparisons and microbenchmarks can be useful at this stage. It's also useful to write some very simple programs to validate some of the reported or expected system limits. Can that disk controller really tolerate and sustain 500 reads per second? To reduce the number of confounding factors it's better to try to answer that question with a very simple targeted program. And finally, nothing beats having familiarity with the technologies that underlying your particular layer. On the topic of confounding factors, as our technology stacks become deeper and less transparent, we often find our own technology working against us in some unexpected way to choke performance rather than simply running into some fundamental system limit. A good example is the warm-up time needed by just-in-time compilers in Java Virtual Machines. I won't delve too far into that particular hole except to say that it's rare to find good benchmarks and methodology for java code. Another example is power management on x86. Power management is great, but it can take a while for the CPUs to throttle up from low(er) frequencies to full throttle. And while I love "turbo" mode, it makes benchmarking applications with multiple threads a chore as you have to remember to turn it off and then back on otherwise short single-threaded runs may look abnormally fast compared to runs with higher thread counts. In general for performance characterization I disable turbo mode and fix the power governor at "performance" state. Another source of complexity is the scheduler, which I've discussed in prior blog entries. Lets say I have a running application and I want to better understand its behavior and performance. We'll presume it's warmed up, is under load, and is an execution mode representative of what we think the norm would be. It should be in steady-state, if a steady-state mode even exists. On Solaris the very first thing I'll do is take a set of "pstack" samples. Pstack briefly stops the process and walks each of the stacks, reporting symbolic information (if available) for each frame. For Java, pstack has been augmented to understand java frames, and even report inlining. A few pstack samples can provide powerful insight into what's actually going on inside the program. You'll be able to see calling patterns, which threads are blocked on what system calls or synchronization constructs, memory allocation, etc. If your code is CPU-bound then you'll get a good sense where the cycles are being spent. (I should caution that normal C/C++ inlining can diffuse an otherwise "hot" method into other methods. This is a rare instance where pstack sampling might not immediately point to the key problem). At this point you'll need to reconcile what you're seeing with pstack and your mental model of what you think the program should be doing. They're often rather different. And generally if there's a key performance issue, you'll spot it with a moderate number of samples. I'll also use OS-level observability tools to lock for the existence of bottlenecks where threads contend for locks; other situations where threads are blocked; and the distribution of threads over the system. On Solaris some good tools are mpstat and too a lesser degree, vmstat. Try running "mpstat -a 5" in one window while the application program runs concurrently. One key measure is the voluntary context switch rate "vctx" or "csw" which reflects threads descheduling themselves. It's also good to look at the user; system; and idle CPU percentages. This can give a broad but useful understanding if your threads are mostly parked or mostly running. For instance if your program makes heavy use of malloc/free, then it might be the case you're contending on the central malloc lock in the default allocator. In that case you'd see malloc calling lock in the stack traces, observe a high csw/vctx rate as threads block for the malloc lock, and your "usr" time would be less than expected. Solaris dtrace is a wonderful and invaluable performance tool as well, but in a sense you have to frame and articulate a meaningful and specific question to get a useful answer, so I tend not to use it for first-order screening of problems. It's also most effective for OS and software-level performance issues as opposed to HW-level issues. For that reason I recommend mpstat & pstack as my the 1st step in performance triage. If some other OS-level issue is evident then it's good to switch to dtrace to drill more deeply into the problem. Only after I've ruled out OS-level issues do I switch to using hardware performance counters to look for architectural impediments.

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• Is code like this a "train wreck" (in violation of Law of Demeter)?

  - by Michael Kjörling

  Browsing through some code I've written, I came across the following construct which got me thinking. At a first glance, it seems clean enough. Yes, in the actual code the getLocation() method has a slightly more specific name which better describes exactly which location it gets. service.setLocation(this.configuration.getLocation().toString()); In this case, service is an instance variable of a known type, declared within the method. this.configuration comes from being passed in to the class constructor, and is an instance of a class implementing a specific interface (which mandates a public getLocation() method). Hence, the return type of the expression this.configuration.getLocation() is known; specifically in this case, it is a java.net.URL, whereas service.setLocation() wants a String. Since the two types String and URL are not directly compatible, some sort of conversion is required to fit the square peg in the round hole. However, according to the Law of Demeter as cited in Clean Code, a method f in class C should only call methods on C, objects created by or passed as arguments to f, and objects held in instance variables of C. Anything beyond that (the final toString() in my particular case above, unless you consider a temporary object created as a result of the method invocation itself, in which case the whole Law seems to be moot) is disallowed. Is there a valid reasoning why a call like the above, given the constraints listed, should be discouraged or even disallowed? Or am I just being overly nitpicky? If I were to implement a method URLToString() which simply calls toString() on a URL object (such as that returned by getLocation()) passed to it as a parameter, and returns the result, I could wrap the getLocation() call in it to achieve exactly the same result; effectively, I would just move the conversion one step outward. Would that somehow make it acceptable? (It seems to me, intuitively, that it should not make any difference either way, since all that does is move things around a little. However, going by the letter of the Law of Demeter as cited, it would be acceptable, since I would then be operating directly on a parameter to a function.) Would it make any difference if this was about something slightly more exotic than calling toString() on a standard type? When answering, do keep in mind that altering the behavior or API of the type that the service variable is of is not practical. Also, for the sake of argument, let's say that altering the return type of getLocation() is also impractical.

