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• Transactional Messaging in the Windows Azure Service Bus

  - by Alan Smith

  Introduction I’m currently working on broadening the content in the Windows Azure Service Bus Developer Guide. One of the features I have been looking at over the past week is the support for transactional messaging. When using the direct programming model and the WCF interface some, but not all, messaging operations can participate in transactions. This allows developers to improve the reliability of messaging systems. There are some limitations in the transactional model, transactions can only include one top level messaging entity (such as a queue or topic, subscriptions are no top level entities), and transactions cannot include other systems, such as databases. As the transaction model is currently not well documented I have had to figure out how things work through experimentation, with some help from the development team to confirm any questions I had. Hopefully I’ve got the content mostly correct, I will update the content in the e-book if I find any errors or improvements that can be made (any feedback would be very welcome). I’ve not had a chance to look into the code for transactions and asynchronous operations, maybe that would make a nice challenge lab for my Windows Azure Service Bus course. Transactional Messaging Messaging entities in the Windows Azure Service Bus provide support for participation in transactions. This allows developers to perform several messaging operations within a transactional scope, and ensure that all the actions are committed or, if there is a failure, none of the actions are committed. There are a number of scenarios where the use of transactions can increase the reliability of messaging systems. Using TransactionScope In .NET the TransactionScope class can be used to perform a series of actions in a transaction. The using declaration is typically used de define the scope of the transaction. Any transactional operations that are contained within the scope can be committed by calling the Complete method. If the Complete method is not called, any transactional methods in the scope will not commit.   // Create a transactional scope. using (TransactionScope scope = new TransactionScope()) {     // Do something.       // Do something else.       // Commit the transaction.     scope.Complete(); }     In order for methods to participate in the transaction, they must provide support for transactional operations. Database and message queue operations typically provide support for transactions. Transactions in Brokered Messaging Transaction support in Service Bus Brokered Messaging allows message operations to be performed within a transactional scope; however there are some limitations around what operations can be performed within the transaction. In the current release, only one top level messaging entity, such as a queue or topic can participate in a transaction, and the transaction cannot include any other transaction resource managers, making transactions spanning a messaging entity and a database not possible. When sending messages, the send operations can participate in a transaction allowing multiple messages to be sent within a transactional scope. This allows for “all or nothing” delivery of a series of messages to a single queue or topic. When receiving messages, messages that are received in the peek-lock receive mode can be completed, deadlettered or deferred within a transactional scope. In the current release the Abandon method will not participate in a transaction. The same restrictions of only one top level messaging entity applies here, so the Complete method can be called transitionally on messages received from the same queue, or messages received from one or more subscriptions in the same topic. Sending Multiple Messages in a Transaction A transactional scope can be used to send multiple messages to a queue or topic. This will ensure that all the messages will be enqueued or, if the transaction fails to commit, no messages will be enqueued.     An example of the code used to send 10 messages to a queue as a single transaction from a console application is shown below.   QueueClient queueClient = messagingFactory.CreateQueueClient(Queue1);   Console.Write("Sending");   // Create a transaction scope. using (TransactionScope scope = new TransactionScope()) {     for (int i = 0; i < 10; i++)     {         // Send a message         BrokeredMessage msg = new BrokeredMessage("Message: " + i);         queueClient.Send(msg);         Console.Write(".");     }     Console.WriteLine("Done!");     Console.WriteLine();       // Should we commit the transaction?     Console.WriteLine("Commit send 10 messages? (yes or no)");     string reply = Console.ReadLine();     if (reply.ToLower().Equals("yes"))     {         // Commit the transaction.         scope.Complete();     } } Console.WriteLine(); messagingFactory.Close();     The transaction scope is used to wrap the sending of 10 messages. Once the messages have been sent the user has the option to either commit the transaction or abandon the transaction. If the user enters “yes”, the Complete method is called on the scope, which will commit the transaction and result in the messages being enqueued. If the user enters anything other than “yes”, the transaction will not commit, and the messages will not be enqueued. Receiving Multiple Messages in a Transaction The receiving of multiple messages is another scenario where the use of transactions can improve reliability. When receiving a group of messages that are related together, maybe in the same message session, it is possible to receive the messages in the peek-lock receive mode, and then complete, defer, or deadletter the messages in one transaction. (In the current version of Service Bus, abandon is not transactional.)   The following code shows how this can be achieved. using (TransactionScope scope = new TransactionScope()) {       while (true)     {         // Receive a message.         BrokeredMessage msg = q1Client.Receive(TimeSpan.FromSeconds(1));         if (msg != null)         {             // Wrote message body and complete message.             string text = msg.GetBody<string>();             Console.WriteLine("Received: " + text);             msg.Complete();         }         else         {             break;         }     }     Console.WriteLine();       // Should we commit?     Console.WriteLine("Commit receive? (yes or no)");     string reply = Console.ReadLine();     if (reply.ToLower().Equals("yes"))     {         // Commit the transaction.         scope.Complete();     }     Console.WriteLine(); }     Note that if there are a large number of messages to be received, there will be a chance that the transaction may time out before it can be committed. It is possible to specify a longer timeout when the transaction is created, but It may be better to receive and commit smaller amounts of messages within the transaction. It is also possible to complete, defer, or deadletter messages received from more than one subscription, as long as all the subscriptions are contained in the same topic. As subscriptions are not top level messaging entities this scenarios will work. The following code shows how this can be achieved. try {     using (TransactionScope scope = new TransactionScope())     {         // Receive one message from each subscription.         BrokeredMessage msg1 = subscriptionClient1.Receive();         BrokeredMessage msg2 = subscriptionClient2.Receive();           // Complete the message receives.         msg1.Complete();         msg2.Complete();           Console.WriteLine("Msg1: " + msg1.GetBody<string>());         Console.WriteLine("Msg2: " + msg2.GetBody<string>());           // Commit the transaction.         scope.Complete();     } } catch (Exception ex) {     Console.WriteLine(ex.Message); }     Unsupported Scenarios The restriction of only one top level messaging entity being able to participate in a transaction makes some useful scenarios unsupported. As the Windows Azure Service Bus is under continuous development and new releases are expected to be frequent it is possible that this restriction may not be present in future releases. The first is the scenario where messages are to be routed to two different systems. The following code attempts to do this.   try {     // Create a transaction scope.     using (TransactionScope scope = new TransactionScope())     {         BrokeredMessage msg1 = new BrokeredMessage("Message1");         BrokeredMessage msg2 = new BrokeredMessage("Message2");           // Send a message to Queue1         Console.WriteLine("Sending Message1");         queue1Client.Send(msg1);           // Send a message to Queue2         Console.WriteLine("Sending Message2");         queue2Client.Send(msg2);           // Commit the transaction.         Console.WriteLine("Committing transaction...");         scope.Complete();     } } catch (Exception ex) {     Console.WriteLine(ex.Message); }     The results of running the code are shown below. When attempting to send a message to the second queue the following exception is thrown: No active Transaction was found for ID '35ad2495-ee8a-4956-bbad-eb4fedf4a96e:1'. The Transaction may have timed out or attempted to span multiple top-level entities such as Queue or Topic. The server Transaction timeout is: 00:01:00..TrackingId:947b8c4b-7754-4044-b91b-4a959c3f9192_3_3,TimeStamp:3/29/2012 7:47:32 AM.   Another scenario where transactional support could be useful is when forwarding messages from one queue to another queue. This would also involve more than one top level messaging entity, and is therefore not supported.   Another scenario that developers may wish to implement is performing transactions across messaging entities and other transactional systems, such as an on-premise database. In the current release this is not supported.   Workarounds for Unsupported Scenarios There are some techniques that developers can use to work around the one top level entity limitation of transactions. When sending two messages to two systems, topics and subscriptions can be used. If the same message is to be sent to two destinations then the subscriptions would have the default subscriptions, and the client would only send one message. If two different messages are to be sent, then filters on the subscriptions can route the messages to the appropriate destination. The client can then send the two messages to the topic in the same transaction.   In scenarios where a message needs to be received and then forwarded to another system within the same transaction topics and subscriptions can also be used. A message can be received from a subscription, and then sent to a topic within the same transaction. As a topic is a top level messaging entity, and a subscription is not, this scenario will work.

