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• SQL SERVER – Beginning of SQL Server Architecture – Terminology – Guest Post

  - by pinaldave

  SQL Server Architecture is a very deep subject. Covering it in a single post is an almost impossible task. However, this subject is very popular topic among beginners and advanced users.  I have requested my friend Anil Kumar who is expert in SQL Domain to help me write  a simple post about Beginning SQL Server Architecture. As stated earlier this subject is very deep subject and in this first article series he has covered basic terminologies. In future article he will explore the subject further down. Anil Kumar Yadav is Trainer, SQL Domain, Koenig Solutions. Koenig is a premier IT training firm that provides several IT certifications, such as Oracle 11g, Server+, RHCA, SQL Server Training, Prince2 Foundation etc. In this Article we will discuss about MS SQL Server architecture. The major components of SQL Server are: Relational Engine Storage Engine SQL OS Now we will discuss and understand each one of them. 1) Relational Engine: Also called as the query processor, Relational Engine includes the components of SQL Server that determine what your query exactly needs to do and the best way to do it. It manages the execution of queries as it requests data from the storage engine and processes the results returned. Different Tasks of Relational Engine: Query Processing Memory Management Thread and Task Management Buffer Management Distributed Query Processing 2) Storage Engine: Storage Engine is responsible for storage and retrieval of the data on to the storage system (Disk, SAN etc.). to understand more, let’s focus on the following diagram. When we talk about any database in SQL server, there are 2 types of files that are created at the disk level – Data file and Log file. Data file physically stores the data in data pages. Log files that are also known as write ahead logs, are used for storing transactions performed on the database. Let’s understand data file and log file in more details: Data File: Data File stores data in the form of Data Page (8KB) and these data pages are logically organized in extents. Extents: Extents are logical units in the database. They are a combination of 8 data pages i.e. 64 KB forms an extent. Extents can be of two types, Mixed and Uniform. Mixed extents hold different types of pages like index, System, Object data etc. On the other hand, Uniform extents are dedicated to only one type. Pages: As we should know what type of data pages can be stored in SQL Server, below mentioned are some of them: Data Page: It holds the data entered by the user but not the data which is of type text, ntext, nvarchar(max), varchar(max), varbinary(max), image and xml data. Index: It stores the index entries. Text/Image: It stores LOB ( Large Object data) like text, ntext, varchar(max), nvarchar(max),  varbinary(max), image and xml data. GAM & SGAM (Global Allocation Map & Shared Global Allocation Map): They are used for saving information related to the allocation of extents. PFS (Page Free Space): Information related to page allocation and unused space available on pages. IAM (Index Allocation Map): Information pertaining to extents that are used by a table or index per allocation unit. BCM (Bulk Changed Map): Keeps information about the extents changed in a Bulk Operation. DCM (Differential Change Map): This is the information of extents that have modified since the last BACKUP DATABASE statement as per allocation unit. Log File: It also known as write ahead log. It stores modification to the database (DML and DDL). Sufficient information is logged to be able to: Roll back transactions if requested Recover the database in case of failure Write Ahead Logging is used to create log entries Transaction logs are written in chronological order in a circular way Truncation policy for logs is based on the recovery model SQL OS: This lies between the host machine (Windows OS) and SQL Server. All the activities performed on database engine are taken care of by SQL OS. It is a highly configurable operating system with powerful API (application programming interface), enabling automatic locality and advanced parallelism. SQL OS provides various operating system services, such as memory management deals with buffer pool, log buffer and deadlock detection using the blocking and locking structure. Other services include exception handling, hosting for external components like Common Language Runtime, CLR etc. I guess this brief article gives you an idea about the various terminologies used related to SQL Server Architecture. In future articles we will explore them further. Guest Author  The author of the article is Anil Kumar Yadav is Trainer, SQL Domain, Koenig Solutions. Koenig is a premier IT training firm that provides several IT certifications, such as Oracle 11g, Server+, RHCA, SQL Server Training, Prince2 Foundation etc. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Security, SQL Server, SQL Tips and Tricks, SQL Training, T SQL, Technology

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• Home Energy Management & Automation with Windows Phone 7