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• How do I organize a GUI application for passing around events and for setting up reads from a shared resource

  - by Savanni D'Gerinel

  My tools involved here are GTK and Haskell. My questions are probably pretty trivial for anyone who has done significant GUI work, but I've been off in the equivalent of CGI applications for my whole career. I'm building an application that displays tabular data, displays the same data in a graph form, and has an edit field for both entering new data and for editing existing data. After asking about sharing resources, I decided that all of the data involved will be stored in an MVar so that every component can just read the current state from the MVar. All of that works, but now it is time for me to rearrange the application so that it can be interactive. With that in mind, I have three widgets: a TextView (for editing), a TreeView (for displaying the data), and a DrawingArea (for displaying the data as a graph). I THINK I need to do two things, and the core of my question is, are these the right things, or is there a better way. Thing the first: All event handlers, those functions that will be called any time a redisplay is needed, need to be written at a high level and then passed into the function that actually constructs the widget to begin with. For instance: drawStatData :: DrawingArea -> MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO () createStatView :: (DrawingArea -> IO ()) -> IO VBox createUI :: MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO HBox createUI storeMVar field = do graphs <- createStatView (\area -> drawStatData area storeMVar field) hbox <- hBoxNew False 10 boxPackStart hbox graphs PackNatural 0 return hbox In this case, createStatView builds up a VBox that contains a DrawingArea to graph the data and potentially other widgets. It attaches drawStatData to the realize and exposeEvent events for the DrawingArea. I would do something similar for the TreeView, but I am not completely sure what since I have not yet done it and what I am thinking of would involve replacing the TreeModel every time the TreeView needs to be updated. My alternative to the above would be... drawStatData :: DrawingArea -> MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO () createStatView :: IO (VBox, DrawingArea) ... but in this case, I would arrange createUI like so: createUI :: MVar Core.ST -> (Core.ST -> SetRepWorkout.WorkoutStore) -> IO HBox createUI storeMVar field = do (graphbox, graph) <- createStatView (\area -> drawStatData area storeMVar field) hbox <- hBoxNew False 10 boxPackStart hbox graphs PackNatural 0 on graph realize (drawStatData graph storeMVar field) on graph exposeEvent (do liftIO $ drawStatData graph storeMVar field return ()) return hbox I'm not sure which is better, but that does lead me to... Thing the second: it will be necessary for me to rig up an event system so that various events can send signals all the way to my widgets. I'm going to need a mediator of some kind to pass events around and to translate application-semantic events to the actual events that my widgets respond to. Is it better for me to pass my addressable widgets up the call stack to the level where the mediator lives, or to pass the mediator down the call stack and have the widgets register directly with it? So, in summary, my two questions: 1) pass widgets up the call stack to a global mediator, or pass the global mediator down and have the widgets register themselves to it? 2) pass my redraw functions to the builders and have the builders attach the redraw functions to the constructed widgets, or pass the constructed widgets back and have a higher level attach the redraw functions (and potentially link some widgets together)? Okay, and... 3) Books or wikis about GUI application architecture, preferably coherent architectures where people aren't arguing about minute details? The application in its current form (displays data but does not write data or allow for much interaction) is available at https://bitbucket.org/savannidgerinel/fitness . You can run the application by going to the root directory and typing runhaskell -isrc src/Main.hs data/ or... cabal build dist/build/fitness/fitness data/ You may need to install libraries, but cabal should tell you which ones.

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• Attaching two objects and changing their world matrices accordingly

  - by A-Type

  I'm having a hard time wrapping my head around the transformations required to bind two objects together in either a two-way or one-way relationship. I will need to implement both types. For the first case, I want to be able to 'couple' two ships together in space. The ships have different mass, of course. Forces applied to either ship will use combined mass and moment of inertia to calculate and move both ships. The trick is, being sure that the point at which they are coupled remains the same, and they don't move at all relative to each other. The second case is similar: I want a ship to be able to enter the atmosphere of a planet and move relative to the planet. The planet will be orbiting the sun, which is fixed at 0,0,0. Essentially, when the ship is sitting still outside of the atmosphere, the planet will move past it on its course-- but when the ship is sitting still inside the atmosphere, it moves and rotates with the planet, so that it is always relative to the horizon. Essentially, the vertices which make up the ship are now transformed just like the ones that make up the planet, except that the ship can move itself around relative to the planet. I get the feeling I can implement both of these with the same code. Essentially, I am thinking of giving each object (which I call Fixtures) a list of "slave" Fixtures onto which that Fixture's world matrix is imposed. So, this would be the planet imposing its world on any contained ships. In the case of coupling, I would simply make each ship a slave of the other, somehow. Obviously I can't just multiply the ship's world matrix by the planet's, or each ship by the others. What I'd like some help with is what calculations to make in order to get a nice, seamless relative world to the other object. I was thinking maybe I could just multiply the world of the slave by the inverse of the master, but then when you couple two ships you would lose all that world data. So, perhaps I need an intermediate "world" which is the absolute world, but use a secondary "final world" to actually transform the objects?

