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• Which tools to use and how to find file descriptors leaking from Glassfish?

  - by cclark

  We release new code to production every week and Glassfish hasn't had any problems. This weekend we had to move racks at our hosting provider. There were not any code changes (they just powered off, moved, re-racked and powered on) but we're on a new network infrastructure and suddenly we're leaking file descriptors like a sieve. So I'm guessing there is some sort of connection attempting to be made which now fails due to a network change. I'm running Glassfish v2ur2-b04/AS9.1_02 on RHEL4 with an embedded IMQ instance. After the move I started seeing: [#|2010-04-25T05:34:02.783+0000|SEVERE|sun-appserver9.1|javax.enterprise.system.container.web|_ThreadID=33;_ThreadName=SelectorThread-?4848;_RequestID=c4de6f6d-c1d6-416d-ac6e-49750b1a36ff;|WEB0756: Caught exception during HTTP processing. java.io.IOException: Too many open files at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method) ... [#|2010-04-25T05:34:03.327+0000|WARNING|sun-appserver9.1|javax.enterprise.system.stream.err|_ThreadID=34;_ThreadName=Timer-1;_RequestID=d27e1b94-d359-4d90-a6e3-c7ec49a0f383;|java.lang.NullPointerException at com.sun.jbi.management.system.AutoAdminTask.pollAutoDirectory(AutoAdminTask.java:1031) Using lsof I check the number of file descriptors and I see quite a few entries which look like: java 18510 root 8556u sock 0,4 1555182 can't identify protocol java 18510 root 8557u sock 0,4 1555320 can't identify protocol java 18510 root 8558u sock 0,4 1555736 can't identify protocol java 18510 root 8559u sock 0,4 1555883 can't identify protocol If I do a count of open file descriptors every minute I see it growing by 12 every minute. I have no idea what these sockets are. I've undeployed my application so there is only a plain Glassfish instance running and I still see it leaking 12 file descriptors a minute. So I think this leak is in Glassfish or potentially IMQ. What approach should I take to tracking down these sockets of unknown protocol? What tools can I use (or flags can I pass to lsof) to get more information about where to look? thanks, chuck

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• Stored procedure woes ... inserting binary ...

  - by Wardy

  Ok so I have this storedproc in my SQL 2008 database (works in 2005 too / used to) ... CREATE PROCEDURE [dbo].[SetBinaryContent] @Ref nvarchar(50), @Content varbinary(MAX), @ObjectID uniqueidentifier AS BEGIN DELETE ObjectContent WHERE ObjectId = @ObjectID AND Ref = @Ref IF DATALENGTH(@Content) > 5 BEGIN INSERT INTO ObjectContent (Ref,BinaryContent,ObjectId) VALUES (@Ref,@Content,@ObjectId) END UPDATE Objects SET [Status] = 1 WHERE ID = @ObjectID END Relatively simple, I take a byte array in C# and chuck it in @Content i then give it a guid and string for the other params and off we go. ... Great, it used to work ... but it don't anymore ... so erm ... What's wrong with this stored proc? I've stepped through my C# code thinking I screwed up somehow in that but it definately adds the params and gives them the correct values so what would cause the server to just stop executing this storedproc correctly? When called this proc executes but nothing changes in the db ... no new records are added to the ObjectContent table. Weird huh ...

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• Django Database design -- Is this a good stragety for overriding defaults

  - by rh0dium

  Hi SO's I have a question on good database design practices and I would like to leverage you guys for pointers. The project started out simple. Hey we have a bunch of questions we want answered for every project (no problem) Which turned into... Hey we have so many questions can we group them into sections (yup we can do that) Which lead into.. Can we weight these questions and I don't really want some of these questions for my project (Yes but we are getting difficult) And then I'm thinking they will want to have each section have it's own weight.. Requirements So there's the requirements - For n number of project Allow a admin member the ability select the questions for a project Allow the admin member to re-weigh or use the default weights for the questions Allow the admin member to re-weight the sections Allow team members to answer the questions. So here is what I came up with. Please feel free to comment and provide better examples models.py from django.db import models from django.contrib.sites.models import Site from django.conf import settings class Section(models.Model): """ This describes the various sections for a checklist: """ name = models.CharField(max_length=64) description = models.TextField() class Question(models.Model): """ This simply provides a simple way to list out the questions. """ question = models.CharField(max_length=255) answer_type = models.CharField(max_length=16) description = models.TextField() section = models.ForeignKey(Section) class ProjectQuestion(models.Model): """ These are the questions relevant to the project """ question = models.ForeignKey(Question) answer = models.CharField(max_length=255) required = models.BooleanField(default=True) weight = models.FloatField(default = XXX) class Project(models.Model): """ Here is where we want to gather our questions """ questions = models.ManyToManyField(ProjectQuestion) Immediate questions: - When I start a project - any ideas on how to "pre-populate" the questions (and ultimately the weights) for the project? - Is there a generally accepted method for doing this process that I am missing? Basically the idea that you refer to the questions overide your own default weight, and store the answer? - It appears that a good chuck of the work will be done in the views and that a lot of checking will need to occur there? Is that OK? Again - feel free to give me better strategies!! Thanks

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• Program structure in long running data processing python script

  - by fmark

  For my current job I am writing some long-running (think hours to days) scripts that do CPU intensive data-processing. The program flow is very simple - it proceeds into the main loop, completes the main loop, saves output and terminates: The basic structure of my programs tends to be like so: <import statements> <constant declarations> <misc function declarations> def main(): for blah in blahs(): <lots of local variables> <lots of tightly coupled computation> for something in somethings(): <lots more local variables> <lots more computation> <etc., etc.> <save results> if __name__ == "__main__": main() This gets unmanageable quickly, so I want to refactor it into something more manageable. I want to make this more maintainable, without sacrificing execution speed. Each chuck of code relies on a large number of variables however, so refactoring parts of the computation out to functions would make parameters list grow out of hand very quickly. Should I put this sort of code into a python class, and change the local variables into class variables? It doesn't make a great deal of sense tp me conceptually to turn the program into a class, as the class would never be reused, and only one instance would ever be created per instance. What is the best practice structure for this kind of program? I am using python but the question is relatively language-agnostic, assuming a modern object-oriented language features.

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• NSFetchedResultsController on secondary UITableView - how to query data?