  A number of people at Clarity are personally interested in home energy conservation and home automation. We feel that a mobile device is a great fit for bringing this idea to fruition. While this project is merely a concept and not directly associated with Microsofts Hohm web service, it provides a great model for communicating the concept. I wanted to take the idea a step further and combine saving energy in your home with the ability to track water usage and control your home devices. I designed an application that focuses on total home control and not just energy usage. Application Overview By monitoring home consumption in real time and with yearly projections users can pinpoint vampire devices, times of high or low consumption, and wasteful patterns of energy use. Energy usage meters indicate total current consumption as well as individual device consumption. Users can then use the information to take action, make adjustments, and change their consumption behaviors. The app can be used to automate certain systems like lighting, temperature, or alarms. Other features can be turned on an off at the touch of a toggle switch on your phone, away from home. Forget to turn off the TV or shut the garage door? No problem, you can do it from your phone. Through settings you can enable and disable features of the phone that apply to your home making it a completely customized and convenient experience. To be clear, this equates to more security, big environmental impact, and even bigger savings.   Design and User Interface  Since this panorama application is designed for win phone 7 devices, it complies with the UI Design and Interaction Guide for wp7. I developed the frame and page hierarchy from existing examples. The interface takes advantage of the interactive nature of touch screens with slider controls, pivot control views, and toggle switches to turn on and off devices (not shown in mockup). I followed recommendations for text based elements and adapted the tile notifications to display the most recent user activity. For example, the mockup indicates upon launching the app that the last thing you did was program the thermostat. This model is great for quick launching common user actions. One last design feature to point out is the technical reasons for supplying both light and dark themes for the app. Since this application is targeting energy consumption it only makes sense to consider the effect of the apps background color or image on the phones energy use. When displaying darker colors like black the OLED display may use less power, extending battery life. Other Considerations For now I left out options of wind and solar powered energy options because they are not available to everyone. Renewable energy sources and new technologies associated with them are definitely ideas to keep in mind for a next iteration. Another idea to explore for such an application would be to include a savings model similar to mint.com. In addition to general energy-saving recommendations the application could recommend customized ways to save based on your current utility providers and available options in your area. If your television or refrigerator is guilty of sucking a lot of energy then you may see recommendations for energy star products that could save you even more money! Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Increase the size of Taskbar Preview Thumbnails in Windows 7

  - by Matthew Guay

  Taskbar thumbnail previews are incredibly useful in Windows 7, but for some users they may be too small.  Here’s a tool to help you make your taskbar thumbnail previews just like you want them. A few years ago we featured a tool to increase the size of your thumbnail previews in Windows Vista, but unfortunately this application doesn’t work correctly in Windows 7.  However, there is a new tool for Windows 7 that lets you customize your taskbar thumbnail previews even more in Windows 7.  With it, you can change almost anything about your taskbar thumbnail previews.  The default taskbar thumbnails are nice, but may be too small for users with vision problems or with very high resolution monitors.  Whatever your need, this is a great tool to make the thumbnails looks and work just like you want. Let’s get started Download the Windows 7 Taskbar Thumbnail Customizer (link below), and unzip the files.  Run the Windows 7 Taskbar Thumbnail Customizer when you’re done.  Simply double-click on it; you don’t need to run it as administrator. Now, you change the size, spacing, margin, and delay time of your taskbar thumbnails.  The Delay Time setting is very handy; to speed things up, we set it to 0 so there’s no delay between when you mouse-over a taskbar icon to when you see the thumbnail.  Simply drag the slider to the size (or time in the delay settings) you want, and click Apply settings.  Windows Explorer will automatically restart, and your new taskbar thumbnails will be ready to use. Here is the default Windows 7 thumbnail preview of a video playing in Media player: And here’s the taskbar thumbnail enlarged to 380px.  Now you can really watch a video from your taskbar thumbnail. The larger taskbar thumbnails show up a little different in Internet Explorer.  It shows a larger preview of your active tab, and smaller previews of your other tabs.  Notice also that Aero peek shows the tab you’re hovering over in Internet Explorer, but the tab name in IE’s toolbar doesn’t change to the one you’re previewing.   Here we increased the width between the thumbnails, while keeping the thumbnails at their default size.  This could be useful if you have trouble selecting the correct preview, and we can imagine it would be a very useful modification on touch screens. And, if you ever take your changes too far, and want to revert to your default Windows 7 taskbar thumbnail previews, simply run the Customizer again and select Restore Defaults.  Windows Explorer will restart again, and your taskbar thumbnails will be back to their default settings.   Conclusion This tool makes it safe and easy to change the size, spacing, and more of your taskbar thumbnail previews.  And since you can always revert to the default settings, you can experiment without fear of messing up your computer.  If you’d prefer to change the settings manually without using a dedicated application, here’s a list of the registry changes you can make to accomplish this by hand. Link Download the Windows 7 Taskbar Thumbnail Customizer from The Windows Club Vista Users: Increase Size of Windows Vista Taskbar Previews Similar Articles Productive Geek Tips Bounty(Paid!) for Increasing Windows Vista Taskbar Preview SizeGet Vista Taskbar Thumbnail Previews in Windows XPVista Style Popup Previews for Firefox TabsIncrease Size of Windows Vista Taskbar PreviewsWhat is dwm.exe And Why Is It Running? TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Are You Blocked On Gtalk? Find out Discover Latest Android Apps On AppBrain The Ultimate Guide For YouTube Lovers Will it Blend? iPad Edition Penolo Lets You Share Sketches On Twitter Visit Woolyss.com for Old School Games, Music and Videos