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• Am I deluding myself? Business analyst transition to programmer

  - by Ryan

  Current job: Working as the lead business analyst for a Big 4 firm, leading a team of developers and testers working on a large scale re-platforming project (4 onshore dev, 4 offshore devs, several onshore/offshore testers). Also work in a similar capacity on other smaller scale projects. Extent of my role: Gathering/writing out requirements, creating functional specifications, designing the UI (basically mapping out all front-end aspects of the system), working closely with devs to communicate/clarify requirements and come up with solutions when we hit roadblocks, writing test cases (and doing much of the testing), working with senior management and key stakeholders, managing beta testers, creating user guides and leading training sessions, providing key technical support. I also write quite a few macros in Excel using VBA (several of my macros are now used across the entire firm, so there are maybe around 1000 people using them) and use SQL on a daily basis, both on the SQL compact files the program relies on, our SQL Server data and any Access databases I create. The developers feel that I am quite good in this role because I understand a lot about programming, inherent system limitations, structure of the databases, etc so it's easier for me to communicate ideas and come up with suggestions when we face problems. What really interests me is developing software. I do a fair amount of programming in VBA and have been wanting to learn C# for awhile (the dev team uses C# - I review code occasionally for my own sake but have not had any practical experience using it). I'm interested in not just the business process but also the technical side of things, so the traditional BA role doesn't really whet my appetite for the kind of stuff I want to do. Right now I have a few small projects that managers have given me and I'm finding new ways to do them (like building custom Access applications), so there's a bit here and there to keep me interested. My question is this: what I would like to do is create custom Excel or Access applications for small businesses as a freelance business (working as a one-man shop; maybe having an occasional contractor depending on a project's complexity). This would obviously start out as a part-time venture while I have a day job, but eventually become a full-time job. Am I deluding myself to thinking I can go from BA/part-time VBA programmer to making a full-time go of a freelance business (where I would be starting out just writing custom Excel/Access apps in VBA)? Or is this type of thing not usually attempted until someone gains years of full-time programming experience? And is there even a market for these types of applications amongst small businesses (and maybe medium-sized) businesses?

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• Sync Google Calendar with SharePoint Calendar

  - by dataintegration

  The ADO.NET Providers for Google and SharePoint make it easy to retrieve and update data in both Google's web services and SharePoint. This article shows how the SQL interface to data makes it easy to build applications that need to move data from one source to another. The application described here is a demo Windows application that synchronizes calendar events between Google and SharePoint, but the RSSBus Providers can be used to achieve integrations on both the .NET and the Java platforms, including more sophisticated features like full automation. Getting the Events Step 1: Google accounts can have several calendars. Obtain a list of a user's Google Calendars by issuing a query to the Calendars table. For example: SELECT * FROM Calendars. Step 2: In order to get a list of the events from a given Google Calendar, issue a query to the CalendarEvents table while specifying the CalendarId from the Calendars table. The resulting events can be further filtered by using the StartDateTime or EndDateTime columns. For example: SELECT * FROM CalendarEvents WHERE (CalendarId = '[email protected]') AND (StartDateTime >= '1/1/2012') AND (StartDateTime <= '2/1/2012') Step 3: SharePoint stores data in Lists. There are various types of lists, e.g., document lists and calendar lists. A SharePoint account can have several lists of the same type. To find all the calendar lists in SharePoint, use the ListLists stored procedure and inspect the BaseTemplate column. Step 4: The SharePoint data provider models each SharPoint list as a table. Get the events in a particular calendar by querying the table with the same name as the list. The events may be filtered further by specifying the EventDate or EndDate columns. For example: SELECT * FROM Calendar WHERE (EventDate >= '1/1/2012') AND (EventDate <= '2/1/2012') Synchronizing the Events Synchronizing the events is a simple process. Once the events from Google and SharePoint are available they can be compared and synchronized based on user preference. The sample application does this based on user input, but it is easy to create one that does the synchronization automatically. The INSERT, UPDATE, and DELETE statements available in both data providers makes it easy to create, update, or delete events as needed. Pre-Built Demo Application The executable for the demo application can be downloaded here. Note that this demo is built using BETA builds of the ADO.NET Provider for Google V2 and ADO.NET Provider for SharePoint V2, and will expire in 2013. Source Code You can download the full source of the demo application here. You will need the Google ADO.NET Data Provider V2 and the SharePoint ADO.NET Data Provider V2, which can be obtained here.