  - by Jason

  I am creating a core-data based Navigation iPhone app with multiple screens. Let's say it is a flash-card application. The data model is very simple, with only two entities: Language, and CardSet. There is a one-to-many relationship between the Language entity and the CardSet entities, so each Language may contain multiple CardSets. In other words, Language has a one-to-many relationship Language.cardSets which points to the list of CardSets, and CardSet has a relationship CardSet.language which points to the Language. There are two screens: (1) An initial TableView screen, which displays the list of languages; and (2) a secondary TableView screen, which displays the list of CardSets in the Language. In the initial screen, which lists the languages, I am using NSFetchedResultsController to keep the list of languages up-to-date. The screen passes the Language selected to the secondary screen. On the secondary screen, I am trying to figure out whether I should again use an NSFetchedResultsController to maintain the list of CardSets, or if I should work through Language.cardSets to simply pull the list out of the object model. The latter makes the most sense programatically because I already have the Language - but then it would not automatically be updated on changes. I have looked at the NSFetchedResultsController documentation, and it seems like I can easily create predicates based on attributes - but not relationships. I.e., I can create the following NSFetchedResultsController: NSPredicate *predicate = [NSPredicate predicateWithFormat:@"name LIKE[c] 'Chuck Norris'"]; How can I access my data through the direct relationship - Language.cardSets - and also have the table auto-update using NSFetchedResultsController? Is this possible?

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• print friendly version of floated list

  - by Brad

  I have a list of phone extensions that I want to print a friendly version of it. I have a print css for it to print appropriately onto paper, the extensions are located within an unordered list, which are floated to the left. <ul> <li>Larry Hughes <span class="ext">8291</span></li> <li>Chuck Davis <span class="ext">3141</span></li> <li>Kevin Skillis <span class="ext">5115</span></li> </ul> I float it left, and when it prints the second page, it leaves off the name part of the list (in Firefox, works fine in Google Chrome and IE), see here: http://cl.ly/de965aea63f66c13ba32 I am referring to this: http://www.alistapart.com/articles/goingtoprint/ - they mentioned something about applying a float:none; to the content part of the page. If I do that, how should I go about making the list show up in 4 columns? It is a dynamic list, pulled from a database. Any help is appreciated.

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• Profit's COLLABORATE 10 Session Selections

  - by Aaron Lazenby

  COLLABORATE 2010 is a mere 11 days away (thanks for the reminder @ocp_advisor). Every year I publish my a list of the sessions I think reflect some of the more interesting people/trends in enterprise IT. I should be at all of these sessions, so drop by for a chat--I'll be the guy tapping out emails on my iPad... Monday, April 19 9:15 a.m. - Keynote: Transforming Customer Value, Delivering Highest Customer Service Location: Keynote Hall I never miss Charles Phillips when he speaks--it's one of the best opportunities to get an update on Oracle product developments and strategy. And there's certainly occasion for an update: this will be Phillips' first big presentation since the Oracle + Sun Strategy Update in late January. Phillips is appearing with Oracle Executive Vice President of Development Thomas Kurian which means there should be some excellent information about how customers are using Oracle's complete software and hardware stack to address enterprise IT challenges. The session should provide some excellent context for the rest of the week's session...don't miss it. 10:45 a.m. - Oracle Fusion Applications: Functional Overview Location: South Seas FI met Basheer Khan at COLLABORATE 08 in Denver and have followed his work ever since. He's a former member of the OAUG Board of Directors, an Oracle ACE, and a charismatic enterprise IT expert. Having worked with the Oracle Usability Advisory Board, Basheer should have some fascinating insights to share about the features and interface of Oracle's Fusine Applications. This session, along with Nadia Bendjedou's "10 Things You Can Do Today to Prepare for the Next Generation Applications" (on Tuesday, April 20 8:00 a.m. in room 3662) should give attendees the update they need about Oracle's next-generation applications.   1:15p.m. - E-Business Suite in the Amazon Cloud Location: South Seas HI did my first full-fledged cloud computing coverage at last year's COLLABORATE show (check out my interview with Oracle's Bill Hodak), where I first learned about Amazon's EC2 offering. I've since talked with several people who have provisioned server space on Amazon's cloud with great results. So I'm looking forward to watching the audience configure an instance of the Oracle E-Business Suite release 12 on the cloud while Chuck Edwards from Blue Gecko drives. This session should take some of the mist and vapor out of the cloud conversation.2:30 p.m. - "Zero Sign-on" to EBS - Enabling 96000 Users to Login to EBS Without User Maintenance Location: South Seas HI'll be sitting tight in South Seas H for the next session on Monday where Doug Pepka, a ten-year veteran of communications giant Comcast, will be walking attendees through a massive single sign-on (SSO) project across the enterprise. I'm working on a story about SSO for the August issue of Profit, so this session has real practical value to me. Plus the proliferation of user account logins--both personal and professional--makes this a critical usability/change management issue for IT leaders planning for successful long-term IT implementations.   Tuesday 8:00 am  - Information Architecture for Men in Kilts Location: SURF AGetting to a 8:00 a.m. presentation is a tall order in Las Vegas, but presenter Billy Cripe will make it worth your effort. Not only is the title of this session great, but the content should appeal to any IT strategist looking to push the limits of Web 2.0 technologies in the enterprise. Cripe is a product management director of Enterprise 2.0 and Enterprise Content Management at Oracle, author of Reshaping Your Business with Web 2.0, and a prolific blogger--he knows how information architecture is critical to and enterprise 2.0 implementation.    10:30a.m. - Oracle Virtualization: From Desktop to Data Center Location: REEF FData center virtualization is still one of the best ways to reduce the cost of running enterprise IT. With the addition of Sun products, Oracle has the industry's most comprehensive virtualization portfolio. I must admit, I'm no expert in this subject. So I'm looking forward to Monica Kumar's presentation so I can get up to speed.   Wednesday 8:00 a.m. - The Art of the Steal Location: Mandalay Bay Ballroom JMany will know Frank Abagnale from Steven Spielberg's 2002 film "Catch Me if You Can." The one-time con man and international fugitive who swindled $2.5 million in forged checks went on to help U.S. federal officials investigate fraud cases. Now the CEO of Abagnale and Associates, he has become an invaluable source to the business world on the subject of fraud and fraud protection. With identity theft and digital fraud still on the rise, this session should be an entertaining, and sobering, education on the threats facing businesses and customers around the world. A great way to start Wednesday.1:00 p.m. - Google Wave: Will it replace e-mail as we know it today? Location: SURF EBy many assessments (my own included), Google Wave is a bit of an open collaboration failure. It may seem like an odd reason for me to be excited about this session, but I'm looking forward to the chance to revisit the technology. Also, this is a great case study in connecting free, available Internet tools to existing enterprise computing environments--an issue that IT strategists must contend with as workers spreads out and choose their own productivity tools.  