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• Class Loading Deadlocks

  - by tomas.nilsson

  Mattis follows up on his previous post with one more expose on Class Loading Deadlocks As I wrote in a previous post, the class loading mechanism in Java is very powerful. There are many advanced techniques you can use, and when used wrongly you can get into all sorts of trouble. But one of the sneakiest deadlocks you can run into when it comes to class loading doesn't require any home made class loaders or anything. All you need is classes depending on each other, and some bad luck. First of all, here are some basic facts about class loading: 1) If a thread needs to use a class that is not yet loaded, it will try to load that class 2) If another thread is already loading the class, the first thread will wait for the other thread to finish the loading 3) During the loading of a class, one thing that happens is that the <clinit method of a class is being run 4) The <clinit method initializes all static fields, and runs any static blocks in the class. Take the following class for example: class Foo { static Bar bar = new Bar(); static { System.out.println("Loading Foo"); } } The first time a thread needs to use the Foo class, the class will be initialized. The <clinit method will run, creating a new Bar object and printing "Loading Foo" But what happens if the Bar object has never been used before either? Well, then we will need to load that class as well, calling the Bar <clinit method as we go. Can you start to see the potential problem here? A hint is in fact #2 above. What if another thread is currently loading class Bar? The thread loading class Foo will have to wait for that thread to finish loading. But what happens if the <clinit method of class Bar tries to initialize a Foo object? That thread will have to wait for the first thread, and there we have the deadlock. Thread one is waiting for thread two to initialize class Bar, thread two is waiting for thread one to initialize class Foo. All that is needed for a class loading deadlock is static cross dependencies between two classes (and a multi threaded environment): class Foo { static Bar b = new Bar(); } class Bar { static Foo f = new Foo(); } If two threads cause these classes to be loaded at exactly the same time, we will have a deadlock. So, how do you avoid this? Well, one way is of course to not have these circular (static) dependencies. On the other hand, it can be very hard to detect these, and sometimes your design may depend on it. What you can do in that case is to make sure that the classes are first loaded single threadedly, for example during an initialization phase of your application. The following program shows this kind of deadlock. To help bad luck on the way, I added a one second sleep in the static block of the classes to trigger the unlucky timing. Notice that if you uncomment the "//Foo f = new Foo();" line in the main method, the class will be loaded single threadedly, and the program will terminate as it should. public class ClassLoadingDeadlock { // Start two threads. The first will instansiate a Foo object, // the second one will instansiate a Bar object. public static void main(String[] arg) { // Uncomment next line to stop the deadlock // Foo f = new Foo(); new Thread(new FooUser()).start(); new Thread(new BarUser()).start(); } } class FooUser implements Runnable { public void run() { System.out.println("FooUser causing class Foo to be loaded"); Foo f = new Foo(); System.out.println("FooUser done"); } } class BarUser implements Runnable { public void run() { System.out.println("BarUser causing class Bar to be loaded"); Bar b = new Bar(); System.out.println("BarUser done"); } } class Foo { static { // We are deadlock prone even without this sleep... // The sleep just makes us more deterministic try { Thread.sleep(1000); } catch(InterruptedException e) {} } static Bar b = new Bar(); } class Bar { static { try { Thread.sleep(1000); } catch(InterruptedException e) {} } static Foo f = new Foo(); }

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• Make Text and Images Easier to Read with the Windows 7 Magnifier