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• Fixing a NoClassDefFoundError

  - by Chris Okyen

  I have some code: package ftc; import java.util.Scanner; public class Fer_To_Cel { public static void main(String[] argv) { // Scanner object to get the temp in degrees Farenheit Scanner keyboard = new Scanner(System.in); boolean isInt = true; // temporarily put as true in case the user enters a valid int the first time int degreesF = 0; // initialy set to 0 do { try { // Input the temperature text. System.out.print("\nPlease enter a temperature (integer number, no fractional part) in degrees Farenheit: "); degreesF = Integer.parseInt(keyboard.next()); // Get user input and Assign the far. temperature variable, which is casted from String to int. } // Let the user know in a user friendly notice that the value entered wasnt an int ( give int value range ) , and then give error log catch(java.lang.Exception e) { System.out.println("Sorry but you entered a non-int value ( needs to be between ( including ) -2,147,483,648 and 2,147,483,647 ).. \n"); e.printStackTrace(); isInt = false; } } while(!isInt); System.out.println(""); // print a new line. final int degreesC = (5*(degreesF-32)/9); // convert the degrees from F to C and store the resulting expression in degreesC // Print out a newline, then print what X degrees F is in Celcius. System.out.println("\n" + degreesF + " degrees Farenheit is " + degreesC + " degrees Celcius"); } } And The following error: C:\Program Files\Java\jdk1.7.0_06\bin>java Fer_To_Cel Exception in thread "main" java.lang.NoClassDefFoundError: Fer_To_Cel (wrong name: ftc/Fer_To_Cel) at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:791) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:14 at java.net.URLClassLoader.defineClass(URLClassLoader.java:449) at java.net.URLClassLoader.access$100(URLClassLoader.java:71) at java.net.URLClassLoader$1.run(URLClassLoader.java:361) at java.net.URLClassLoader$1.run(URLClassLoader.java:355) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:354) at java.lang.ClassLoader.loadClass(ClassLoader.java:423) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308) at java.lang.ClassLoader.loadClass(ClassLoader.java:356) at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:480) The code compiled without compile errors, but presented errors during execution. Which leads me to two questions. I know Errors can be termed Compiler, Runtime and Logic Errors, but the NoClassDefFoundError inherits java.lang.LinkageError. Does that make it a Linker error, being niether of the three types of errors I listed, If I am right this is the answer. For someone else who obtains the singular .java file and compiles it, would this be the only way to solve this problem? Or can I (should I ) do/have done something to fix this problem? Basically, based on a basis of programming, is this a fault of me as the writer? Could this be done once on, my half and be distributed and not needed be done again?

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• Which programming language to get into?

  - by user602479

  I'm ending my third term in a few weeks so I have some spare time coming up. I'd like to spend it seriously digging into programming. My problem: I'm not sure which language to begin with. Just to be clear, I don't want to start a language-y-compared-to-language-z discussion. There are a some other issues that play a major role. In my 5th term I'm going to be participating in a major practical course which will include either Java or C programming. It will take a lot of time and energy, as I found out while talking to a few students who passed the final exams (only 15% pass on their first try). Which practical course I will take is randomly decided. My skills so far are the absolute basics of Java and C programming. I know the different data types and how to handle them, objects, pointers, thread programming, etc. All of that is on a very low level, though. My question now is, what language should I start seriously practicing? Java: I did my first GUIs with this language. I'm familiar with Eclipse but I need a project to work on (which I don't have) to really keep me pushing. Besides that, I don't think it would help me if I have to do C in a year. C: As with Java, I can't think of a personal project to keep me working and keep me interested in programming. If I get assigned to Java in a year, this wouldn't give me any advantages either, would it? (No objects, etc.) Objective-C: I recently came up with this idea. I have a Mac; I'm not really familiar with Xcode but I have one or two personal projects I'd like to work on. Further, I would be working with objects (as in Java) and C language constructs which would both be great for this practical course in a year. What do you think I should begin with? Should I just stick to Java and hope for the best, force myself through C or start (nearly) completely from the beginning with Objective C? Maybe you folks could give me some good advice that would stop me from switching from one language to the next?