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• How to structure game states in an entity/component-based system

  - by Eva

  I'm making a game designed with the entity-component paradigm that uses systems to communicate between components as explained here. I've reached the point in my development that I need to add game states (such as paused, playing, level start, round start, game over, etc.), but I'm not sure how to do it with my framework. I've looked at this code example on game states which everyone seems to reference, but I don't think it fits with my framework. It seems to have each state handling its own drawing and updating. My framework has a SystemManager that handles all the updating using systems. For example, here's my RenderingSystem class: public class RenderingSystem extends GameSystem { private GameView gameView_; /** * Constructor * Creates a new RenderingSystem. * @param gameManager The game manager. Used to get the game components. */ public RenderingSystem(GameManager gameManager) { super(gameManager); } /** * Method: registerGameView * Registers gameView into the RenderingSystem. * @param gameView The game view registered. */ public void registerGameView(GameView gameView) { gameView_ = gameView; } /** * Method: triggerRender * Adds a repaint call to the event queue for the dirty rectangle. */ public void triggerRender() { Rectangle dirtyRect = new Rectangle(); for (GameObject object : getRenderableObjects()) { GraphicsComponent graphicsComponent = object.getComponent(GraphicsComponent.class); dirtyRect.add(graphicsComponent.getDirtyRect()); } gameView_.repaint(dirtyRect); } /** * Method: renderGameView * Renders the game objects onto the game view. * @param g The graphics object that draws the game objects. */ public void renderGameView(Graphics g) { for (GameObject object : getRenderableObjects()) { GraphicsComponent graphicsComponent = object.getComponent(GraphicsComponent.class); if (!graphicsComponent.isVisible()) continue; GraphicsComponent.Shape shape = graphicsComponent.getShape(); BoundsComponent boundsComponent = object.getComponent(BoundsComponent.class); Rectangle bounds = boundsComponent.getBounds(); g.setColor(graphicsComponent.getColor()); if (shape == GraphicsComponent.Shape.RECTANGULAR) { g.fill3DRect(bounds.x, bounds.y, bounds.width, bounds.height, true); } else if (shape == GraphicsComponent.Shape.CIRCULAR) { g.fillOval(bounds.x, bounds.y, bounds.width, bounds.height); } } } /** * Method: getRenderableObjects * @return The renderable game objects. */ private HashSet<GameObject> getRenderableObjects() { return gameManager.getGameObjectManager().getRelevantObjects( getClass()); } } Also all the updating in my game is event-driven. I don't have a loop like theirs that simply updates everything at the same time. I like my framework because it makes it easy to add new GameObjects, but doesn't have the problems some component-based designs encounter when communicating between components. I would hate to chuck it just to get pause to work. Is there a way I can add game states to my game without removing the entity-component design? Does the game state example actually fit my framework, and I'm just missing something? EDIT: I might not have explained my framework well enough. My components are just data. If I was coding in C++, they'd probably be structs. Here's an example of one: public class BoundsComponent implements GameComponent { /** * The position of the game object. */ private Point pos_; /** * The size of the game object. */ private Dimension size_; /** * Constructor * Creates a new BoundsComponent for a game object with initial position * initialPos and initial size initialSize. The position and size combine * to make up the bounds. * @param initialPos The initial position of the game object. * @param initialSize The initial size of the game object. */ public BoundsComponent(Point initialPos, Dimension initialSize) { pos_ = initialPos; size_ = initialSize; } /** * Method: getBounds * @return The bounds of the game object. */ public Rectangle getBounds() { return new Rectangle(pos_, size_); } /** * Method: setPos * Sets the position of the game object to newPos. * @param newPos The value to which the position of the game object is * set. */ public void setPos(Point newPos) { pos_ = newPos; } } My components do not communicate with each other. Systems handle inter-component communication. My systems also do not communicate with each other. They have separate functionality and can easily be kept separate. The MovementSystem doesn't need to know what the RenderingSystem is rendering to move the game objects correctly; it just need to set the right values on the components, so that when the RenderingSystem renders the game objects, it has accurate data. The game state could not be a system, because it needs to interact with the systems rather than the components. It's not setting data; it's determining which functions need to be called. A GameStateComponent wouldn't make sense because all the game objects share one game state. Components are what make up objects and each one is different for each different object. For example, the game objects cannot have the same bounds. They can have overlapping bounds, but if they share a BoundsComponent, they're really the same object. Hopefully, this explanation makes my framework less confusing.

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• JLabel animation in JPanel

  - by Trizicus

  After scratching around I found that it's best to implement a custom image component by extending a JLabel. So far that has worked great as I can add multiple "images" (jlabels without the layout breaking. I just have a question that I hope someone can answer for me. I noticed that in order to animate JLabels across the screen I need to setlayout(null); and setbounds of the component and then to animate eventually setlocation(x,y);. Is this a best practice or a terrible way to animate a component? I plan on eventually making an animation class but I don't want to do so and end up having to chuck it. I have included relevant code for a quick review check. import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JPanel; import javax.swing.Timer; public class GraphicsPanel extends JPanel { private Timer timer; private long startTime = 0; private int numFrames = 0; private float fps = 0.0f; private int x = 0; GraphicsPanel() { final Entity ent1 = new Entity(); ent1.setBounds(x, 0, ent1.getWidth(), ent1.getHeight()); add(ent1); //ESSENTIAL setLayout(null); //GAMELOOP timer = new Timer(30, new ActionListener() { public void actionPerformed(ActionEvent e) { getFPS(); incX(); ent1.setLocation(x, 0); repaint(); } }); timer.start(); } public void incX() { x++; } @Override public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D) g.create(); g2.setClip(0, 0, getWidth(), getHeight()); g2.setColor(Color.BLACK); g2.drawString("FPS: " + fps, 1, 15); } public void getFPS() { ++numFrames; if (startTime == 0) { startTime = System.currentTimeMillis(); } else { long currentTime = System.currentTimeMillis(); long delta = (currentTime - startTime); if (delta > 1000) { fps = (numFrames * 1000) / delta; numFrames = 0; startTime = currentTime; } } } } Thank you!

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• SQLite3 table not accepting INSERT INTO statements. The table is created, and so is the database, but nothing is passed into it