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• Queued Loadtest to remove Concurrency issues using Shared Data Service in OpenScript

  - by stefan.thieme(at)oracle.com

  Queued Processing to remove Concurrency issues in Loadtest ScriptsSome scripts act on information returned by the server, e.g. act on first item in the returned list of pending tasks/actions. This may lead to concurrency issues if the virtual users simulated in a load test scenario are not synchronized in some way.As the load test cases should be carried out in a comparable and straight forward manner simply cancel a transaction in case a collision occurs is clearly not an option. In case you increase the number of virtual users this approach would lead to a high number of requests for the early steps in your transaction (e.g. login, retrieve list of action points, assign an action point to the virtual user) but later steps would be rarely visited successfully or at all, depending on the application logic.A way to tackle this problem is to enqueue the virtual users in a Shared Data Service queue. Only the first virtual user in this queue will be allowed to carry out the critical steps (retrieve list of action points, assign an action point to the virtual user) in your transaction at any one time.Once a virtual user has passed the critical path it will dequeue himself from the head of the queue and continue with his actions. This does theoretically allow virtual users to run in parallel all steps of the transaction which are not part of the critical path.In practice it has been seen this is rarely the case, though it does not allow adding more than N users to perform a transaction without causing delays due to virtual users waiting in the queue. N being the time of the total transaction divided by the sum of the time of all critical steps in this transaction.While this problem can be circumvented by allowing multiple queues to act on individual segments of the list of actions, e.g. per country filter, ends with 0..9 filter, etc.This would require additional handling of these additional queues of slots for the virtual users at the head of the queue in order to maintain the mutually exclusive access to the first element in the list returned by the server at any one time of the load test. Such an improved handling of multiple queues and/or multiple slots is above the subject of this paper.Shared Data Services Pre-RequisitesStart WebLogic Server to host Shared Data ServicesYou will have to make sure that your WebLogic server is installed and started. Shared Data Services may not work if you installed only the minimal installation package for OpenScript. If however you installed the default package including OLT and OTM, you may follow the instructions below to start and verify WebLogic installation.To start the WebLogic Server deployed underneath of Oracle Load Testing and/or Oracle Test Manager you can go to your Start menu, Oracle Application Testing Suite and select the Restart Oracle Application Testing Suite Application Service entry from the Tools submenu.To verify the service has been started you can run the Microsoft Management Console for Services by Selecting Run from the Start Menu and entering services.msc. Look for the entry that reads Oracle Application Testing Suite Application Service, once it has changed it status from Starting to Started you can proceed to verify the login. Please note that this may take several minutes, I would say up to 10 minutes depending on the strength of your CPU horse-power.Verify WebLogic Server user credentialsYou will have to make sure that your WebLogic Server is installed and started. Next open the Oracle WebLogic Server Adminstration Console on http://localhost:8088/console.It may take a while until the application is deployed and started. It may display the following until the Administration Console has been deployed on the fly.Afterwards you can login using the username oats and the password that you selected during install time for your Application Testing Suite administrative purposes.This will bring up the Home page of you WebLogic Server. You have actually verified that you are able to login with these credentials already. However if you want to check the details, navigate to Security Realms, myrealm, Users and Groups tab.Here you could add users to your WebLogic Server which could be used in the later steps. Details on the Groups required for such a custom user to work are exceeding this quick overview and have to be selected with the WebLogic Server Adminstration Guide in mind.Shared Data Services pre-requisites for Load testingOpenScript Preferences have to be set to enable Encryption and provide a default Shared Data Service Connection for Playback.These are pre-requisites you want to use for load testing with Shared Data Services.Please note that the usage of the Connection Parameters (individual directive in the script) for Shared Data Services did not playback reliably in the current version 9.20.0370 of Oracle Load Testing (OLT) and encryption of credentials still seemed to be mandatory as well.General Encryption settingsSelect OpenScript Preferences from the View menu and navigate to the General, Encryption entry in the tree on the left. Select the Encrypt script data option from the list and enter the same password that you used for securing your WebLogic Server Administration Console.Enable global shared data access credentialsSelect OpenScript Preferences from the View menu and navigate to the Playback, Shared Data entry in the tree on the left. Enable the global shared data access credentials and enter the Address, User name and Password determined for your WebLogic Server to host Shared Data Services.Please note, that you may want to replace the localhost in Address with the hosts realname in case you plan to run load tests with Loadtest Agents running on remote systems.Queued Processing of TransactionsEnable Shared Data Services Module in Script PropertiesThe Shared Data Services Module has to be enabled for each Script that wants to employ the Shared Data Service Queue functionality in OpenScript. It can be enabled under the Script menu selecting Script Properties. On the Script Properties Dialog select the Modules section and check Shared Data to enable Shared Data Service Module for your script. Checking the Shared Data Services option will effectively add a line to your script code that adds the sharedData ScriptService to your script class of IteratingVUserScript.@ScriptService oracle.oats.scripting.modules.sharedData.api.SharedDataService sharedData;Record your scriptRecord your script as usual and then add the following things for Queue handling in the Initialize code block, before the first step and after the last step of your critical path and in the Finalize code block.The java code to be added at individual locations is explained in the following sections in full detail.Create a Shared Data Queue in InitializeTo create a Shared Data Queue go to the Java view of your script and enter the following statements to the initialize() code block.info("Create queueA with life time of 120 minutes");sharedData.createQueue("queueA", 120);This will create an instantiation of the Shared Data Queue object named queueA which is maintained for upto 120 minutes.If you want to use the code for multiple scripts, make sure to use a different queue name for each one here and in the subsequent steps. You may even consider to use a dynamic queueName based on filters of your result list being concurrently accessed.Prepare a unique id for each IterationIn order to keep track of individual virtual users in our queue we need to create a unique identifier from the virtual user id and the used username right after retrieving the next record from our databank file.getDatabank("Usernames").getNextDatabankRecord();getVariables().set("usernameValue1","VU_{{@vuid}}_{{@iterationnum}}_{{db.Usernames.Username}}_{{@timestamp}}_{{@random(10000)}}");String usernameValue = getVariables().get("usernameValue1");info("Now running virtual user " + usernameValue);As you can see from the above code block, we have set the OpenScript variable usernameValue1 to VU_{{@vuid}}_{{@iterationnum}}_{{db.Usernames.Username}}_{{@timestamp}}_{{@random(10000)}} which is a concatenation of the virtual user id and the iterationnumber for general uniqueness; as well as the username from our databank, the timestamp and a random number for making it further unique and ease spotting of errors.Not all of these fields are actually required to make it really unique, but adding the queue name may also be considered to help troubleshoot multiple queues.The value is then retrieved with the getVariables.get() method call and assigned to the usernameValue String used throughout the script.Please note that moving the getDatabank("Usernames").getNextDatabankRecord(); call to the initialize block was later considered to remove concurrency of multiple virtual users running with the same userid and therefor accessing the same "My Inbox" in step 6. This will effectively give each virtual user a userid from the databank file. Make sure you have enough userids to remove this second hurdle.Enqueue and attend Queue before Critical PathTo maintain the right order of virtual users being allowed into the critical path of the transaction the following pseudo step has to be added in front of the first critical step. In the case of this example this is right in front of the step where we retrieve the list of actions from which we select the first to be assigned to us.beginStep("[0] Waiting in the Queue", 0);{info("Enqueued virtual user " + usernameValue + " at the end of queueA");sharedData.offerLast("queueA", usernameValue);info("Wait until the user is the first in queueA");String queueValue1 = null;do {// we wait for at least 0.7 seconds before we check the head of the// queue. This is the time it takes one user to move through the// critical path, i.e. pass steps [5] Enter country and [6] Assign// to meThread.sleep(700);queueValue1 = (String) sharedData.peekFirst("queueA");info("The first user in queueA is currently: '" + queueValue1 + "' " + queueValue1.getClass() + " length " + queueValue1.length() );info("The current user is '"+ usernameValue + "' " + usernameValue.getClass() + " length " + usernameValue.length() + ": indexOf " + usernameValue.indexOf(queueValue1) + " equals " + usernameValue.equals(queueValue1) );} while ( queueValue1.indexOf(usernameValue) < 0 );info("Now the user is the first in queueA");}endStep();This will enqueue the username to the tail of our Queue. It will will wait for at least 700 milliseconds, the time it takes for one user to exit the critical path and then compare the head of our queue with it's username. This last step will be repeated while the two are not equal (indexOf less than zero). If they are equal the indexOf will yield a value of zero or larger and we will perform the critical steps.Dequeue after Critical PathAfter the virtual user has left the critical path and complete its last step the following code block needs to dequeue the virtual user. In the case of our example this is right after the action has been actually assigned to the virtual user. This will allow the next virtual user to retrieve the list of actions still available and in turn let him make his selection/assignment.info("Get and remove the current user from the head of queueA");String pollValue1 = (String) sharedData.pollFirst("queueA");The current user is removed from the head of the queue. The next one will now be able to match his username against the head of the queue.Clear and Destroy Queue for FinishWhen the script has completed, it should clear and destroy the queue. This code block can be put in the finish block of your script and/or in a separate script in order to clear and remove the queue in case you have spotted an error or want to reset the queue for some reason.info("Clear queueA");sharedData.clearQueue("queueA");info("Destroy queueA");sharedData.destroyQueue("queueA");The users waiting in queueA are cleared and the queue is destroyed. If you have scripts still executing they will be caught in a loop.I found it better to maintain a separate Reset Queue script which contained only the following code in the initialize() block. I use to call this script to make sure the queue is cleared in between multiple Loadtest runs. This script could also even be added as the first in a larger scenario, which would execute it only once at very start of the Loadtest and make sure the queues do not contain any stale entries.info("Create queueA with life time of 120 minutes");sharedData.createQueue("queueA", 120);info("Clear queueA");sharedData.clearQueue("queueA");This will create a Shared Data Queue instance of queueA and clear all entries from this queue.Monitoring QueueWhile creating the scripts it was useful to monitor the contents, i.e. the current first user in the Queue. The following code block will make sure the Shared Data Queue is accessible in the initialize() block.info("Create queueA with life time of 120 minutes");sharedData.createQueue("queueA", 120);In the run() block the following code will continuously monitor the first element of the Queue and write an informational message with the current username Value to the Result window.info("Monitor the first users in queueA");String queueValue1 = null;do {queueValue1 = (String) sharedData.peekFirst("queueA");if (queueValue1 != null)info("The first user in queueA is currently: '" + queueValue1 + "' " + queueValue1.getClass() + " length " + queueValue1.length() );} while ( true );This script can be run from OpenScript parallel to a loadtest performed by the Oracle Load Test.However it is not recommend to run this in a production loadtest as the performance impact is unknown. Accessing the Queue's head with the peekFirst() method has been reported with about 2 seconds response time by both OpenScript and OTL. It is advised to log a Service Request to see if this could be lowered in future releases of Application Testing Suite, as the pollFirst() and even offerLast() writing to the tail of the Queue usually returned after an average 0.1 seconds.Debugging QueueWhile debugging the scripts the following was useful to remove single entries from its head, i.e. the current first user in the Queue. The following code block will make sure the Shared Data Queue is accessible in the initialize() block.info("Create queueA with life time of 120 minutes");sharedData.createQueue("queueA", 120);In the run() block the following code will remove the first element of the Queue and write an informational message with the current username Value to the Result window.info("Get and remove the current user from the head of queueA");String pollValue1 = (String) sharedData.pollFirst("queueA");info("The first user in queueA was currently: '" + pollValue1 + "' " + pollValue1.getClass() + " length " + pollValue1.length() );ReferencesOracle Functional Testing OpenScript User's Guide Version 9.20 [E15488-05]Chapter 17 Using the Shared Data Modulehttp://download.oracle.com/otn/nt/apptesting/oats-docs-9.21.0030.zipOracle Fusion Middleware Oracle WebLogic Server Administration Console Online Help 11g Release 1 (10.3.4) [E13952-04]Administration Console Online Help - Manage users and groupshttp://download.oracle.com/docs/cd/E17904_01/apirefs.1111/e13952/taskhelp/security/ManageUsersAndGroups.htm

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• Should we enforce code style in our large codebase?