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• Mutable Records in F#

  - by MarkPearl

  I’m loving my expert F# book – today I thought I would give a post on using mutable records as covered in Chapter 4 of Expert F#. So as they explain the simplest mutable data structures in F# are mutable records. The whole concept of things by default being immutable is a new one for me from my C# background. Anyhow… lets look at some C# code first. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace MutableRecords { public class DiscreteEventCounter { public int Total { get; set; } public int Positive { get; set; } public string Name { get; private set; } public DiscreteEventCounter(string name) { Name = name; } } class Program { private static void recordEvent(DiscreteEventCounter s, bool isPositive) { s.Total += 1; if (isPositive) s.Positive += 1; } private static void reportStatus (DiscreteEventCounter s) { Console.WriteLine("We have {0} {1} out of {2}", s.Positive, s.Name, s.Total); } static void Main(string[] args) { var longCounter = new DiscreteEventCounter("My Discrete Counter"); recordEvent(longCounter, true); recordEvent(longCounter, true); reportStatus(longCounter); Console.ReadLine(); } } } Quite simple, we have a class that has a few values. We instantiate an instance of the class and perform increments etc on the instance. Now lets look at an equivalent F# sample. namespace EncapsulationNS module Module1 = open System type DiscreteEventCounter = { mutable Total : int mutable Positive : int Name : string } let recordEvent (s: DiscreteEventCounter) isPositive = s.Total <- s.Total+1 if isPositive then s.Positive <- s.Positive+1 let reportStatus (s: DiscreteEventCounter) = printfn "We have %d %s out of %d" s.Positive s.Name s.Total let newCounter nm = { Total = 0; Positive = 0; Name = nm } // // Using it... // let longCounter = newCounter "My Discrete Counter" recordEvent longCounter (true) recordEvent longCounter (true) reportStatus longCounter System.Console.ReadLine() Notice in the type declaration of the DiscreteEventCounter we had to explicitly declare that the total and positive value holders were mutable. And that’s it – a very simple example of mutable types.

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• CS, SE, HCI, Information Science, Please recommendation for further education of the former performing art manager seeking career in IT industries? [on hold]

  - by Baek Seungjoo

  IT specialists there J Thank you very much for your collective efforts here, and I got huge help reading your professional comments and advices on each questions I have searched so far! This time, I would like to ask for your practical advices or recommendation on what I am struggling on at this moment. I am currently seeking higher education for my career transition from performing art manager and director to “IT software and/or service development and management specialist”. However, as this field is quite new to me, and there are lots of different work positions, I have no idea which grad major I better pursue in order to get qualification. Of course I know this question could sounds wired as it is kind of personal choice. But my lack of understanding on how IT software companies work in general, your practical and experience-based advice will be great help to me, who spent more than two months of self-research on net. OK. Before my question, here is my plan and history, which are quite different from those currently in IT industry I think… 1) Target Firstly, get career transition into IT service or products companies and get experiences. Eventually, pursue IT entrepreneurship in combination with my arts and cultural production and business expertise. 2) Background Career: performing arts director and manager in theatre-based scale opera and musical Art education in youth BA in literature and Chinese studies (Art & Humanities) MA in Cultural & Creative Industries (Art & Humanities) – dissertation with focus on digital prosumption and the lived experience of the prosumer. (a qualitative research on the agents in the digital world) 2) Personally Huge interest in IT hardware and software, and their trend. Skills to build up, repair, tune PCs -of course this is no more than personal hobby, but shows my interests in this field. 4) Problem Encounter a question “So, what do you think you can contribute practically in this position”. This question turn me down everytime I go through job interviews, and I decided more education in the relevant area. Here are my questions. 1) In terms of work positions in IT software companies, I wonder if I can put the comparison of what “Artists” is to “Arts Manager or Director” is what “Developer” is to “Product Manager”. (Of course, this stereotypical division of Artist-Art Manager is out of sense because the domain overlaps to some extent, and is blurring at least in my field, and they are in different contexts, but just speaking easily.) Normally, artist comes with special arts educations, and they live in their own world of artistic inspiration and creation, and they feel alive in practice and on stages. Meanwhile, from the point of staging and managing productions, the role of art manager is critical as well. Our role cares how the production appeals to the audience in effective way, how to make profit and future sustainable management through that, how to set up future strategy in consideration of the external conditions such as political and social circumstances, audience trend and level, other production trends from on-going and historical perspectives, how and what the production make voice to the society from political, economic, humanitarian stances. So, we need keen eyes on economic, political, and societal environment, have to understand human-being and their desires, must know how to make presentation and attract investors, must have sense in managing and fighting over the limited financial resource, how to extend networking and so on. It is common that the two agents create productions in collaboration (normally not in that ideal way but in conflict and fight though J ). So, we need to know each other’s expertise to some extent, for better production. What are the work positions in IT software industries equivalent to the role of “art manager” in performing arts? From my view, considering developers come with special education in the world of computer science, software engineering, or others (self-education sometimes), and they express themselves with the arts of coding, computer languages on the black screen, and make sort of their artistic production online to the audience, I guess there might be someone who collaborate with developers in creating, managing, and launching IT services or products. 2) Which education among CS, SE, HCI, Information Science, is needed for those seeking such work position? Especially for person like me. (At this moment, Information Science has the highest possibility to get in, since I lack Calculus and Math in undergrad educaiton. But please let me know irrespective of this concern, I think there are ways to back it up if CS or SE education needed in my case) 3) Which field between Information Science and HCI can be more practical background regarding job hungting? And which of them have more demands in job market? AS I checked, HCI is more close to CS than IS in its focus of study area. Thank you very much for your patience reading such a long inquiry, and I appreciate to your efforts in advance. Have a nice day in this beautiful summer.