  - by user1460029

  <?php try { //open the database $db = new PDO('sqlite:music.db'); $db->exec("DELETE from Music;"); $db->exec("INSERT INTO Music(Title, Author, ReleaseDate) VALUES ('Whatd I Say', 'Ray Charles', '1956');" . "INSERT INTO Music(Title, Author, ReleaseDate) VALUES ('Smells Like Teen Spirit.', 'Nirvana', '1991');" . "INSERT INTO Music(Title, Author, ReleaseDate) VALUES ('Hey Jude', 'The Beatles', '1968');" . "INSERT INTO Music(Title, Author, ReleaseDate) VALUES ('Johnny B. Goode', 'Chuck Berry', '1958');" . "INSERT INTO Music(Title, Author, ReleaseDate) VALUES ('Good Vibrations', 'The Beach Boys', '1966');" . "INSERT INTO Music(Title, Author, ReleaseDate) VALUES ('Respect', 'Aretha Franklin', '1967');" . "INSERT INTO Music(Title, Author, ReleaseDate) VALUES ('Whats Going On', 'Marvin Gaye', '1971');" . "INSERT INTO Music(Title, Author, ReleaseDate) VALUES ('Imagine', 'John Lennon', '1971');" . "INSERT INTO Music(Title, Author, ReleaseDate) VALUES ('(I Cant Get No) Satisfaction', 'Rolling Stones', '1965');" . "INSERT INTO Music(Title, Author, ReleaseDate) VALUES ('Like A Rolling Stone', 'Bob Dylan', '1965');"); //now output the data to a simple html table... //example of specifier --> WHERE First=\'Josh\'; <-- print "<table border=1>"; print "<tr><td>Title</td><td>Author</td><td>Y.O.P.</td></tr>"; $result = $db->query('SELECT * FROM Music '); foreach($result as $row) { print "<td>".$row['Title']."</td>"; print "<td>".$row['Author']."</td>"; print "<td>".$row['ReleaseDate']."</td></tr>"; } print "</table>"; $db = NULL; } catch(PDOException $e) { print 'Exception : '.$e->getMessage(); } ?> I am not sure why nothing is being inserted into the table. The file 'music.db' exists in the right path. For the record, I can only use SQlite3, no SQL allowed. PHP is allowed, so is SQLite3.

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• Handling exceptions raised in observers

  - by sparky

  I have a Rails (2.3.5) application where there are many groups, and each Group has_many People. I have a Group edit form where users can create new people. When a new person is created, they are sent an email (the email address is user entered on the form). This is accomplished with an observer on the Person model. The problem comes when ActionMailer throws an exception - for example if the domain does not exist. Clearly that cannot be weeded out with a validation. There would seem to be 2 ways to deal with this: A begin...rescue...end block in the observer around the mailer. The problem with this is that the only way to pass any feedback to the user would be to set a global variable - as the observer is out of the MVC flow, I can't even set a flash[:error] there. A rescue_from in the Groups controller. This works fine, but has 2 problems. Firstly, there is no way to know which person threw the exception (all I can get is the 503 exception, no way to know which person caused the problem). This would be useful information to be able to pass back to the user - at the moment, there is no way for me to let them know which email address is the problem - at the moment, I just have to chuck the lot back at them, and issue an unhelpful message saying that one of them is not correct. Secondly (and to a certain extent this make the first point moot) it seems that it is necessary to call a render in the rescue_from, or it dies with a rather bizarre "can't convert Array into String" error from webbrick, with no stack trace & nothing in the log. Thus, I have to throw it back to the user when I come across the first error and have to stop processing the rest of the emails. Neither of the solutions are optimal. It would seem that the only way to get Rails to do what I want is option 1, and loathsome global variables. This would also rely on Rails being single threaded. Can anyone suggest a better solution to this problem?

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• Setup and Use SpecFlow BDD with DevExpress XAF

  - by Patrick Liekhus

  Let’s get started with using the SpecFlow BDD syntax for writing tests with the DevExpress XAF EasyTest scripting syntax.  In order for this to work you will need to download and install the prerequisites listed below.  Once they are installed follow the steps outlined below and enjoy. Prerequisites Install the following items: DevExpress eXpress Application Framework (XAF) found here SpecFlow found here Liekhus BDD/XAF Testing library found here Assumptions I am going to assume at this point that you have created your XAF application and have your Module, Win.Module and Win ready for usage.  You should have also set any attributes and/or settings as you see fit. Setup So where to start. Create a new testing project within your solution. I typically call this with a similar naming convention as used by XAF, my project name .FunctionalTests (i.e. AlbumManager.FunctionalTests). Add the following references to your project.  It should look like the reference list below. DevExpress.Data.v11.x DevExpress.Persistent.Base.v11.x DevExpress.Persistent.BaseImpl.v11.x DevExpress.Xpo.v11.2 Liekhus.Testing.BDD.Core Liekhus.Testing.BDD.DevExpress TechTalk.SpecFlow TestExecutor.v11.x (found in %Program Files%\DevExpress 2011.x\eXpressApp Framework\Tools\EasyTest Right click the TestExecutor reference and set the “Copy Local” setting to True.  This forces the TestExecutor executable to be available in the bin directory which is where the EasyTest script will be executed further down in the process. Add an Application Configuration File (app.config) to your test application.  You will need to make a few modifications to have SpecFlow generate Microsoft style unit tests.  First add the section handler for SpecFlow and then set your choice of testing framework.  I prefer MS Tests for my projects. Add the EasyTest configuration file to your project.  Add a new XML file and call it Config.xml. Open the properties window for the Config.xml file and set the “Copy to Ouput Directory” to “Copy Always”. You will setup the Config file according to the specifications of the EasyTest library my mapping to your executable and other settings.  You can find the details for the configuration of EasyTest here.  My file looks like this Create a new folder in your test project called “StepDefinitions”.  Add a new SpecFlow Step Definition file item under the StepDefinitions folder.  I typically call this class StepDefinition.cs. Have your step definition inherit from the Liekhus.Testing.BDD.DevExpress.StepDefinition class.  This will give you the default behaviors for your test in the next section. OK.  Now that we have done this series of steps, we will work on simplifying this.  This is an early preview of this new project and is not fully ready for consumption.  If you would like to experiment with it, please feel free.  Our goals are to make this a installable project on it’s own with it’s own project templates and default settings.  This will be coming in later versions.  Currently this project is in Alpha release. Let’s write our first test Remove the basic test that is created for you. We will not use the default test but rather create our own SpecFlow “Feature” files. Add a new item to your project and select the SpecFlow Feature file under C#. Name your feature file as you do your class files after the test they are performing. Writing a feature file uses the Cucumber syntax of Given… When… Then.  Think of it in these terms.  Givens are the pre-conditions for the test.  The Whens are the actual steps for the test being performed.  The Thens are the verification steps that confirm your test either passed or failed.  All of these steps are generated into a an EasyTest format and executed against your XAF project.  You can find more on the Cucumber syntax by using the Secret Ninja Cucumber Scrolls.  This document has several good styles of tests, plus you can get your fill of Chuck Norris vs Ninjas.  Pretty humorous document but full of great content. My first test is going to test the entry of a new Album into the application and is outlined below. The Feature section at the top is more for your documentation purposes.  Try to be descriptive of the test so that it makes sense to the next person behind you.  The Scenario outline is described in the Ninja Scrolls, but think of it as test template.  You can write one test outline and have multiple datasets (Scenarios) executed against that test.  Here are the steps of my test and their descriptions Given I am starting a new test – tells our test to create a new EasyTest file And (Given) the application is open – tells EasyTest to open our application defined in the Config.xml When I am at the “Albums” screen – tells XAF to navigate to the Albums list view And (When) I click the “New:Album” button – tells XAF to click the New Album button on the ribbon And (When) I enter the following information – tells XAF to find the field on the screen and put the value in that field And (When) I click the “Save and Close” button – tells XAF to click the “Save and Close” button on the detail window Then I verify results as “user” – tells the testing framework to execute the EasyTest as your configured user Once you compile and prepare your tests you should see the following in your Test View.  For each of your CreateNewAlbum lines in your scenarios, you will see a new test ready to execute. From here you will use your testing framework of choice to execute the test.  This in turn will execute the EasyTest framework to call back into your XAF application and test your business application. Again, please remember that this is an early preview and we are still working out the details.  Please let us know if you have any comments/questions/concerns. Thanks and happy testing.