  - by DigitalGeekery

  Do you have impaired vision or find it difficult to read small print on your computer screen? Today, we’ll take a closer look at how to magnify that hard to read content with the Magnifier in Windows 7. Magnifier was available in previous versions of Windows, but the Windows 7 version comes with some notable improvements. There are now three screen modes in Magnifier. Full Screen and Lens mode, however, require Windows Aero to be enabled. If your computer doesn’t support Aero, or if you’re not using am Aero theme, Magnifier will only work in Docked mode. Using Magnifier in Windows 7 You can find the Magnifier by going to Start > All Programs > Accessories > Ease of Access > Magnifier.   Alternately, you can type magnifier into the Search box in the Start Menu and hit Enter. On the Magnifier toolbar, choose your View mode by clicking Views and choosing from the available options. Clicking the plus (+) and minus (-) buttons will zoom in or zoom out. You can change the zoom in/out percentage by adjusting the slider bar. You can also enable color inversion and select tracking options. Click OK when finished to save your settings.   After a brief period, the Magnifier Toolbar will switch to a magnifying glass icon. Simply click the magnifying glass to display the Magnifier Toolbar again.   Docked Mode In Docked mode, a portion of the screen is magnified and docked at the top of the screen. The rest of your desktop will remain in it’s normal state. You can then control which area of the screen is magnified by moving your mouse.   Full Screen Mode This magnifies your entire screen and follows your mouse as you move it around. If you loose track of where you are on the screen, use the Ctrl + Alt + Spacebar shortcut to preview where your mouse pointer is on the screen.   Lens Mode The Lens screen mode is similar to holding a magnifying glass up to your screen. Full screen mode magnifies the area around the mouse. The magnified area moves around the screen with your mouse.    Shortcut Keys Windows key + (+) to zoom in Windows key + (-) to zoom out Windows key + ESC to exit Ctrl + Alt + F – Full screen mode Ctrl + Alt + L – Lens mode Ctrl + Alt + D – Dock mode Ctrl + Alt + R – Resize the lens Ctrl + Alt + Spacebar – Preview full screen Conclusion Windows Magnifier is a nice little tool if you have impaired vision or just need to make items on the screen easier to read. Similar Articles Productive Geek Tips New Features in WordPad and Paint in Windows 7How-To Geek on Lifehacker: How to Make Windows Vista Less AnnoyingUsing Comments in Word 2007 DocumentsMake Your PC Look Like Windows Phone 7Use Image Placeholders to Display Documents Faster in Word TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips HippoRemote Pro 2.2 Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Windows Media Player Plus! – Cool WMP Enhancer Get Your Team’s World Cup Schedule In Google Calendar Backup Drivers With Driver Magician TubeSort: YouTube Playlist Organizer XPS file format & XPS Viewer Explained Microsoft Office Web Apps Guide

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• Why lock-free data structures just aren't lock-free enough