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• What to "CRM" in San Francisco? CRM Highlights for OpenWorld '12

  - by Richard Lefebvre

  There is plenty to SEE for CRM during OpenWorld in San Francisco, September 30 - October 4! Here are some of the sessions in the CRM Track that you might want to consider attending for products you currently own or might consider for the future. I think you'll agree, there is quite a bit of investment going on across Oracle CRM. Please use OpenWorld Schedule Builder or check the OpenWorld Content Catalog for all of the session details and any time or location changes. Tip: Pre-enrolled session registrants via Schedule Builder are allowed into the session rooms before anyone else, so Schedule Builder will guarantee you a seat. Many of the sessions below will likely be at capacity. General Session: Oracle Fusion CRM—Improving Sales Effectiveness, Efficiency, and Ease of Use (Session ID: GEN9674) - Oct 2, 11:45 AM - 12:45 PM. Anthony Lye, Senior VP, Oracle leads this general session focused on Oracle Fusion CRM. Oracle Fusion CRM optimizes territories, combines quota management and incentive compensation, integrates sales and marketing, and cleanses and enriches data—all within a single application platform. Oracle Fusion can be configured, changed, and extended at runtime by end users, business managers, IT, and developers. Oracle Fusion CRM can be used from the Web, from a smartphone, from Microsoft Outlook, or from an iPad. Deloitte, sponsor of the CRM Track, will also present key concepts on CRM implementations. Oracle Fusion Customer Relationship Management: Overview/Strategy/Customer Experiences/Roadmap (CON9407) - Oct 1, 3:15PM - 4:15PM. In this session, learn how Oracle Fusion CRM enables companies to create better sales plans, generate more quality leads, and achieve higher win rates and find out why customers are adopting Oracle Fusion CRM. Gain a deeper understanding of the unique capabilities only Oracle Fusion CRM provides, and learn how Oracle’s commitment to CRM innovation is driving a wide range of future enhancements. Oracle RightNow CX Cloud Service Vision and Roadmap (CON9764) - Oct 1, 10:45 AM - 11:45 AM. Oracle RightNow CX Cloud Service combines Web, social, and contact center experiences for a unified, cross-channel service solution in the cloud, enabling organizations to increase sales and adoption, build trust, strengthen relationships, and reduce costs and effort. Come to this session to hear from Oracle experts about where the product is going and how Oracle is committed to accelerating the pace of innovation and value to its customers. Siebel CRM Overview, Strategy, and Roadmap (CON9700) - Oct 1, 12:15PM - 1:15PM. The world’s most complete CRM solution, Oracle’s Siebel CRM helps organizations differentiate their businesses. Come to this session to learn about the Siebel product roadmap and how Oracle is committed to accelerating the pace of innovation and value for its customers on this platform. Additionally, the session covers how Siebel customers can leverage many Oracle assets such as Oracle WebCenter Sites; InQuira, RightNow, and ATG/Endeca applications, and Oracle Policy Automation in conjunction with their current Siebel investments. Oracle Fusion Social CRM Strategy and Roadmap: Future of Collaboration and Social Engagement (CON9750) - Oct 4, 11:15 AM - 12:15 PM. Social is changing the customer experience! Come find out how Oracle can help you know your customers better, encourage brand affinity, and improve collaboration within your ecosystem. This session reviews Oracle’s social media solution and shows how you can discover hidden insights buried in your enterprise and social data. Also learn how Oracle Social Network revolutionizes how enterprise users work, collaborate, and share to achieve successful outcomes. Oracle CRM On Demand Strategy and Roadmap (CON9727) - Oct 1, 10:45AM - 11:45AM. Oracle CRM On Demand is a powerful cloud-based customer relationship management solution. Come to this session to learn directly from Oracle experts about future product plans and hear how Oracle is committed to accelerating the pace of innovation and value to its customers. Knowledge Management Roadmap and Strategy (CON9776) - Oct 1, 12:15PM - 1:15PM. Learn how to harness the knowledge created as a natural byproduct of day-to-day interactions to lower costs and improve customer experience by delivering the right answer at the right time across channels. This session includes an overview of Oracle’s product roadmap and vision for knowledge management for both the Oracle RightNow and Oracle Knowledge (formerly InQuira) product families. Oracle Policy Automation Roadmap: Supercharging the Customer Experience (CON9655) - Oct 1, 12:15PM - 1:15PM. Oracle Policy Automation delivers rapid customer value by streamlining the capture, analysis, and deployment of policies across every facet of the customer experience. This session discusses recent Oracle Policy Automation enhancements for policy analytics; the latest Oracle Policy Automation Connector for Siebel; and planned new capabilities, including availability with the Oracle RightNow product line. There is much more, so stay tuned for more highlights or check out the Content Catalog and search for your areas of interest. 