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• SSIS: Deploying OLAP cubes using C# script tasks and AMO

  - by DrJohn

  As part of the continuing series on Building dynamic OLAP data marts on-the-fly, this blog entry will focus on how to automate the deployment of OLAP cubes using SQL Server Integration Services (SSIS) and Analysis Services Management Objects (AMO). OLAP cube deployment is usually done using the Analysis Services Deployment Wizard. However, this option was dismissed for a variety of reasons. Firstly, invoking external processes from SSIS is fraught with problems as (a) it is not always possible to ensure SSIS waits for the external program to terminate; (b) we cannot log the outcome properly and (c) it is not always possible to control the server's configuration to ensure the executable works correctly. Another reason for rejecting the Deployment Wizard is that it requires the 'answers' to be written into four XML files. These XML files record the three things we need to change: the name of the server, the name of the OLAP database and the connection string to the data mart. Although it would be reasonably straight forward to change the content of the XML files programmatically, this adds another set of complication and level of obscurity to the overall process. When I first investigated the possibility of using C# to deploy a cube, I was surprised to find that there are no other blog entries about the topic. I can only assume everyone else is happy with the Deployment Wizard! SSIS "forgets" assembly references If you build your script task from scratch, you will have to remember how to overcome one of the major annoyances of working with SSIS script tasks: the forgetful nature of SSIS when it comes to assembly references. Basically, you can go through the process of adding an assembly reference using the Add Reference dialog, but when you close the script window, SSIS "forgets" the assembly reference so the script will not compile. After repeating the operation several times, you will find that SSIS only remembers the assembly reference when you specifically press the Save All icon in the script window. This problem is not unique to the AMO assembly and has certainly been a "feature" since SQL Server 2005, so I am not amazed it is still present in SQL Server 2008 R2! Sample Package So let's take a look at the sample SSIS package I have provided which can be downloaded from here: DeployOlapCubeExample.zip  Below is a screenshot after a successful run. Connection Managers The package has three connection managers: AsDatabaseDefinitionFile is a file connection manager pointing to the .asdatabase file you wish to deploy. Note that this can be found in the bin directory of you OLAP database project once you have clicked the "Build" button in Visual Studio TargetOlapServerCS is an Analysis Services connection manager which identifies both the deployment server and the target database name. SourceDataMart is an OLEDB connection manager pointing to the data mart which is to act as the source of data for your cube. This will be used to replace the connection string found in your .asdatabase file Once you have configured the connection managers, the sample should run and deploy your OLAP database in a few seconds. Of course, in a production environment, these connection managers would be associated with package configurations or set at runtime. When you run the sample, you should see that the script logs its activity to the output screen (see screenshot above). If you configure logging for the package, then these messages will also appear in your SSIS logging. Sample Code Walkthrough Next let's walk through the code. The first step is to parse the connection string provided by the TargetOlapServerCS connection manager and obtain the name of both the target OLAP server and also the name of the OLAP database. Note that the target database does not have to exist to be referenced in an AS connection manager, so I am using this as a convenient way to define both properties. We now connect to the server and check for the existence of the OLAP database. If it exists, we drop the database so we can re-deploy. svr.Connect(olapServerName); if (svr.Connected) { // Drop the OLAP database if it already exists Database db = svr.Databases.FindByName(olapDatabaseName); if (db != null) { db.Drop(); } // rest of script } Next we start building the XMLA command that will actually perform the deployment. Basically this is a small chuck of XML which we need to wrap around the large .asdatabase file generated by the Visual Studio build process. // Start generating the main part of the XMLA command XmlDocument xmlaCommand = new XmlDocument(); xmlaCommand.LoadXml(string.Format("<Batch Transaction='false' xmlns='http://schemas.microsoft.com/analysisservices/2003/engine'><Alter AllowCreate='true' ObjectExpansion='ExpandFull'><Object><DatabaseID>{0}</DatabaseID></Object><ObjectDefinition/></Alter></Batch>", olapDatabaseName));  Next we need to merge two XML files which we can do by simply using setting the InnerXml property of the ObjectDefinition node as follows: // load OLAP Database definition from .asdatabase file identified by connection manager XmlDocument olapCubeDef = new XmlDocument(); olapCubeDef.Load(Dts.Connections["AsDatabaseDefinitionFile"].ConnectionString); // merge the two XML files by obtain a reference to the ObjectDefinition node oaRootNode.InnerXml = olapCubeDef.InnerXml;   One hurdle I had to overcome was removing detritus from the .asdabase file left by the Visual Studio build. Through an iterative process, I found I needed to remove several nodes as they caused the deployment to fail. The XMLA error message read "Cannot set read-only node: CreatedTimestamp" or similar. In comparing the XMLA generated with by the Deployment Wizard with that generated by my code, these read-only nodes were missing, so clearly I just needed to strip them out. This was easily achieved using XPath to find the relevant XML nodes, of which I show one example below: foreach (XmlNode node in rootNode.SelectNodes("//ns1:CreatedTimestamp", nsManager)) { node.ParentNode.RemoveChild(node); } Now we need to change the database name in both the ID and Name nodes using code such as: XmlNode databaseID = xmlaCommand.SelectSingleNode("//ns1:Database/ns1:ID", nsManager); if (databaseID != null) databaseID.InnerText = olapDatabaseName; Finally we need to change the connection string to point at the relevant data mart. Again this is easily achieved using XPath to search for the relevant nodes and then replace the content of the node with the new name or connection string. XmlNode connectionStringNode = xmlaCommand.SelectSingleNode("//ns1:DataSources/ns1:DataSource/ns1:ConnectionString", nsManager); if (connectionStringNode != null) { connectionStringNode.InnerText = Dts.Connections["SourceDataMart"].ConnectionString; } Finally we need to perform the deployment using the Execute XMLA command and check the returned XmlaResultCollection for errors before setting the Dts.TaskResult. XmlaResultCollection oResults = svr.Execute(xmlaCommand.InnerXml);  // check for errors during deployment foreach (Microsoft.AnalysisServices.XmlaResult oResult in oResults) { foreach (Microsoft.AnalysisServices.XmlaMessage oMessage in oResult.Messages) { if ((oMessage.GetType().Name == "XmlaError")) { FireError(oMessage.Description); HadError = true; } } } If you are not familiar with XML programming, all this may all seem a bit daunting, but perceiver as the sample code is pretty short. If you would like the script to process the OLAP database, simply uncomment the lines in the vicinity of Process method. Of course, you can extend the script to perform your own custom processing and to even synchronize the database to a front-end server. Personally, I like to keep the deployment and processing separate as the code can become overly complex for support staff.If you want to know more, come see my session at the forthcoming SQLBits conference.