  - by eighttrackmind

  By "code style" I mean 2 things: Style, eg. // bad if(foo){ ... } // good if (foo) { ... } Conventions and idiomaticity, where two ways of writing the same thing are functionally equivalent, but one is more idiomatic. eg. // bad if (fooLib.equals(a, b)) { ... } // good if (a == b) { ... } I think it makes sense to use an auto-formatter to enforce #1 automatically. So my question is specifically about #2. I like to break things down into pros and cons, here's what I've come up with so far: Pros: Used by many large codebases (eg. Google, jQuery) Helps make it a bit easier to work on new areas of the codebase Helps make code more portable (this is not necessarily true) Code style is automatic once you get used to it Makes it easier to fast-decline pull requests Cons: Takes engineers’ and code reviewers’ time away from more important things (like developing features) Code should ideally be rewritten every 2-3 years anyway, so it’s more important to focus on getting the architecture right, and achieving high test coverage Adds strain to code reviews (eg. “don’t do it this way, I like this other way better”) Even if I’ve been using a code style for a while, I still sometime have to pause and think about how to write a line better Having an enforced, uniform code style makes it hard to experiment with potentially better styles Maintaining a style guide takes a lot of incremental effort Engineers rarely read through the style guide. More often, it's cited in code reviews And as a secondary question: we also have many smaller repositories - should the same code style be enforced there?

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• MVC Automatic Menu

  - by Nuri Halperin

  An ex-colleague of mine used to call his SQL script generator "Super-Scriptmatic 2000". It impressed our then boss little, but was fun to say and use. We called every batch job and script "something 2000" from that day on. I'm tempted to call this one Menu-Matic 2000, except it's waaaay past 2000. Oh well. The problem: I'm developing a bunch of stuff in MVC. There's no PM to generate mounds of requirements and there's no Ux Architect to create wireframe. During development, things change. Specifically, actions get renamed, moved from controller x to y etc. Well, as the site grows, it becomes a major pain to keep a static menu up to date, because the links change. The HtmlHelper doesn't live up to it's name and provides little help. How do I keep this growing list of pesky little forgotten actions reigned in? The general plan is: Decorate every action you want as a menu item with a custom attribute Reflect out all menu items into a structure at load time Render the menu using as CSS  friendly <ul><li> HTML. The MvcMenuItemAttribute decorates an action, designating it to be included as a menu item: [AttributeUsage(AttributeTargets.Method, AllowMultiple = true)] public class MvcMenuItemAttribute : Attribute {   public string MenuText { get; set; }   public int Order { get; set; }   public string ParentLink { get; set; }   internal string Controller { get; set; }   internal string Action { get; set; }     #region ctor   public MvcMenuItemAttribute(string menuText) : this(menuText, 0) { } public MvcMenuItemAttribute(string menuText, int order) { MenuText = menuText; Order = order; }       internal string Link { get { return string.Format("/{0}/{1}", Controller, this.Action); } }   internal MvcMenuItemAttribute ParentItem { get; set; } #endregion } The MenuText allows overriding the text displayed on the menu. The Order allows the items to be ordered. The ParentLink allows you to make this item a child of another menu item. An example action could then be decorated thusly: [MvcMenuItem("Tracks", Order = 20, ParentLink = "/Session/Index")] . All pretty straightforward methinks. The challenge with menu hierarchy becomes fairly apparent when you try to render a menu and highlight the "current" item or render a breadcrumb control. Both encounter an  ambiguity if you allow a data source to have more than one menu item with the same URL link. The issue is that there is no great way to tell which link a person click. Using referring URL will fail if a user bookmarked the page. Using some extra query string to disambiguate duplicate URLs essentially changes the links, and also ads a chance of collision with other query parameters. Besides, that smells. The stock ASP.Net sitemap provider simply disallows duplicate URLS. I decided not to, and simply pick the first one encountered as the "current". Although it doesn't solve the issue completely – one might say they wanted the second of the 2 links to be "current"- it allows one to include a link twice (home->deals and products->deals etc), and the logic of deciding "current" is easy enough to explain to the customer. Now that we got that out of the way, let's build the menu data structure: public static List<MvcMenuItemAttribute> ListMenuItems(Assembly assembly) { var result = new List<MvcMenuItemAttribute>(); foreach (var type in assembly.GetTypes()) { if (!type.IsSubclassOf(typeof(Controller))) { continue; } foreach (var method in type.GetMethods()) { var items = method.GetCustomAttributes(typeof(MvcMenuItemAttribute), false) as MvcMenuItemAttribute[]; if (items == null) { continue; } foreach (var item in items) { if (String.IsNullOrEmpty(item.Controller)) { item.Controller = type.Name.Substring(0, type.Name.Length - "Controller".Length); } if (String.IsNullOrEmpty(item.Action)) { item.Action = method.Name; } result.Add(item); } } } return result.OrderBy(i => i.Order).ToList(); } Using reflection, the ListMenuItems method takes an assembly (you will hand it your MVC web assembly) and generates a list of menu items. It digs up all the types, and for each one that is an MVC Controller, digs up the methods. Methods decorated with the MvcMenuItemAttribute get plucked and added to the output list. Again, pretty simple. To make the structure hierarchical, a LINQ expression matches up all the items to their parent: public static void RegisterMenuItems(List<MvcMenuItemAttribute> items) { _MenuItems = items; _MenuItems.ForEach(i => i.ParentItem = items.FirstOrDefault(p => String.Equals(p.Link, i.ParentLink, StringComparison.InvariantCultureIgnoreCase))); } The _MenuItems is simply an internal list to keep things around for later rendering. Finally, to package the menu building for easy consumption: public static void RegisterMenuItems(Type mvcApplicationType) { RegisterMenuItems(ListMenuItems(Assembly.GetAssembly(mvcApplicationType))); } To bring this puppy home, a call in Global.asax.cs Application_Start() registers the menu. Notice the ugliness of reflection is tucked away from the innocent developer. All they have to do is call the RegisterMenuItems() and pass in the type of the application. When you use the new project template, global.asax declares a class public class MvcApplication : HttpApplication and that is why the Register call passes in that type. protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes);   MvcMenu.RegisterMenuItems(typeof(MvcApplication)); }   What else is left to do? Oh, right, render! public static void ShowMenu(this TextWriter output) { var writer = new HtmlTextWriter(output);   renderHierarchy(writer, _MenuItems, null); }   public static void ShowBreadCrumb(this TextWriter output, Uri currentUri) { var writer = new HtmlTextWriter(output); string currentLink = "/" + currentUri.GetComponents(UriComponents.Path, UriFormat.Unescaped);   var menuItem = _MenuItems.FirstOrDefault(m => m.Link.Equals(currentLink, StringComparison.CurrentCultureIgnoreCase)); if (menuItem != null) { renderBreadCrumb(writer, _MenuItems, menuItem); } }   private static void renderBreadCrumb(HtmlTextWriter writer, List<MvcMenuItemAttribute> menuItems, MvcMenuItemAttribute current) { if (current == null) { return; } var parent = current.ParentItem; renderBreadCrumb(writer, menuItems, parent); writer.Write(current.MenuText); writer.Write(" / ");   }     static void renderHierarchy(HtmlTextWriter writer, List<MvcMenuItemAttribute> hierarchy, MvcMenuItemAttribute root) { if (!hierarchy.Any(i => i.ParentItem == root)) return;   writer.RenderBeginTag(HtmlTextWriterTag.Ul); foreach (var current in hierarchy.Where(element => element.ParentItem == root).OrderBy(i => i.Order)) { if (ItemFilter == null || ItemFilter(current)) {   writer.RenderBeginTag(HtmlTextWriterTag.Li); writer.AddAttribute(HtmlTextWriterAttribute.Href, current.Link); writer.AddAttribute(HtmlTextWriterAttribute.Alt, current.MenuText); writer.RenderBeginTag(HtmlTextWriterTag.A); writer.WriteEncodedText(current.MenuText); writer.RenderEndTag(); // link renderHierarchy(writer, hierarchy, current); writer.RenderEndTag(); // li } } writer.RenderEndTag(); // ul } The ShowMenu method renders the menu out to the provided TextWriter. In previous posts I've discussed my partiality to using well debugged, time test HtmlTextWriter to render HTML rather than writing out angled brackets by hand. In addition, writing out using the actual writer on the actual stream rather than generating string and byte intermediaries (yes, StringBuilder being no exception) disturbs me. To carry out the rendering of an hierarchical menu, the recursive renderHierarchy() is used. You may notice that an ItemFilter is called before rendering each item. I figured that at some point one might want to exclude certain items from the menu based on security role or context or something. That delegate is the hook for such future feature. To carry out rendering of a breadcrumb recursion is used again, this time simply to unwind the parent hierarchy from the leaf node, then rendering on the return from the recursion rather than as we go along deeper. I guess I was stuck in LISP that day.. recursion is fun though.   Now all that is left is some usage! Open your Site.Master or wherever you'd like to place a menu or breadcrumb, and plant one of these calls: <% MvcMenu.ShowBreadCrumb(this.Writer, Request.Url); %> to show a breadcrumb trail (notice lack of "=" after <% and the semicolon). <% MvcMenu.ShowMenu(Writer); %> to show the menu.   As mentioned before, the HTML output is nested <UL> <LI> tags, which should make it easy to style using abundant CSS to produce anything from static horizontal or vertical to dynamic drop-downs.   This has been quite a fun little implementation and I was pleased that the code size remained low. The main crux was figuring out how to pass parent information from the attribute to the hierarchy builder because attributes have restricted parameter types. Once I settled on that implementation, the rest falls into place quite easily.