  - by Alex.Davies

  Today's post will explore why the current ways to communicate between threads don't scale, and show you a possible way to build scalable parallel programming on top of shared memory. The problem with shared memory Soon, we will have dozens, hundreds and then millions of cores in our computers. It's inevitable, because individual cores just can't get much faster. At some point, that's going to mean that we have to rethink our architecture entirely, as millions of cores can't all access a shared memory space efficiently. But millions of cores are still a long way off, and in the meantime we'll see machines with dozens of cores, struggling with shared memory. Alex's tip: The best way for an application to make use of that increasing parallel power is to use a concurrency model like actors, that deals with synchronisation issues for you. Then, the maintainer of the actors framework can find the most efficient way to coordinate access to shared memory to allow your actors to pass messages to each other efficiently. At the moment, NAct uses the .NET thread pool and a few locks to marshal messages. It works well on dual and quad core machines, but it won't scale to more cores. Every time we use a lock, our core performs an atomic memory operation (eg. CAS) on a cell of memory representing the lock, so it's sure that no other core can possibly have that lock. This is very fast when the lock isn't contended, but we need to notify all the other cores, in case they held the cell of memory in a cache. As the number of cores increases, the total cost of a lock increases linearly. A lot of work has been done on "lock-free" data structures, which avoid locks by using atomic memory operations directly. These give fairly dramatic performance improvements, particularly on systems with a few (2 to 4) cores. The .NET 4 concurrent collections in System.Collections.Concurrent are mostly lock-free. However, lock-free data structures still don't scale indefinitely, because any use of an atomic memory operation still involves every core in the system. A sync-free data structure Some concurrent data structures are possible to write in a completely synchronization-free way, without using any atomic memory operations. One useful example is a single producer, single consumer (SPSC) queue. It's easy to write a sync-free fixed size SPSC queue using a circular buffer*. Slightly trickier is a queue that grows as needed. You can use a linked list to represent the queue, but if you leave the nodes to be garbage collected once you're done with them, the GC will need to involve all the cores in collecting the finished nodes. Instead, I've implemented a proof of concept inspired by this intel article which reuses the nodes by putting them in a second queue to send back to the producer. * In all these cases, you need to use memory barriers correctly, but these are local to a core, so don't have the same scalability problems as atomic memory operations. Performance tests I tried benchmarking my SPSC queue against the .NET ConcurrentQueue, and against a standard Queue protected by locks. In some ways, this isn't a fair comparison, because both of these support multiple producers and multiple consumers, but I'll come to that later. I started on my dual-core laptop, running a simple test that had one thread producing 64 bit integers, and another consuming them, to measure the pure overhead of the queue. So, nothing very interesting here. Both concurrent collections perform better than the lock-based one as expected, but there's not a lot to choose between the ConcurrentQueue and my SPSC queue. I was a little disappointed, but then, the .NET Framework team spent a lot longer optimising it than I did. So I dug out a more powerful machine that Red Gate's DBA tools team had been using for testing. It is a 6 core Intel i7 machine with hyperthreading, adding up to 12 logical cores. Now the results get more interesting. As I increased the number of producer-consumer pairs to 6 (to saturate all 12 logical cores), the locking approach was slow, and got even slower, as you'd expect. What I didn't expect to be so clear was the drop-off in performance of the lock-free ConcurrentQueue. I could see the machine only using about 20% of available CPU cycles when it should have been saturated. My interpretation is that as all the cores used atomic memory operations to safely access the queue, they ended up spending most of the time notifying each other about cache lines that need invalidating. The sync-free approach scaled perfectly, despite still working via shared memory, which after all, should still be a bottleneck. I can't quite believe that the results are so clear, so if you can think of any other effects that might cause them, please comment! Obviously, this benchmark isn't realistic because we're only measuring the overhead of the queue. Any real workload, even on a machine with 12 cores, would dwarf the overhead, and there'd be no point worrying about this effect. But would that be true on a machine with 100 cores? Still to be solved. The trouble is, you can't build many concurrent algorithms using only an SPSC queue to communicate. In particular, I can't see a way to build something as general purpose as actors on top of just SPSC queues. Fundamentally, an actor needs to be able to receive messages from multiple other actors, which seems to need an MPSC queue. I've been thinking about ways to build a sync-free MPSC queue out of multiple SPSC queues and some kind of sign-up mechanism. Hopefully I'll have something to tell you about soon, but leave a comment if you have any ideas.

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• Silverlight Cream for December 12, 2010 - 2 -- #1009

  - by Dave Campbell

  In this Issue: Michael Crump, Jesse Liberty, Shawn Wildermuth, Domagoj Pavlešic, Peter Kuhn, James Ashley, Sara Summers, Morten Nielsen, Peter Torr, and Tau Sick. Above the Fold: Silverlight: "Silverlight 4 – Coded UI Framework Video Tutorial" Michael Crump WP7: "Windows Phone From Scratch #12–Custom Behaviors (Part I)" Jesse Liberty From SilverlightCream.com: Silverlight 4 – Coded UI Framework Video Tutorial Michael Crump posted a video tutorial today on the Coded UI Test Framework that we got with the VS2010 Feature Pack 2. Wanna create automated tests? ... check out Michael's video and save yourself some time. Windows Phone From Scratch #12–Custom Behaviors (Part I) Jesse Liberty posted his Windows Phone from Scratch number 12 today... and it's on Custom Behaviors... cool stuff... need to read this and get your head around it... this is part 1, jump on it before he drops part 2 on us! The Next Application Platform? All of them... Shawn Wildermuth has a thought-provoking post up ... check it out and see if you're ready to join him on the adventure of building for all the platforms... Windows Phone 7 Accelerometer Test App Domagoj Pavlešic has a test app up for the accelerometer on the WP7 ... if you need to use it, and are having problems, a good example always helps me. Protocol of developing an animation texture tool Peter Kuhn found a need for a tool to creat some animations for an WP7 XNA game... so he challenged himself to write it, and detailed out all his steps as he went. Re-examining WP7 Launchers and Choosers James Ashley's most recent post is on the Pivot Control ... check this out... add a working Horizontally oriented slider to a pivot... plus some external links to help out New Prototyping Sketch Sheets for WP7 This is one of those posts that I had to go to SilverlightCream and make sure I hadn't hit it yet... pretty cool prototype sheets for WP7 by Sara Summers ... we've seen others, they're all good. Simulating GPS on Windows Phone 7 Morten Nielsen helps you get around the fact that you're not going to be able to use the emulator for testing your GPS app ... at least not without some assistance... and that doesn't mean hauling your dev system around your neighborhood, either. How to correctly handle application deactivation and reactivation We've seen posts on Tombstoning, but probably not from Silverlight team members... check this one out from Peter Torr ... great even sequence information and all the info on how to correctly handle it, plus external links to the documentation... you knew there was documentation, right? :) Localizing a Windows Phone 7 Application Tau Sick has a post up discussing Localization and your WP7 apps... coming from soneone with an app in the marketplace in 3 languages, it's a pretty good bet he's got it figured out! Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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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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• Use your iPhone or iPod Touch as a Boxee Remote