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• random generator to obtain data from array not displaying

  - by Yang Jie Domodomo

  I know theres a better solution using arc4random (it's on my to-try-out-function list), but I wanted to try out using the rand() and stand(time(NULL)) function first. I've created a NSMutableArray and chuck it with 5 data. Testing out how many number it has was fine. But when I tried to use the button function to load the object it return me with object <sampleData: 0x9a2f0e0> - (IBAction)generateNumber:(id)sender { srand(time(NULL)); NSInteger number =rand()% ds.count ; label.text = [NSString stringWithFormat:@"object %@", [ds objectAtIndex:number] ]; NSLog(@"%@",label.text); } While I feel the main cause is the method itself, I've paste the rest of the code below just incase i made any error somewhere. ViewController.h #import <UIKit/UIKit.h> #import "sampleData.h" #import "sampleDataDAO.h" @interface ViewController : UIViewController @property (weak, nonatomic) IBOutlet UILabel *label; @property (weak, nonatomic) IBOutlet UIButton *onHitMePressed; - (IBAction)generateNumber:(id)sender; @property(nonatomic, strong) sampleDataDAO *daoDS; @property(nonatomic, strong) NSMutableArray *ds; @end ViewController.m #import "ViewController.h" @interface ViewController () @end @implementation ViewController @synthesize label; @synthesize onHitMePressed; @synthesize daoDS,ds; - (void)viewDidLoad { [super viewDidLoad]; daoDS = [[sampleDataDAO alloc] init]; self.ds = daoDS.PopulateDataSource; // Do any additional setup after loading the view, typically from a nib. } - (void)viewDidUnload { [self setLabel:nil]; [self setOnHitMePressed:nil]; [super viewDidUnload]; // Release any retained subviews of the main view. } - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown); } - (IBAction)generateNumber:(id)sender { srand(time(NULL)); NSInteger number =rand()% ds.count ; label.text = [NSString stringWithFormat:@"object %@", [ds objectAtIndex:number] ]; NSLog(@"%@",label.text); } @end sampleData.h #import <Foundation/Foundation.h> @interface sampleData : NSObject @property (strong,nonatomic) NSString * object; @end sampleData.m #import "sampleData.h" @implementation sampleData @synthesize object; @end sampleDataDAO.h #import <Foundation/Foundation.h> #import "sampleData.h" @interface sampleDataDAO : NSObject @property(strong,nonatomic)NSMutableArray*someDataArray; -(NSMutableArray *)PopulateDataSource; @end sampleDataDAO.m #import "sampleDataDAO.h" @implementation sampleDataDAO @synthesize someDataArray; -(NSMutableArray *)PopulateDataSource { someDataArray = [[NSMutableArray alloc]init]; sampleData * myData = [[sampleData alloc]init]; myData.object= @"object 1"; [someDataArray addObject:myData]; myData=nil; myData = [[sampleData alloc] init]; myData.object= @"object 2"; [someDataArray addObject:myData]; myData=nil; myData = [[sampleData alloc] init]; myData.object= @"object 3"; [someDataArray addObject:myData]; myData=nil; myData = [[sampleData alloc] init]; myData.object= @"object 4"; [someDataArray addObject:myData]; myData=nil; myData = [[sampleData alloc] init]; myData.object= @"object 5"; [someDataArray addObject:myData]; myData=nil; return someDataArray; } @end

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• reorder XML elements or set an explicit template with XSLT

  - by Sash

  I tried the solution in my previous question (flattening XML to load via SSIS package), however this isn't working. I now know what I need to do, however I need some guidance on how to do it. So say I have the following XML structure: <person id="1"> <name>John</name> <surname>Smith</surname> <age>25</age> <comment> <comment_id>1</comment_id> <comment_text>Hello</comment_text> </comment> <comment> <comment_id>2</comment_id> <comment_text>Hello again!</comment_text> </comment> <somethingelse> <id>1</id> </somethingelse> <comment> <comment_id>3</comment_id> <comment_text>Third Item</comment_text> </comment> </person> <person id="2"> <name>John</name> <surname>Smith</surname> <age>25</age> <somethingelse> <id>1</id> </somethingelse> </person> ... ... If I am to load this into a SSIS package, as an XML source, what I will essentially get is a table created for each element, as opposed to get a structured table output such as person table (name, surname, age) somethingelse table (id) comment table (comment_id, comment_text) What I end up getting is: person table (person_Id <-- internal SSIS id) name table surname table age table person_name table person_surname table person_comment_comment_id table etc... What I found was that if each element and all inner elements are not in the same format and consistency, i will get the above anomaly which makes it rather complex especially if I am dealing with 80 - 100+ columns. Unfortunately I have no way of modifying the system (Lotus Notes) that produces these reports, so I was wondering whether I may be able to explicitly have an XSLT template that will be able to align each person sub elements (and the sub collection elements such as comments ? Unless there is a quicker way to realign all inner elements. Seems that SSIS XML source requires a very consistent XML file in the sense of: if the name element is in position 1, then all subsequent name elements within person parent have to be in position 1. SSIS seems to pickup the inconsistencies if there are certain elements missing from one parent to another, however, if their ordering is not right (A, B, C)(A, B, C)(A,C,B), it will chuck a massive fuss! All help is appreciated! Thank you in advance.

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• C#: Why Decorate When You Can Intercept