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• C#: String Concatenation vs Format vs StringBuilder

  - by James Michael Hare

  I was looking through my groups’ C# coding standards the other day and there were a couple of legacy items in there that caught my eye.  They had been passed down from committee to committee so many times that no one even thought to second guess and try them for a long time.  It’s yet another example of how micro-optimizations can often get the best of us and cause us to write code that is not as maintainable as it could be for the sake of squeezing an extra ounce of performance out of our software. So the two standards in question were these, in paraphrase: Prefer StringBuilder or string.Format() to string concatenation. Prefer string.Equals() with case-insensitive option to string.ToUpper().Equals(). Now some of you may already know what my results are going to show, as these items have been compared before on many blogs, but I think it’s always worth repeating and trying these yourself.  So let’s dig in. The first test was a pretty standard one.  When concattenating strings, what is the best choice: StringBuilder, string concattenation, or string.Format()? So before we being I read in a number of iterations from the console and a length of each string to generate.  Then I generate that many random strings of the given length and an array to hold the results.  Why am I so keen to keep the results?  Because I want to be able to snapshot the memory and don’t want garbage collection to collect the strings, hence the array to keep hold of them.  I also didn’t want the random strings to be part of the allocation, so I pre-allocate them and the array up front before the snapshot.  So in the code snippets below: num – Number of iterations. strings – Array of randomly generated strings. results – Array to hold the results of the concatenation tests. timer – A System.Diagnostics.Stopwatch() instance to time code execution. start – Beginning memory size. stop – Ending memory size. after – Memory size after final GC. So first, let’s look at the concatenation loop: 1: // build num strings using concattenation. 2: for (int i = 0; i < num; i++) 3: { 4: results[i] = "This is test #" + i + " with a result of " + strings[i]; 5: } Pretty standard, right?  Next for string.Format(): 1: // build strings using string.Format() 2: for (int i = 0; i < num; i++) 3: { 4: results[i] = string.Format("This is test #{0} with a result of {1}", i, strings[i]); 5: }   Finally, StringBuilder: 1: // build strings using StringBuilder 2: for (int i = 0; i < num; i++) 3: { 4: var builder = new StringBuilder(); 5: builder.Append("This is test #"); 6: builder.Append(i); 7: builder.Append(" with a result of "); 8: builder.Append(strings[i]); 9: results[i] = builder.ToString(); 10: } So I take each of these loops, and time them by using a block like this: 1: // get the total amount of memory used, true tells it to run GC first. 2: start = System.GC.GetTotalMemory(true); 3:  4: // restart the timer 5: timer.Reset(); 6: timer.Start(); 7:  8: // *** code to time and measure goes here. *** 9:  10: // get the current amount of memory, stop the timer, then get memory after GC. 11: stop = System.GC.GetTotalMemory(false); 12: timer.Stop(); 13: other = System.GC.GetTotalMemory(true); So let’s look at what happens when I run each of these blocks through the timer and memory check at 500,000 iterations: 1: Operator + - Time: 547, Memory: 56104540/55595960 - 500000 2: string.Format() - Time: 749, Memory: 57295812/55595960 - 500000 3: StringBuilder - Time: 608, Memory: 55312888/55595960 – 500000   Egad!  string.Format brings up the rear and + triumphs, well, at least in terms of speed.  The concat burns more memory than StringBuilder but less than string.Format().  This shows two main things: StringBuilder is not always the panacea many think it is. The difference between any of the three is miniscule! The second point is extremely important!  You will often here people who will grasp at results and say, “look, operator + is 10% faster than StringBuilder so always use StringBuilder.”  Statements like this are a disservice and often misleading.  For example, if I had a good guess at what the size of the string would be, I could have preallocated my StringBuffer like so:   1: for (int i = 0; i < num; i++) 2: { 3: // pre-declare StringBuilder to have 100 char buffer. 4: var builder = new StringBuilder(100); 5: builder.Append("This is test #"); 6: builder.Append(i); 7: builder.Append(" with a result of "); 8: builder.Append(strings[i]); 9: results[i] = builder.ToString(); 10: }   Now let’s look at the times: 1: Operator + - Time: 551, Memory: 56104412/55595960 - 500000 2: string.Format() - Time: 753, Memory: 57296484/55595960 - 500000 3: StringBuilder - Time: 525, Memory: 59779156/55595960 - 500000   Whoa!  All of the sudden StringBuilder is back on top again!  But notice, it takes more memory now.  This makes perfect sense if you examine the IL behind the scenes.  Whenever you do a string concat (+) in your code, it examines the lengths of the arguments and creates a StringBuilder behind the scenes of the appropriate size for you. But even IF we know the approximate size of our StringBuilder, look how much less readable it is!  That’s why I feel you should always take into account both readability and performance.  After all, consider all these timings are over 500,000 iterations.   That’s at best  0.0004 ms difference per call which is neglidgable at best.  The key is to pick the best tool for the job.  What do I mean?  Consider these awesome words of wisdom: Concatenate (+) is best at concatenating.  StringBuilder is best when you need to building. Format is best at formatting. Totally Earth-shattering, right!  But if you consider it carefully, it actually has a lot of beauty in it’s simplicity.  Remember, there is no magic bullet.  If one of these always beat the others we’d only have one and not three choices. The fact is, the concattenation operator (+) has been optimized for speed and looks the cleanest for joining together a known set of strings in the simplest manner possible. StringBuilder, on the other hand, excels when you need to build a string of inderterminant length.  Use it in those times when you are looping till you hit a stop condition and building a result and it won’t steer you wrong. String.Format seems to be the looser from the stats, but consider which of these is more readable.  Yes, ignore the fact that you could do this with ToString() on a DateTime.  1: // build a date via concatenation 2: var date1 = (month < 10 ? string.Empty : "0") + month + '/' 3: + (day < 10 ? string.Empty : "0") + '/' + year; 4:  5: // build a date via string builder 6: var builder = new StringBuilder(10); 7: if (month < 10) builder.Append('0'); 8: builder.Append(month); 9: builder.Append('/'); 10: if (day < 10) builder.Append('0'); 11: builder.Append(day); 12: builder.Append('/'); 13: builder.Append(year); 14: var date2 = builder.ToString(); 15:  16: // build a date via string.Format 17: var date3 = string.Format("{0:00}/{1:00}/{2:0000}", month, day, year); 18:  So the strength in string.Format is that it makes constructing a formatted string easy to read.  Yes, it’s slower, but look at how much more elegant it is to do zero-padding and anything else string.Format does. So my lesson is, don’t look for the silver bullet!  Choose the best tool.  Micro-optimization almost always bites you in the end because you’re sacrificing readability for performance, which is almost exactly the wrong choice 90% of the time. I love the rules of optimization.  They’ve been stated before in many forms, but here’s how I always remember them: For Beginners: Do not optimize. For Experts: Do not optimize yet. It’s so true.  Most of the time on today’s modern hardware, a micro-second optimization at the sake of readability will net you nothing because it won’t be your bottleneck.  Code for readability, choose the best tool for the job which will usually be the most readable and maintainable as well.  Then, and only then, if you need that extra performance boost after profiling your code and exhausting all other options… then you can start to think about optimizing.

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• LINQ: Enhancing Distinct With The PredicateEqualityComparer

  - by Paulo Morgado

  Today I was writing a LINQ query and I needed to select distinct values based on a comparison criteria. Fortunately, LINQ’s Distinct method allows an equality comparer to be supplied, but, unfortunately, sometimes, this means having to write custom equality comparer. Because I was going to need more than one equality comparer for this set of tools I was building, I decided to build a generic equality comparer that would just take a custom predicate. Something like this: public class PredicateEqualityComparer<T> : EqualityComparer<T> { private Func<T, T, bool> predicate; public PredicateEqualityComparer(Func<T, T, bool> predicate) : base() { this.predicate = predicate; } public override bool Equals(T x, T y) { if (x != null) { return ((y != null) && this.predicate(x, y)); } if (y != null) { return false; } return true; } public override int GetHashCode(T obj) { if (obj == null) { return 0; } return obj.GetHashCode(); } } Now I can write code like this: .Distinct(new PredicateEqualityComparer<Item>((x, y) => x.Field == y.Field)) But I felt that I’d lost all conciseness and expressiveness of LINQ and it doesn’t support anonymous types. So I came up with another Distinct extension method: public static IEnumerable<TSource> Distinct<TSource>(this IEnumerable<TSource> source, Func<TSource, TSource, bool> predicate) { return source.Distinct(new PredicateEqualityComparer<TSource>(predicate)); } And the query is now written like this: .Distinct((x, y) => x.Field == y.Field) Looks a lot better, doesn’t it?