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• Alternatives to multiple inheritance for my architecture (NPCs in a Realtime Strategy game)?

  - by Brettetete

  Coding isn't that hard actually. The hard part is to write code that makes sense, is readable and understandable. So I want to get a better developer and create some solid architecture. So I want to do create an architecture for NPCs in a video-game. It is a Realtime Strategy game like Starcraft, Age of Empires, Command & Conquers, etc etc.. So I'll have different kinds of NPCs. A NPC can have one to many abilities (methods) of these: Build(), Farm() and Attack(). Examples: Worker can Build() and Farm() Warrior can Attack() Citizen can Build(), Farm() and Attack() Fisherman can Farm() and Attack() I hope everything is clear so far. So now I do have my NPC Types and their abilities. But lets come to the technical / programmatical aspect. What would be a good programmatic architecture for my different kinds of NPCs? Okay I could have a base class. Actually I think this is a good way to stick with the DRY principle. So I can have methods like WalkTo(x,y) in my base class since every NPC will be able to move. But now lets come to the real problem. Where do I implement my abilities? (remember: Build(), Farm() and Attack()) Since the abilities will consists of the same logic it would be annoying / break DRY principle to implement them for each NPC (Worker,Warrior, ..). Okay I could implement the abilities within the base class. This would require some kind of logic that verifies if a NPC can use ability X. IsBuilder, CanBuild, .. I think it is clear what I want to express. But I don't feel very well with this idea. This sounds like a bloated base class with too much functionality. I do use C# as programming language. So multiple inheritance isn't an opinion here. Means: Having extra base classes like Fisherman : Farmer, Attacker won't work.

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• Synergy - easy share of keyboard and mouse between multiple computers

  Did you ever have the urge to share one set of keyboard and mouse between multiple machines? If so, please read on... Using multiple machines Honestly, as a software craftsman it is my daily business to run multiple machines - either physical or virtual - to be able to solve my customers' requirements. Recent hardware equipment allows this very easily. For laptops it's a no-brainer to attach a second or even a third screen in order to extend your native display. This works quite handy and in my case I used to attached two additional screens - one via HD15 connector, the other via HDMI. But... as it's a laptop and therefore a mobile unit there are slight restrictions. Detaching and re-attaching all cables when changing locations is one of them but hardware limitations, too. After all, it's a laptop and not a workstation. I guess, that anyone working in IT (or ICT) has more than one machine at their workplace or their home office and at least I find it quite annoying to have multiple sets of keyboard and mouse conquering my remaining space on my desk. Despite the ugly looks of all those cables and whatsoever 'chaos of distraction' I prefer a more clean solution and working environment. This allows me to actually focus on my work and tasks to do rather than to worry about choosing the right combination of keyboard/mouse. My current workplace is a patch work of various pieces of hardware (approx. 2-3 years): DIY desktop on Ubuntu 12.04 64-bit, Core2 Duo (E7400, 2.8GHz), 4GB RAM, 2x 250GB HDD, nVidia GPU 512MB Dell Inspiron 1525 on Windows 8 64-bit, 4GB RAM, 200GB HDD HP Compaq 6720s on Windows Vista 32-bit, Core2 Duo (T5670, 1.8GHz), 2GB RAM, 160GB HDD Mac mini on Mac OS X 10.7, Core i5 (2.3 GHz), 2GB RAM, 500GB HDD I know... Not the latest and greatest but a decent combination to work with. New system(s) is/are already on the shopping list but I live in the 'wrong' country to buy computer hardware. So, the next trip abroad will provide me with some new stuff. Using multiple operating systems The list of hardware above already names different operating systems, and actually I have only one preference: Linux. But still my job as a software craftsman for Visual FoxPro and .NET development requires other OSes, too. Not a big deal, it's just like this. Additionally to those physical machines, there are a bunch of virtual machines around. Most of them running either Windows XP or Windows 7. Since years I have the practice that each development for one customer is isolated into its own virtual machine and environment. This keeps it clean and version-safe. But as you can easily imagine with that setup there are a couple of constraints referring to keyboard and mouse. Usually, those systems require their own pieces of hardware attached. As stated, I don't like clutter on my desk's surface, so a cross-platform solution has to come in here. In the past, I tried it with various applications, hardware or network protocols like X11, RDP, NX, TeamViewer, RAdmin, KVM switch, etc. but the problem in this case is that they either allow you to remotely connect to the other system or exclusively 'bind' your peripherals to the active system. Not optimal after all. Synergy to the rescue Quote from their website: "Synergy lets you easily share your mouse and keyboard between multiple computers on your desk, and it's Free and Open Source. Just move your mouse off the edge of one computer's screen on to another. You can even share all of your clipboards. All you need is a network connection. Synergy is cross-platform (works on Windows, Mac OS X and Linux)." Yep, that's it! All I need for my setup here... Actually, I couldn't believe it myself that I didn't stumble over synergy earlier but 'Get over it' and there we go. And despite the fact that it is Open Source, no, it's also for free. Donations for the developers are very welcome and recently they introduced Synergy Premium. A possibility to buy so-called premium votes that can be used to put more weight / importance on specific issues or bugs that you would like the developers to look into. Installation and configuration Simply download the installation packages for your systems of choice, run the installer and enter some minor information about your network setup. I chose my desktop machine for the role of the Synergy server and configured my screen setup as follows: The screen setup allows you currently to build or connect up to 15 machines. The number of screens can be higher as those machine might have multiple screens physically attached. Synergy takes this into the overall calculations and simply works as expected. I tried it for fun with a second monitor each connected to both laptops to have a total number of 6 active screens. No flaws after all - stunning! All the other machines are configured as clients like so: Side note: The screenshot was taken on Windows 8 and pasted via clipboard into Gimp running on Ubuntu. Resume Synergy is now definitely in my box of tools for my daily work, and amongst the first pieces of software I install after the operating system. It just simplifies my life and cleans my desk. Never again without Synergy!Now, only waiting for an Android version to integrate my Galaxy Tab 10.1, too. ;-) Please, check out that superb product and enjoy sharing one keyboard, one mouse and one clipboard between your various machines and operating systems.