  - by James Michael Hare

  We've all heard of the old Decorator Design Pattern (here) or used it at one time or another either directly or indirectly.  A decorator is a class that wraps a given abstract class or interface and presents the same (or a superset) public interface but "decorated" with additional functionality.   As a really simplistic example, consider the System.IO.BufferedStream, it itself is a descendent of System.IO.Stream and wraps the given stream with buffering logic while still presenting System.IO.Stream's public interface:   1: Stream buffStream = new BufferedStream(rawStream); Now, let's take a look at a custom-code example.  Let's say that we have a class in our data access layer that retrieves a list of products from a database:  1: // a class that handles our CRUD operations for products 2: public class ProductDao 3: { 4: ... 5:  6: // a method that would retrieve all available products 7: public IEnumerable<Product> GetAvailableProducts() 8: { 9: var results = new List<Product>(); 10:  11: // must create the connection 12: using (var con = _factory.CreateConnection()) 13: { 14: con.ConnectionString = _productsConnectionString; 15: con.Open(); 16:  17: // create the command 18: using (var cmd = _factory.CreateCommand()) 19: { 20: cmd.Connection = con; 21: cmd.CommandText = _getAllProductsStoredProc; 22: cmd.CommandType = CommandType.StoredProcedure; 23:  24: // get a reader and pass back all results 25: using (var reader = cmd.ExecuteReader()) 26: { 27: while(reader.Read()) 28: { 29: results.Add(new Product 30: { 31: Name = reader["product_name"].ToString(), 32: ... 33: }); 34: } 35: } 36: } 37: }            38:  39: return results; 40: } 41: } Yes, you could use EF or any myriad other choices for this sort of thing, but the germaine point is that you have some operation that takes a non-trivial amount of time.  What if, during the production day I notice that my application is performing slowly and I want to see how much of that slowness is in the query versus my code.  Well, I could easily wrap the logic block in a System.Diagnostics.Stopwatch and log the results to log4net or other logging flavor of choice: 1:     // a class that handles our CRUD operations for products 2:     public class ProductDao 3:     { 4:         private static readonly ILog _log = LogManager.GetLogger(typeof(ProductDao)); 5:         ... 6:         7:         // a method that would retrieve all available products 8:         public IEnumerable<Product> GetAvailableProducts() 9:         { 10:             var results = new List<Product>(); 11:             var timer = Stopwatch.StartNew(); 12:             13:             // must create the connection 14:             using (var con = _factory.CreateConnection()) 15:             { 16:                 con.ConnectionString = _productsConnectionString; 17:                 18:                 // and all that other DB code... 19:                 ... 20:             } 21:             22:             timer.Stop(); 23:             24:             if (timer.ElapsedMilliseconds > 5000) 25:             { 26:                 _log.WarnFormat("Long query in GetAvailableProducts() took {0} ms", 27:                     timer.ElapsedMillseconds); 28:             } 29:             30:             return results; 31:         } 32:     } In my eye, this is very ugly.  It violates Single Responsibility Principle (SRP), which says that a class should only ever have one responsibility, where responsibility is often defined as a reason to change.  This class (and in particular this method) has two reasons to change: If the method of retrieving products changes. If the method of logging changes. Well, we could “simplify” this using the Decorator Design Pattern (here).  If we followed the pattern to the letter, we'd need to create a base decorator that implements the DAOs public interface and forwards to the wrapped instance.  So let's assume we break out the ProductDAO interface into IProductDAO using your refactoring tool of choice (Resharper is great for this). Now, ProductDao will implement IProductDao and get rid of all logging logic: 1:     public class ProductDao : IProductDao 2:     { 3:         // this reverts back to original version except for the interface added 4:     } 5:  And we create the base Decorator that also implements the interface and forwards all calls: 1:     public class ProductDaoDecorator : IProductDao 2:     { 3:         private readonly IProductDao _wrappedDao; 4:         5:         // constructor takes the dao to wrap 6:         public ProductDaoDecorator(IProductDao wrappedDao) 7:         { 8:             _wrappedDao = wrappedDao; 9:         } 10:         11:         ... 12:         13:         // and then all methods just forward their calls 14:         public IEnumerable<Product> GetAvailableProducts() 15:         { 16:             return _wrappedDao.GetAvailableProducts(); 17:         } 18:     } This defines our base decorator, then we can create decorators that add items of interest, and for any methods we don't decorate, we'll get the default behavior which just forwards the call to the wrapper in the base decorator: 1:     public class TimedThresholdProductDaoDecorator : ProductDaoDecorator 2:     { 3:         private static readonly ILog _log = LogManager.GetLogger(typeof(TimedThresholdProductDaoDecorator)); 4:         5:         public TimedThresholdProductDaoDecorator(IProductDao wrappedDao) : 6:             base(wrappedDao) 7:         { 8:         } 9:         10:         ... 11:         12:         public IEnumerable<Product> GetAvailableProducts() 13:         { 14:             var timer = Stopwatch.StartNew(); 15:             16:             var results = _wrapped.GetAvailableProducts(); 17:             18:             timer.Stop(); 19:             20:             if (timer.ElapsedMilliseconds > 5000) 21:             { 22:                 _log.WarnFormat("Long query in GetAvailableProducts() took {0} ms", 23:                     timer.ElapsedMillseconds); 24:             } 25:             26:             return results; 27:         } 28:     } Well, it's a bit better.  Now the logging is in its own class, and the database logic is in its own class.  But we've essentially multiplied the number of classes.  We now have 3 classes and one interface!  Now if you want to do that same logging decorating on all your DAOs, imagine the code bloat!  Sure, you can simplify and avoid creating the base decorator, or chuck it all and just inherit directly.  But regardless all of these have the problem of tying the logging logic into the code itself. Enter the Interceptors.  Things like this to me are a perfect example of when it's good to write an Interceptor using your class library of choice.  Sure, you could design your own perfectly generic decorator with delegates and all that, but personally I'm a big fan of Castle's Dynamic Proxy (here) which is actually used by many projects including Moq. What DynamicProxy allows you to do is intercept calls into any object by wrapping it with a proxy on the fly that intercepts the method and allows you to add functionality.  Essentially, the code would now look like this using DynamicProxy: 1: // Note: I like hiding DynamicProxy behind the scenes so users 2: // don't have to explicitly add reference to Castle's libraries. 3: public static class TimeThresholdInterceptor 4: { 5: // Our logging handle 6: private static readonly ILog _log = LogManager.GetLogger(typeof(TimeThresholdInterceptor)); 7:  8: // Handle to Castle's proxy generator 9: private static readonly ProxyGenerator _generator = new ProxyGenerator(); 10:  11: // generic form for those who prefer it 12: public static object Create<TInterface>(object target, TimeSpan threshold) 13: { 14: return Create(typeof(TInterface), target, threshold); 15: } 16:  17: // Form that uses type instead 18: public static object Create(Type interfaceType, object target, TimeSpan threshold) 19: { 20: return _generator.CreateInterfaceProxyWithTarget(interfaceType, target, 21: new TimedThreshold(threshold, level)); 22: } 23:  24: // The interceptor that is created to intercept the interface calls. 25: // Hidden as a private inner class so not exposing Castle libraries. 26: private class TimedThreshold : IInterceptor 27: { 28: // The threshold as a positive timespan that triggers a log message. 29: private readonly TimeSpan _threshold; 30:  31: // interceptor constructor 32: public TimedThreshold(TimeSpan threshold) 33: { 34: _threshold = threshold; 35: } 36:  37: // Intercept functor for each method invokation 38: public void Intercept(IInvocation invocation) 39: { 40: // time the method invocation 41: var timer = Stopwatch.StartNew(); 42:  43: // the Castle magic that tells the method to go ahead 44: invocation.Proceed(); 45:  46: timer.Stop(); 47:  48: // check if threshold is exceeded 49: if (timer.Elapsed > _threshold) 50: { 51: _log.WarnFormat("Long execution in {0} took {1} ms", 52: invocation.Method.Name, 53: timer.ElapsedMillseconds); 54: } 55: } 56: } 57: } Yes, it's a bit longer, but notice that: This class ONLY deals with logging long method calls, no DAO interface leftovers. This class can be used to time ANY class that has an interface or virtual methods. Personally, I like to wrap and hide the usage of DynamicProxy and IInterceptor so that anyone who uses this class doesn't need to know to add a Castle library reference.  As far as they are concerned, they're using my interceptor.  If I change to a new library if a better one comes along, they're insulated. Now, all we have to do to use this is to tell it to wrap our ProductDao and it does the rest: 1: // wraps a new ProductDao with a timing interceptor with a threshold of 5 seconds 2: IProductDao dao = TimeThresholdInterceptor.Create<IProductDao>(new ProductDao(), 5000); Automatic decoration of all methods!  You can even refine the proxy so that it only intercepts certain methods. This is ideal for so many things.  These are just some of the interceptors we've dreamed up and use: Log parameters and returns of methods to XML for auditing. Block invocations to methods and return default value (stubbing). Throw exception if certain methods are called (good for blocking access to deprecated methods). Log entrance and exit of a method and the duration. Log a message if a method takes more than a given time threshold to execute. Whether you use DynamicProxy or some other technology, I hope you see the benefits this adds.  Does it completely eliminate all need for the Decorator pattern?  No, there may still be cases where you want to decorate a particular class with functionality that doesn't apply to the world at large. But for all those cases where you are using Decorator to add functionality that's truly generic.  I strongly suggest you give this a try!