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• A Simple Approach For Presenting With Code Samples

  - by Jesse Taber

  Originally posted on: http://geekswithblogs.net/GruffCode/archive/2013/07/31/a-simple-approach-for-presenting-with-code-samples.aspxI’ve been getting ready for a presentation and have been struggling a bit with the best way to show and execute code samples. I don’t present often (hardly ever), but when I do I like the presentation to have a lot of succinct and executable code snippets to help illustrate the points that I’m making. Depending on what the presentation is about, I might just want to build an entire sample application that I would run during the presentation. In other cases, however, building a full-blown application might not really be the best way to present the code. The presentation I’m working on now is for an open source utility library for dealing with dates and times. I could have probably cooked up a sample app for accepting date and time input and then contrived ways in which it could put the library through its paces, but I had trouble coming up with one app that would illustrate all of the various features of the library that I wanted to highlight. I finally decided that what I really needed was an approach that met the following criteria: Simple: I didn’t want the user interface or overall architecture of a sample application to serve as a distraction from the demonstration of the syntax of the library that the presentation is about. I want to be able to present small bits of code that are focused on accomplishing a single task. Several of these examples will look similar, and that’s OK. I want each sample to “stand on its own” and not rely much on external classes or methods (other than the library that is being presented, of course). “Debuggable” (not really a word, I know): I want to be able to easily run the sample with the debugger attached in Visual Studio should I want to step through any bits of code and show what certain values might be at run time. As far as I know this rules out something like LinqPad, though using LinqPad to present code samples like this is actually a very interesting idea that I might explore another time. Flexible and Selectable: I’m going to have lots of code samples to show, and I want to be able to just package them all up into a single project or module and have an easy way to just run the sample that I want on-demand. Since I’m presenting on a .NET framework library, one of the simplest ways in which I could execute some code samples would be to just create a Console application and use Console.WriteLine to output the pertinent info at run time. This gives me a “no frills” harness from which to run my code samples, and I just hit ‘F5’ to run it with the debugger. This satisfies numbers 1 and 2 from my list of criteria above, but item 3 is a little harder. By default, just running a console application is going to execute the ‘main’ method, and then terminate the program after all code is executed. If I want to have several different code samples and run them one at a time, it would be cumbersome to keep swapping the code I want in and out of the ‘main’ method of the console application. What I really want is an easy way to keep the console app running throughout the whole presentation and just have it run the samples I want when I want. I could setup a simple Windows Forms or WPF desktop application with buttons for the different samples, but then I’m getting away from my first criteria of keeping things as simple as possible. Infinite Loops To The Rescue I found a way to have a simple console application satisfy all three of my requirements above, and it involves using an infinite loop and some Console.ReadLine calls that will give the user an opportunity to break out and exit the program. (All programs that need to run until they are closed explicitly (or crash!) likely use similar constructs behind the scenes. Create a new Windows Forms project, look in the ‘Program.cs’ that gets generated, and then check out the docs for the Application.Run method that it calls.). Here’s how the main method might look: 1: static void Main(string[] args) 2: { 3: do 4: { 5: Console.Write("Enter command or 'exit' to quit: > "); 6: var command = Console.ReadLine(); 7: if ((command ?? string.Empty).Equals("exit", StringComparison.OrdinalIgnoreCase)) 8: { 9: Console.WriteLine("Quitting."); 10: break; 11: } 12: 13: } while (true); 14: } The idea here is the app prompts me for the command I want to run, or I can type in ‘exit’ to break out of the loop and let the application close. The only trick now is to create a set of commands that map to each of the code samples that I’m going to want to run. Each sample is already encapsulated in a single public method in a separate class, so I could just write a big switch statement or create a hashtable/dictionary that maps command text to an Action that will invoke the proper method, but why re-invent the wheel? CLAP For Your Own Presentation I’ve blogged about the CLAP library before, and it turns out that it’s a great fit for satisfying criteria #3 from my list above. CLAP lets you decorate methods in a class with an attribute and then easily invoke those methods from within a console application. CLAP was designed to take the arguments passed into the console app from the command line and parse them to determine which method to run and what arguments to pass to that method, but there’s no reason you can’t re-purpose it to accept command input from within the infinite loop defined above and invoke the corresponding method. Here’s how you might define a couple of different methods to contain two different code samples that you want to run during your presentation: 1: public static class CodeSamples 2: { 3: [Verb(Aliases="one")] 4: public static void SampleOne() 5: { 6: Console.WriteLine("This is sample 1"); 7: } 8:   9: [Verb(Aliases="two")] 10: public static void SampleTwo() 11: { 12: Console.WriteLine("This is sample 2"); 13: } 14: } A couple of things to note about the sample above: I’m using static methods. You don’t actually need to use static methods with CLAP, but the syntax ends up being a bit simpler and static methods happen to lend themselves well to the “one self-contained method per code sample” approach that I want to use. The methods are decorated with a ‘Verb’ attribute. This tells CLAP that they are eligible targets for commands. The “Aliases” argument lets me give them short and easy-to-remember aliases that can be used to invoke them. By default, CLAP just uses the full method name as the command name, but with aliases you can simply the usage a bit. I’m not using any parameters. CLAP’s main feature is its ability to parse out arguments from a command line invocation of a console application and automatically pass them in as parameters to the target methods. My code samples don’t need parameters ,and honestly having them would complicate giving the presentation, so this is a good thing. You could use this same approach to invoke methods with parameters, but you’d have a couple of things to figure out. When you invoke a .NET application from the command line, Windows will parse the arguments and pass them in as a string array (called ‘args’ in the boilerplate console project Program.cs). The parsing that gets done here is smart enough to deal with things like treating strings in double quotes as one argument, and you’d have to re-create that within your infinite loop if you wanted to use parameters. I plan on either submitting a pull request to CLAP to add this capability or maybe just making a small utility class/extension method to do it and posting that here in the future. So I now have a simple class with static methods to contain my code samples, and an infinite loop in my ‘main’ method that can accept text commands. Wiring this all up together is pretty easy: 1: static void Main(string[] args) 2: { 3: do 4: { 5: try 6: { 7: Console.Write("Enter command or 'exit' to quit: > "); 8: var command = Console.ReadLine(); 9: if ((command ?? string.Empty).Equals("exit", StringComparison.OrdinalIgnoreCase)) 10: { 11: Console.WriteLine("Quitting."); 12: break; 13: } 14:   15: Parser.Run<CodeSamples>(new[] { command }); 16: Console.WriteLine("---------------------------------------------------------"); 17: } 18: catch (Exception ex) 19: { 20: Console.Error.WriteLine("Error: " + ex.Message); 21: } 22:   23: } while (true); 24: } Note that I’m now passing the ‘CodeSamples’ class into the CLAP ‘Parser.Run’ as a type argument. This tells CLAP to inspect that class for methods that might be able to handle the commands passed in. I’m also throwing in a little “----“ style line separator and some basic error handling (because I happen to know that some of the samples are going to throw exceptions for demonstration purposes) and I’m good to go. Now during my presentation I can just have the console application running the whole time with the debugger attached and just type in the alias of the code sample method that I want to run when I want to run it.

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• How to read values from RESX file in ASP.NET using ResXResourceReader

  Here is the method which returns the value for a particular key in a given resource file. Below method assumes resourceFileName is the resource filename and key is the string for which the value has to be retrieved. public static string ReadValueFromResourceFile(String resourceFileName, String key)    {        String _value = String.Empty;        ResXResourceReader _resxReader = new ResXResourceReader(            String.Format("{0}{1}\\{2}",System.AppDomain.CurrentDomain.BaseDirectory.ToString(), StringConstants.ResourceFolderName , resourceFileName));        foreach (DictionaryEntry _item in _resxReader)        {            if (_item.Key.Equals(key))            {                _value = _item.Value.ToString();                break;            }        }        return _value;    } span.fullpost {display:none;}

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• C#/.NET Little Wonders: Tuples and Tuple Factory Methods