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• Pirates, Treasure Chests and Architectural Mapping

  Pirate 1: Why do pirates create treasure maps? Pirate 2: I do not know.Pirate 1: So they can find their gold. Yes, that was a bad joke, but it does illustrate a point. Pirates are known for drawing treasure maps to their most prized possession. These documents detail the decisions pirates made in order to hide and find their chests of gold. The map allows them to trace the steps they took originally to hide their treasure so that they may return. As software engineers, programmers, and architects we need to treat software implementations much like our treasure chest. Why is software like a treasure chest? It cost money, time,  and resources to develop (Usually) It can make or save money, time, and resources (Hopefully) If we operate under the assumption that software is like a treasure chest then wouldn’t make sense to document the steps, rationale, concerns, and decisions about how it was designed? Pirates are notorious for documenting where they hide their treasure.  Shouldn’t we as creators of software do the same? By documenting our design decisions and rationale behind them will help others be able to understand and maintain implemented systems. This can only be done if the design decisions are correctly mapped to its corresponding implementation. This allows for architectural decisions to be traced from the conceptual model, architectural design and finally to the implementation. Mapping gives software professional a method to trace the reason why specific areas of code were developed verses other options. Just like the pirates we need to able to trace our steps from the start of a project to its implementation,  so that we will understand why specific choices were chosen. The traceability of a software implementation that actually maps back to its originating design decisions is invaluable for ensuring that architectural drifting and erosion does not take place. The drifting and erosion is prevented by allowing others to understand the rational of why an implementation was created in a specific manor or methodology The process of mapping distinct design concerns/decisions to the location of its implemented is called traceability. In this context traceability is defined as method for connecting distinctive software artifacts. This process allows architectural design models and decisions to be directly connected with its physical implementation. The process of mapping architectural design concerns to a software implementation can be very complex. However, most design decision can be placed in  a few generalized categories. Commonly Mapped Design Decisions Design Rationale Components and Connectors Interfaces Behaviors/Properties Design rational is one of the hardest categories to map directly to an implementation. Typically this rational is mapped or document in code via comments. These comments consist of general design decisions and reasoning because they do not directly refer to a specific part of an application. They typically focus more on the higher level concerns. Components and connectors can directly be mapped to architectural concerns. Typically concerns subdivide an application in to distinct functional areas. These functional areas then can map directly back to their originating concerns.Interfaces can be mapped back to design concerns in one of two ways. Interfaces that pertain to specific function definitions can be directly mapped back to its originating concern(s). However, more complicated interfaces require additional analysis to ensure that the proper mappings are created. Depending on the complexity some Behaviors\Properties can be translated directly into a generic implementation structure that is ready for business logic. In addition, some behaviors can be translated directly in to an actual implementation depending on the complexity and architectural tools used. Mapping design concerns to an implementation is a lot of work to maintain, but is doable. In order to ensure that concerns are mapped correctly and that an implementation correctly reflects its design concerns then one of two standard approaches are usually used. All Changes Come From ArchitectureBy forcing all application changes to come through the architectural model prior to implementation then the existing mappings will be used to locate where in the implementation changes need to occur. Allow Changes From Implementation Or Architecture By allowing changes to come from the implementation and/or the architecture then the other area must be kept in sync. This methodology is more complex compared to the previous approach.  One reason to justify the added complexity for an application is due to the fact that this approach tends to detect and prevent architectural drift and erosion. Additionally, this approach is usually maintained via software because of the complexity. Reference:Taylor, R. N., Medvidovic, N., & Dashofy, E. M. (2009). Software architecture: Foundations, theory, and practice Hoboken, NJ: John Wiley & Sons  

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