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• The UIManager Pattern

  - by Duncan Mills

  One of the most common mistakes that I see when reviewing ADF application code, is the sin of storing UI component references, most commonly things like table or tree components in Session or PageFlow scope. The reasons why this is bad are simple; firstly, these UI object references are not serializable so would not survive a session migration between servers and secondly there is no guarantee that the framework will re-use the same component tree from request to request, although in practice it generally does do so. So there danger here is, that at best you end up with an NPE after you session has migrated, and at worse, you end up pinning old generations of the component tree happily eating up your precious memory. So that's clear, we should never. ever, be storing references to components anywhere other than request scope (or maybe backing bean scope). So double check the scope of those binding attributes that map component references into a managed bean in your applications.  Why is it Such a Common Mistake?  At this point I want to examine why there is this urge to hold onto these references anyway? After all, JSF will obligingly populate your backing beans with the fresh and correct reference when needed.   In most cases, it seems that the rational is down to a lack of distinction within the application between what is data and what is presentation. I think perhaps, a cause of this is the logical separation between business data behind the ADF data binding (#{bindings}) façade and the UI components themselves. Developers tend to think, OK this is my data layer behind the bindings object and everything else is just UI.  Of course that's not the case.  The UI layer itself will have state which is intrinsically linked to the UI presentation rather than the business model, but at the same time should not be tighly bound to a specific instance of any single UI component. So here's the problem.  I think developers try and use the UI components as state-holders for this kind of data, rather than using them to represent that state. An example of this might be something like the selection state of a tabset (panelTabbed), you might be interested in knowing what the currently disclosed tab is. The temptation that leads to the component reference sin is to go and ask the tabset what the selection is.  That of course is fine in context - e.g. a handler within the same request scoped bean that's got the binding to the tabset. However, it leads to problems when you subsequently want the same information outside of the immediate scope.  The simple solution seems to be to chuck that component reference into session scope and then you can simply re-check in the same way, leading of course to this mistake. Turn it on its Head  So the correct solution to this is to turn the problem on its head. If you are going to be interested in the value or state of some component outside of the immediate request context then it becomes persistent state (persistent in the sense that it extends beyond the lifespan of a single request). So you need to externalize that state outside of the component and have the component reference and manipulate that state as needed rather than owning it. This is what I call the UIManager pattern.  Defining the Pattern The  UIManager pattern really is very simple. The premise is that every application should define a session scoped managed bean, appropriately named UIManger, which is specifically responsible for holding this persistent UI component related state.  The actual makeup of the UIManger class varies depending on a needs of the application and the amount of state that needs to be stored. Generally I'll start off with a Map in which individual flags can be created as required, although you could opt for a more formal set of typed member variables with getters and setters, or indeed a mix. This UIManager class is defined as a session scoped managed bean (#{uiManager}) in the faces-config.xml.  The pattern is to then inject this instance of the class into any other managed bean (usually request scope) that needs it using a managed property.  So typically you'll have something like this:   <managed-bean>     <managed-bean-name>uiManager</managed-bean-name>     <managed-bean-class>oracle.demo.view.state.UIManager</managed-bean-class>     <managed-bean-scope>session</managed-bean-scope>   </managed-bean>  When is then injected into any backing bean that needs it:    <managed-bean>     <managed-bean-name>mainPageBB</managed-bean-name>     <managed-bean-class>oracle.demo.view.MainBacking</managed-bean-class>     <managed-bean-scope>request</managed-bean-scope>     <managed-property>       <property-name>uiManager</property-name>       <property-class>oracle.demo.view.state.UIManager</property-class>       <value>#{uiManager}</value>     </managed-property>   </managed-bean> In this case the backing bean in question needs a member variable to hold and reference the UIManager: private UIManager _uiManager;  Which should be exposed via a getter and setter pair with names that match the managed property name (e.g. setUiManager(UIManager _uiManager), getUiManager()).  This will then give your code within the backing bean full access to the UI state. UI components in the page can, of course, directly reference the uiManager bean in their properties, for example, going back to the tab-set example you might have something like this: <af:paneltabbed>   <af:showDetailItem text="First"                disclosed="#{uiManager.settings['MAIN_TABSET_STATE'].['FIRST']}"> ...   </af:showDetailItem>   <af:showDetailItem text="Second"                      disclosed="#{uiManager.settings['MAIN_TABSET_STATE'].['SECOND']}">     ...   </af:showDetailItem>   ... </af:panelTabbed> Where in this case the settings member within the UI Manger is a Map which contains a Map of Booleans for each tab under the MAIN_TABSET_STATE key. (Just an example you could choose to store just an identifier for the selected tab or whatever, how you choose to store the state within UI Manger is up to you.) Get into the Habit So we can see that the UIManager pattern is not great strain to implement for an application and can even be retrofitted to an existing application with ease. The point is, however, that you should always take this approach rather than committing the sin of persistent component references which will bite you in the future or shotgun scattered UI flags on the session which are hard to maintain.  If you take the approach of always accessing all UI state via the uiManager, or perhaps a pageScope focused variant of it, you'll find your applications much easier to understand and maintain. Do it today!

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