  - 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 really help improve your code by making it easier to write and maintain.  This week, we look at the System.Tuple class and the handy factory methods for creating a Tuple by inferring the types. What is a Tuple? The System.Tuple is a class that tends to inspire a reaction in one of two ways: love or hate.  Simply put, a Tuple is a data structure that holds a specific number of items of a specific type in a specific order.  That is, a Tuple<int, string, int> is a tuple that contains exactly three items: an int, followed by a string, followed by an int.  The sequence is important not only to distinguish between two members of the tuple with the same type, but also for comparisons between tuples.  Some people tend to love tuples because they give you a quick way to combine multiple values into one result.  This can be handy for returning more than one value from a method (without using out or ref parameters), or for creating a compound key to a Dictionary, or any other purpose you can think of.  They can be especially handy when passing a series of items into a call that only takes one object parameter, such as passing an argument to a thread's startup routine.  In these cases, you do not need to define a class, simply create a tuple containing the types you wish to return, and you are ready to go? On the other hand, there are some people who see tuples as a crutch in object-oriented design.  They may view the tuple as a very watered down class with very little inherent semantic meaning.  As an example, what if you saw this in a piece of code: 1: var x = new Tuple<int, int>(2, 5); What are the contents of this tuple?  If the tuple isn't named appropriately, and if the contents of each member are not self evident from the type this can be a confusing question.  The people who tend to be against tuples would rather you explicitly code a class to contain the values, such as: 1: public sealed class RetrySettings 2: { 3: public int TimeoutSeconds { get; set; } 4: public int MaxRetries { get; set; } 5: } Here, the meaning of each int in the class is much more clear, but it's a bit more work to create the class and can clutter a solution with extra classes. So, what's the correct way to go?  That's a tough call.  You will have people who will argue quite well for one or the other.  For me, I consider the Tuple to be a tool to make it easy to collect values together easily.  There are times when I just need to combine items for a key or a result, in which case the tuple is short lived and so the meaning isn't easily lost and I feel this is a good compromise.  If the scope of the collection of items, though, is more application-wide I tend to favor creating a full class. Finally, it should be noted that tuples are immutable.  That means they are assigned a value at construction, and that value cannot be changed.  Now, of course if the tuple contains an item of a reference type, this means that the reference is immutable and not the item referred to. Tuples from 1 to N Tuples come in all sizes, you can have as few as one element in your tuple, or as many as you like.  However, since C# generics can't have an infinite generic type parameter list, any items after 7 have to be collapsed into another tuple, as we'll show shortly. So when you declare your tuple from sizes 1 (a 1-tuple or singleton) to 7 (a 7-tuple or septuple), simply include the appropriate number of type arguments: 1: // a singleton tuple of integer 2: Tuple<int> x; 3:  4: // or more 5: Tuple<int, double> y; 6:  7: // up to seven 8: Tuple<int, double, char, double, int, string, uint> z; Anything eight and above, and we have to nest tuples inside of tuples.  The last element of the 8-tuple is the generic type parameter Rest, this is special in that the Tuple checks to make sure at runtime that the type is a Tuple.  This means that a simple 8-tuple must nest a singleton tuple (one of the good uses for a singleton tuple, by the way) for the Rest property. 1: // an 8-tuple 2: Tuple<int, int, int, int, int, double, char, Tuple<string>> t8; 3:  4: // an 9-tuple 5: Tuple<int, int, int, int, double, int, char, Tuple<string, DateTime>> t9; 6:  7: // a 16-tuple 8: Tuple<int, int, int, int, int, int, int, Tuple<int, int, int, int, int, int, int, Tuple<int,int>>> t14; Notice that on the 14-tuple we had to have a nested tuple in the nested tuple.  Since the tuple can only support up to seven items, and then a rest element, that means that if the nested tuple needs more than seven items you must nest in it as well.  Constructing tuples Constructing tuples is just as straightforward as declaring them.  That said, you have two distinct ways to do it.  The first is to construct the tuple explicitly yourself: 1: var t3 = new Tuple<int, string, double>(1, "Hello", 3.1415927); This creates a triple that has an int, string, and double and assigns the values 1, "Hello", and 3.1415927 respectively.  Make sure the order of the arguments supplied matches the order of the types!  Also notice that we can't half-assign a tuple or create a default tuple.  Tuples are immutable (you can't change the values once constructed), so thus you must provide all values at construction time. Another way to easily create tuples is to do it implicitly using the System.Tuple static class's Create() factory methods.  These methods (much like C++'s std::make_pair method) will infer the types from the method call so you don't have to type them in.  This can dramatically reduce the amount of typing required especially for complex tuples! 1: // this 4-tuple is typed Tuple<int, double, string, char> 2: var t4 = Tuple.Create(42, 3.1415927, "Love", 'X'); Notice how much easier it is to use the factory methods and infer the types?  This can cut down on typing quite a bit when constructing tuples.  The Create() factory method can construct from a 1-tuple (singleton) to an 8-tuple (octuple), which of course will be a octuple where the last item is a singleton as we described before in nested tuples. Accessing tuple members Accessing a tuple's members is simplicity itself… mostly.  The properties for accessing up to the first seven items are Item1, Item2, …, Item7.  If you have an octuple or beyond, the final property is Rest which will give you the nested tuple which you can then access in a similar matter.  Once again, keep in mind that these are read-only properties and cannot be changed. 1: // for septuples and below, use the Item properties 2: var t1 = Tuple.Create(42, 3.14); 3:  4: Console.WriteLine("First item is {0} and second is {1}", 5: t1.Item1, t1.Item2); 6:  7: // for octuples and above, use Rest to retrieve nested tuple 8: var t9 = new Tuple<int, int, int, int, int, int, int, 9: Tuple<int, int>>(1,2,3,4,5,6,7,Tuple.Create(8,9)); 10:  11: Console.WriteLine("The 8th item is {0}", t9.Rest.Item1); Tuples are IStructuralComparable and IStructuralEquatable Most of you know about IComparable and IEquatable, what you may not know is that there are two sister interfaces to these that were added in .NET 4.0 to help support tuples.  These IStructuralComparable and IStructuralEquatable make it easy to compare two tuples for equality and ordering.  This is invaluable for sorting, and makes it easy to use tuples as a compound-key to a dictionary (one of my favorite uses)! Why is this so important?  Remember when we said that some folks think tuples are too generic and you should define a custom class?  This is all well and good, but if you want to design a custom class that can automatically order itself based on its members and build a hash code for itself based on its members, it is no longer a trivial task!  Thankfully the tuple does this all for you through the explicit implementations of these interfaces. For equality, two tuples are equal if all elements are equal between the two tuples, that is if t1.Item1 == t2.Item1 and t1.Item2 == t2.Item2, and so on.  For ordering, it's a little more complex in that it compares the two tuples one at a time starting at Item1, and sees which one has a smaller Item1.  If one has a smaller Item1, it is the smaller tuple.  However if both Item1 are the same, it compares Item2 and so on. For example: 1: var t1 = Tuple.Create(1, 3.14, "Hi"); 2: var t2 = Tuple.Create(1, 3.14, "Hi"); 3: var t3 = Tuple.Create(2, 2.72, "Bye"); 4:  5: // true, t1 == t2 because all items are == 6: Console.WriteLine("t1 == t2 : " + t1.Equals(t2)); 7:  8: // false, t1 != t2 because at least one item different 9: Console.WriteLine("t2 == t2 : " + t2.Equals(t3)); The actual implementation of IComparable, IEquatable, IStructuralComparable, and IStructuralEquatable is explicit, so if you want to invoke the methods defined there you'll have to manually cast to the appropriate interface: 1: // true because t1.Item1 < t3.Item1, if had been same would check Item2 and so on 2: Console.WriteLine("t1 < t3 : " + (((IComparable)t1).CompareTo(t3) < 0)); So, as I mentioned, the fact that tuples are automatically equatable and comparable (provided the types you use define equality and comparability as needed) means that we can use tuples for compound keys in hashing and ordering containers like Dictionary and SortedList: 1: var tupleDict = new Dictionary<Tuple<int, double, string>, string>(); 2:  3: tupleDict.Add(t1, "First tuple"); 4: tupleDict.Add(t2, "Second tuple"); 5: tupleDict.Add(t3, "Third tuple"); Because IEquatable defines GetHashCode(), and Tuple's IStructuralEquatable implementation creates this hash code by combining the hash codes of the members, this makes using the tuple as a complex key quite easy!  For example, let's say you are creating account charts for a financial application, and you want to cache those charts in a Dictionary based on the account number and the number of days of chart data (for example, a 1 day chart, 1 week chart, etc): 1: // the account number (string) and number of days (int) are key to get cached chart 2: var chartCache = new Dictionary<Tuple<string, int>, IChart>(); Summary The System.Tuple, like any tool, is best used where it will achieve a greater benefit.  I wouldn't advise overusing them, on objects with a large scope or it can become difficult to maintain.  However, when used properly in a well defined scope they can make your code cleaner and easier to maintain by removing the need for extraneous POCOs and custom property hashing and ordering. They are especially useful in defining compound keys to IDictionary implementations and for returning multiple values from methods, or passing multiple values to a single object parameter. Tweet Technorati Tags: C#,.NET,Tuple,Little Wonders

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• Perpendicularity of a normal and a velocity?

  - by Milo

  I'm trying to fake angular velocity on my vehicle when it hits a wall by getting the dot product of the normal of the edge the car is hitting and the vehicle's velocity: Vector2D normVel = new Vector2D(); normVel.equals(vehicle.getVelocity()); normVel.normalize(); float dot = normVel.dot(outNorm); dot = -dot; vehicle.setAngularVelocity(vehicle.getAngularVelocity() + (dot * vehicle.getVelocity().length() * 0.01f)); outNorm is the normal of the wall. The problem is it only works half the time. It seems no matter what, the car always goes clockwise. If the car should head clockwise: -------------------------------------- / / I want the angular velocity to be positive, otherwise if it needs to go CCW: -------------------------------------- \ \ Then the angular velocity should be negative... What should I change to achieve this? Thanks Hmmm... Im not sure why this is not working... for(int i = 0; i < buildings.size(); ++i) { e = buildings.get(i); ArrayList<Vector2D> colPts = vehicle.getRect().getCollsionPoints(e.getRect()); float dist = OBB2D.collisionResponse(vehicle.getRect(), e.getRect(), outNorm); for(int u = 0; u < colPts.size(); ++u) { Vector2D p = colPts.get(u).subtract(vehicle.getRect().getCenter()); vehicle.setTorque(vehicle.getTorque() + p.cross(outNorm)); }

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• How to read values from RESX file in ASP.NET using ResXResourceReader

  Here is the method which returns the value for a particular key in a given resource file. Below method assumes resourceFileName is the resource filename and key is the string for which the value has to be retrieved. public static string ReadValueFromResourceFile(String resourceFileName, String key)    {        String _value = String.Empty;        ResXResourceReader _resxReader = new ResXResourceReader(            String.Format("{0}{1}\\{2}",System.AppDomain.CurrentDomain.BaseDirectory.ToString(), StringConstants.ResourceFolderName , resourceFileName));        foreach (DictionaryEntry _item in _resxReader)        {            if (_item.Key.Equals(key))            {                _value = _item.Value.ToString();                break;            }        }        return _value;    } span.fullpost {display:none;}

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• Creating Custom validation rule and register it

  - by FormsEleven

  What is Validation Rule? A validation rule is a piece of code that performs some check ensuring that data meets given constraints.In an enterprise application development environment, often it might require developers to have validation be performed based on some logic at several places across projects. Instead of redundant validation creation, a custom validation rule provides a library with a validation rules that can be registered and used across applications.A custom Validation is encapsulated in a reusable component so that you do not have to write it every time when you need to do input validation. Here is how we can easily implement a custom validation that checks for name of an employee to be "KING" For creating a custom Validation , 1.         Create Generic Application Workspace "CustomValidator" with the project "Model" 2.         Create an BC4J based on emp table. 3.         Create a custom validation rule.In EmpNamerule class, update the validateValue(..) method as follows:  public boolean validateValue(Object value) { EntityImpl emp = (EntityImpl)value; if(emp.getAttribute("Ename").toString().equals("KING")){ return false; } return true; } Create ADF Library: Next step would be to create ADF library. Create ADF library with name lets say testADFLibrary1.jarRegister ADF Library Next step is to register the ADF library , so that its available across the applications. Invoke the menu "Tools -> Preferences"Select the option "Business Components -> Registered Rules" from left paneClick on button "Pick Library". The dialog "Select Library" comes up with  the user library addedAdd new library' that points to the above jarCheck the checkbox "Register" and set the name for the rule Sample UsageHere is how we can easily implement a validation rule that restrict the name of the employee not to be "KING".Create new Application with BC4J based on EMP table.Create new validation under Business rule tab for Ename & select the above custom validation rule.Run the AppModule tester.

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• Unexpected issues with SessionPageStatePersiste

  - by geekrutherford

  Several iterations ago I implemented the SessionPageStatePersister in an application as a way to cut down on the size of the hidden ViewState input on aspx pages.   At first it seemed utterly fantasic. The size of the ViewState appeared to be drastically reduced and the application did not appear to peform any slower than baseline.   Enter the iFrame &amp; user control. I added a user control which pings the web server every 20 seconds in order to show updated application information to the user (new messages, reports, etc.) After releasing this nifty little control into the QA environment I quickly began receiving emails from testers about "post back" related error messages which mostly centered around invalid ViewState exceptions.   At first I dismissed it as something related to all of the AJAX requests happening on the page and considered turning off page event validation. However, upon further investigation I came across the following article:   Things That You Should Watch Out For When Using SessionPageStatePersister   In this article the author specifically states:   If you application uses frames than each frame request will create a new session view state item and as before it will remove items when reaching the maximum, you come into a situation that one of the frames will probably loose it session view state because other frames did post backs.   Oh snap! That is precisely what I am doing. That combined with multiple users on the application equals dropped ViewStates!   The temporary fix has been to disable the use of the SessionPageStatePersister in my application. This results in a bloated hidden ViewState input, but the web server is no longer tasked with maintaing/retreiving it and the app. no longer loses ViewState information.

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• Algorithm to figure out appointment times?

  - by Rachel

  I have a weird situation where a client would like a script that automatically sets up thousands of appointments over several days. The tricky part is the appointments are for a variety of US time zones, and I need to take the consumer's local time zone into account when generating appointment dates and times for each record. Appointment Rules: Appointments should be set from 8AM to 8PM Eastern Standard Time, with breaks from 12P-2P and 4P-6P. This leaves a total of 8 hours per day available for setting appointments. Appointments should be scheduled 5 minutes apart. 8 hours of 5-minute intervals means 96 appointments per day. There will be 5 users at a time handling appointments. 96 appointments per day multiplied by 5 users equals 480, so the maximum number of appointments that can be set per day is 480. Now the tricky requirement: Appointments are restricted to 8am to 8pm in the consumer's local time zone. This means that the earliest time allowed for each appointment is different depending on the consumer's time zone: Eastern: 8A Central: 9A Mountain: 10A Pacific: 11A Alaska: 12P Hawaii or Undefined: 2P Arizona: 10A or 11A based on current Daylight Savings Time Assuming a data set can be several thousand records, and each record will contain a timezone value, is there an algorithm I could use to determine a Date and Time for every record that matches the rules above?

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• Is there a way to add unique items to an array without doing a ton of comparisons?

  - by hydroparadise

  Please bare with me, I want this to be as language agnostic as possible becuase of the languages I am working with (One of which is a language called PowerOn). However, most languanges support for loops and arrays. Say I have the following list in an aray: 0x 0 Foo 1x 1 Bar 2x 0 Widget 3x 1 Whatsit 4x 0 Foo 5x 1 Bar Anything with a 1 should be uniqely added to another array with the following result: 0x 1 Bar 1x 1 Whatsit Keep in mind this is a very elementry example. In reality, I am dealing with 10's of thousands of elements on the old list. Here is what I have so far. Pseudo Code: For each element in oldlist For each element in newlist Compare If values oldlist.element equals newlist.element, break new list loop If reached end of newlist with with nothing equal from oldlist, add value from old list to new list End End Is there a better way of doing this? Algorithmicly, is there any room for improvement? And as a bonus qeustion, what is the O notation for this type of algorithm (if there is one)?

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• How can I bind a custom color to WPF toolkit ColorPicker? [on hold]

  - by tube-builder

  I need to bind the SelectedColor property of ColorPicker to a custom color which is not present in available colors. I created a simple test to show my problem. My xaml: <xctk:ColorPicker SelectedColor="{Binding Path=Test}"></xctk:ColorPicker> Code behind (CurrentStyle.PenColor returns an integer value which equals 13109765): public Color Test { get; set; } public MyClass() { DataContext = this; Test = Color.FromArgb((byte)((CurrentStyle.PenColor >> 24) & 0xFF), (byte)((CurrentStyle.PenColor >> 16) & 0xFF), (byte)((CurrentStyle.PenColor >> 8) & 0xFF), (byte)(CurrentStyle.PenColor & 0xFF)); InitializeComponent(); } And that's how my ColorPicker looks like when the window is loaded (I don't have enough rep to post images so it's just links): http://s22.postimg.org/frzh2fgy9/image.png Though, when I go to Advanced colors I can see that the color has been recognized and set correctly. Here is a pic: http://s13.postimg.org/gjv4cmy07/image.png Hope for your help. Thanks a lot! EDIT I implemented INotifyPropertyChanged, still to no avail. Here's the code: public Color Test { get { return test; } set { if (test != value) { test = value; OnPropertyChanged("Test"); } } } public event PropertyChangedEventHandler PropertyChanged; protected void OnPropertyChanged(string prop) { if (this.PropertyChanged != null) this.PropertyChanged(this, new PropertyChangedEventArgs(prop)); } Maybe I'm doing smth wrong here.

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• Syntax logic suggestions

  - by Anna

  This syntax will be used inside HTML attributes. Here are a few examples of what I have so far: <input name="a" conditions="!b, c" /> <input name="b" /> <input name="c" /> This will make input "a" do something if b is not checked and c is checked (b and c are assumed to be checkboxes if they don't have a :value defined) <input name="a" conditions="!b:foo|bar, c:foo" /> <input name="b" /> <input name="c" /> This will make input "a" do something if bdoesn't have foo or bar values, and if c has the foo value. <input name="a" conditions="!b:EMPTY" /> <input name="b" /> Makes input "a" do something if b has a value assigned. So, essentially , acts as logical AND, : as equals (=), ! as NOT, and | as OR. The | (OR) is only needed between values (at least I think so), and AND is not needed between values for obvious reasons :) EMPTY means empty value, like <input value="" /> Do you have any suggestions on improving this syntax, like making it more human friendly? For example I think the "EMPTY" keyword is not really appropriate and should be replaced with a character, but I don't know which one to choose.

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• Should I create my own Assert class based on these reasons?

  - by Mike

  The main reason I don't like Debug.Assert is the fact that these assertions are disabled in Release. I know that there's a performance reason for that, but at least in my situation I believe the gains would outweigh the cost. (By the way, I'm guessing this is the situation in most cases). And yes, I know that you can use Trace.Assert instead. But even though that would work, I find the name Trace distracting, since I don't see this as tracing. The other reason to create my own class is laziness I guess, since I could write methods for the most usual cases like Assert.IsNotNull, Assert.Equals and so forth. The second part of my question has to do with using Environment.FailFast in this class. Would that be a good idea? I do like the ideas put forth in this document. That's pretty much where I got the idea from. One last point. Does creating a design like this imply having an untestable code path, as described in this answer by Eric Lippert on a different (but related) question?

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• Architecture Standards &ndash; BPMN vs. BPEL for Business Process Management

  - by pat.shepherd

  I get asked often which business process standard an organization should use; BPMN or BPEL?  As I explain to folks, they both have strengths.  Here is a great article that helps understand the benefits of both and where to use them.  The good news is that, with Oracle SOA Suite and BPM suite, you have the option and flexibility to use both in the same SCA model and runtime container.  Good stuff. Here is the great article that Mark Nelson wrote: The right tool for the right job BPEL and BPMN are both ‘languages’ or ‘notations’ for describing and executing business processes. Both are open standards. Most business process engines will support one or the other of these languages. Oracle however has chosen to support both and treat them as equals. This means that you have the freedom to choose which language to use on a process by process basis. And you can freely mix and match, even within a single composite. (A composite is the deployment unit in an SCA environment.) So why support both? Well it turns out that BPEL is really well suited to modeling some kinds of processes and BPMN is really well suited to modeling other kinds of processes. Of course there is a pretty significant overlap where either will do a great job What BPM adds to SOA Suite | RedStack

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• Trying to use OpenGL in Java on Netbeans but getting an error. Please help [migrated]

  - by Steven Rogers

  I am on a Mac running Netbeans 6.9. I downloaded and installed LWJGL using this tutorial down to the letter: http://lwjgl.org/wiki/index.php?title=Setting_Up_LWJGL_with_NetBeans I finished the installation and copied sample code to see if my system is working. I got a bug, and was not sure if it was because of faulty code or i was doing something wrong. So i shortened down the code to this little simple bit: package javaopengl; import org.lwjgl.Sys; import org.lwjgl.opengl.Display; //Testing public class Main { public static void main(String[] args) { boolean fullscreen = (args.length == 1 && args[0].equals("-fullscreen")); try { Display.create(); Display.destroy(); } catch (Exception e) { e.printStackTrace(System.err); } System.exit(0); } } But i still get the same error, this is the error that i get: run: Exception in thread "main" java.lang.NoClassDefFoundError: = Caused by: java.lang.ClassNotFoundException: = at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:247) Java Result: 1 BUILD SUCCESSFUL (total time: 0 seconds) I am not sure what exactly is going on, Would you please tell me what is going on and how to fix it? It would be greatly appreciated, and thank you. Note: When i am looking at the text in the development environment, it does not show those red lines indicating there are any errors.

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• How to subtract 1 from a orginal count in an ASP.NET gridview

  - by SAMIR BHOGAYTA

  I have a gridview that contains a count (whic is Quantity) were i have a button that adds a row under the orginal row and i need the sub row's count (Quantity) to subtract one from the orgianl row Quantity. EX: Before button click Orgianl row = 3 After click Orginal row = 2 Subrow = 1 Code: ASP.NET // FUNCTION : Adds a new subrow protected void gvParent_RowCommand(object sender, GridViewCommandEventArgs e) { if (e.CommandName.Equals("btn_AddRow", StringComparison.OrdinalIgnoreCase)) { // Get the row that was clicked (index 0. Meaning that 0 is 1, 1 is 2 and so on) // Objects can be null, Int32s cannot not. // Int16 = 2 bytes long (short) // Int32 = 4 bytes long (int) // Int64 = 8 bytes long (long) int i = Convert.ToInt32(e.CommandArgument); // create a DataTable based off the view state DataTable dataTable = (DataTable)ViewState["gvParent"]; for (int part = 0; part 1) { dataTable.Rows[part]["Quantity"] = oldQuantitySubtract - 1; // Instert a new row at a specific index DataRow dtAdd = dataTable.NewRow(); for (int k = 0; k dtAdd[k] = dataTable.Rows[part][k]; dataTable.Rows.InsertAt(dtAdd, i + 1); break; //dataTable.Rows.Add(dtAdd); } } // Rebind the data gvParent.DataSource = dataTable; gvParent.DataBind(); } }

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• Monitoring settings in a configsection of your app.config for changes

  - by dotjosh

  The usage:public static void Main() { using(var configSectionAdapter = new ConfigurationSectionAdapter<ACISSInstanceConfigSection>("MyConfigSectionName")) { configSectionAdapter.ConfigSectionChanged += () => { Console.WriteLine("File has changed! New setting is " + configSectionAdapter.ConfigSection.MyConfigSetting); }; Console.WriteLine("The initial setting is " + configSectionAdapter.ConfigSection.MyConfigSetting); Console.ReadLine(); } }  The meat: public class ConfigurationSectionAdapter<T> : IDisposable where T : ConfigurationSection { private readonly string _configSectionName; private FileSystemWatcher _fileWatcher; public ConfigurationSectionAdapter(string configSectionName) { _configSectionName = configSectionName; StartFileWatcher(); } private void StartFileWatcher() { var configurationFileDirectory = new FileInfo(Configuration.FilePath).Directory; _fileWatcher = new FileSystemWatcher(configurationFileDirectory.FullName); _fileWatcher.Changed += FileWatcherOnChanged; _fileWatcher.EnableRaisingEvents = true; } private void FileWatcherOnChanged(object sender, FileSystemEventArgs args) { var changedFileIsConfigurationFile = string.Equals(args.FullPath, Configuration.FilePath, StringComparison.OrdinalIgnoreCase); if (!changedFileIsConfigurationFile) return; ClearCache(); OnConfigSectionChanged(); } private void ClearCache() { ConfigurationManager.RefreshSection(_configSectionName); } public T ConfigSection { get { return (T)Configuration.GetSection(_configSectionName); } } private System.Configuration.Configuration Configuration { get { return ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None); } } public delegate void ConfigChangedHandler(); public event ConfigChangedHandler ConfigSectionChanged; protected void OnConfigSectionChanged() { if (ConfigSectionChanged != null) ConfigSectionChanged(); } public void Dispose() { _fileWatcher.Changed -= FileWatcherOnChanged; _fileWatcher.EnableRaisingEvents = false; _fileWatcher.Dispose(); } }

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• Reloading Resources on Resume

  - by Siddharth

  I'm having a problem with my game. If I press the "Home button" the game is paused... everythings fine, but if I then go back to the game all the resources are reloaded before I can continue the game. And it takes quite a bit. Is this normal, or is there a way to avoid the reloading? I have write following code in onResume and onPause method. It loads same texture again and again on resume of game. @Override protected void onPause() { super.onPause(); if (Utility.flagSound && mScene != null) { if (mScene.getUserData().equals(Constants.GAME_SCENE)) Utility.isPlayLevelMusic = false; else Utility.isPlayLevelMusic = true; audioManager.gameBgMusic.pause(); audioManager.levelBgMusic.pause(); } if (this.mEngine != null && this.mEngine.isRunning()) { this.mEngine.stop(); } } @Override protected void onResume() { super.onResume(); if (audioManager != null && Utility.flagSound && dataManager != null) { if (Utility.flagSound) { if (Utility.isPlayLevelMusic) audioManager.levelBgMusic.play(); else audioManager.gameBgMusic.play(); } } if (this.mEngine != null && !this.mEngine.isRunning()) { this.mEngine.start(); } } I would be glad if anybody could help...

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• A* Start path finding in HTML5 Canvas

  - by gyhgowvi

  I'm trying implement A* Start path finding in my games(which are written with JavaScript, HTML5 Canvas). Library for A* Start found this - http://46dogs.blogspot.com/2009/10/star-pathroute-finding-javascript-code.html and now I'm using this library for path finding. And with this library, I'm trying write a simple test, but stuck with one problem. I'm now done when in HTML5 canvas screen click with mouse show path until my mouse.x and mouse.y. Here is a screenshot - http://oi46.tinypic.com/14qxrl.jpg (Pink square: Player, Orange squares: path until my mouse.x/mouse.y) Code how I'm drawing the orange squares until my mouse.x/mouse.y is: 'http://pastebin.com/bfq74ybc (Sorry I do not understand how upload code in my post) My problem is I do not understand how to move my player until path goal. I've tried: 'http://pastebin.com/nVW3mhUM But with this code my player is not beung drawn.(When I run the code, player.x and player.y are equals to 0 and when I click with the mouse I get the path player blink and disappear) Maybe anyone know how to solve this problem? And I'm very very very sorry for my bad English language. :)

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• Embedded Nashorn in JEditorPane

  - by Geertjan

  Here's a prototype for some kind of backoffice content management system. Several interesting goodies are included, such as an embedded JavaScript editor, as can be seen in the screenshot: Key items of interest in the above are as follows: Embedded JavaScript editor (i.e., the latest and greatest Nashorn technology, look it up, if you're not aware of what that is.) The way that's done is to include the relevant JavaScript modules in your NetBeans Platform application. Make very sure to include "Lexer to NetBeans Bridge", which does a bunch of critical stuff under the hood. The JEditorPane is defined as follows, along the lines that I blogged about recently thanks to Steven Yi: javaScriptPane.setContentType("text/javascript"); EditorKit kit = CloneableEditorSupport.getEditorKit("text/javascript"); javaScriptPane.setEditorKit(kit); javaScriptPane.getDocument().putProperty("mimeType", "text/javascript"); Note that "javaScriptPane" above is simply a JEditorPane. Timon Veenstra's excellent solution for integrating Nodes with MultiViewElements, which is described here by Timon, and nowhere else in the world. The tab you see above is within a pluggable container, so anyone else could create a new module and register their own MultiViewElement such that it will be incorporated into the editor. A small trick to ensure that only one window opens per news item: @NbBundle.Messages("OpenNews=Open") private class OpenNewsAction extends AbstractAction { public OpenNewsAction() { super(Bundle.OpenNews()); } @Override public void actionPerformed(ActionEvent e) { News news = getLookup().lookup(News.class); Mode editorMode = WindowManager.getDefault().findMode("editor"); for (TopComponent tc : WindowManager.getDefault().getOpenedTopComponents(editorMode)) { if (tc.getDisplayName().equals(news.getTitle())) { tc.requestActive(); return; } } TopComponent tc = MultiViews.createMultiView("application/x-newsnode", NewsNode.this); tc.open(); tc.requestActive(); } } The rest of what you see above is all standard NetBeans Platform stuff. The sources of everything you see above is here: http://java.net/projects/nb-api-samples/sources/api-samples/show/versions/7.3/misc/CMSBackOffice

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