  - by DigitalGeekery

  Are you a Boxee user looking for a remote control solution? Well, you might not need to look any further than your pocket. The free Boxee Remote App turns your iPhone or iPod Touch into a a simple and easy-to-use Boxee remote. The Boxee Remote App works over WiFi, so there is no need for to buy or install additional hardware on your PC. Plus, you don’t even need to be within the line of sight for it to work. Using the Boxee Remote App Download the free Boxee Remote App from the App Store and install it on your iPhone or iPod Touch. See download link below. Next, make sure you have Boxee running on your PC. Select the Boxee icon to open the App.   The first time you log in you’ll be greeted by an introduction screen that will explain the two modes. Click Continue. When opened in “Button” mode, you’ll be presented with 4 directional buttons, an “OK” button, and a back arrow button that works like the Esc key does in Boxee. Button mode performs just as a normal remote. Touching the directional buttons moves your on screen selection right, left, up, and down. Tap the OK button to open or select an item. To enter “Gesture” mode, tap the Gesture button along the top of the Screen. Gesture mode works similar to a touch pad or trackball on a laptop. You drag the Boxee icon with your thumb or finger across the screen to move around within Boxee. The icon will turn red while being dragged or touched. Simply tap the icon to select.   The Settings button allows you to manually add or delete a host computer, or adjust the sensitivity of the controls.     If you need to enter text, such as enter logon credentials for an App, the on screen keyboard will pop up. While watching a video you’ll have on-screen Stop and Pause buttons along with a volume slider.   The Boxee Remote App is simple and easy to use. As long as you can connect via WiFi, you can use it to control any instance of Boxee running on any computer on your network. Download the Boxee Remote App Similar Articles Productive Geek Tips Why Wait? Amazing New Add-on Turns Your iPhone into an iPad! [Comic]Getting Started with BoxeeIntegrate Boxee with Media Center in Windows 7Watch Netflix Instant Movies in BoxeeWin a Free iPod Touch in the How-To Geek Facebook Giveaway! TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Out of band Security Update for Internet Explorer 7 Cool Looking Screensavers for Windows SyncToy syncs Files and Folders across Computers on a Network (or partitions on the same drive) If it were only this easy Classic Cinema Online offers 100’s of OnDemand Movies OutSync will Sync Photos of your Friends on Facebook and Outlook

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• InnoDB Compression Improvements in MySQL 5.6

  - by Inaam Rana

  MySQL 5.6 comes with significant improvements for the compression support inside InnoDB. The enhancements that we'll talk about in this piece are also a good example of community contributions. The work on these was conceived, implemented and contributed by the engineers at Facebook. Before we plunge into the details let us familiarize ourselves with some of the key concepts surrounding InnoDB compression. In InnoDB compressed pages are fixed size. Supported sizes are 1, 2, 4, 8 and 16K. The compressed page size is specified at table creation time. InnoDB uses zlib for compression. InnoDB buffer pool will attempt to cache compressed pages like normal pages. However, whenever a page is actively used by a transaction, we'll always have the uncompressed version of the page as well i.e.: we can have a page in the buffer pool in compressed only form or in a state where we have both the compressed page and uncompressed version but we'll never have a page in uncompressed only form. On-disk we'll always only have the compressed page. When both compressed and uncompressed images are present in the buffer pool they are always kept in sync i.e.: changes are applied to both atomically. Recompression happens when changes are made to the compressed data. In order to minimize recompressions InnoDB maintains a modification log within a compressed page. This is the extra space available in the page after compression and it is used to log modifications to the compressed data thus avoiding recompressions. DELETE (and ROLLBACK of DELETE) and purge can be performed without recompressing the page. This is because the delete-mark bit and the system fields DB_TRX_ID and DB_ROLL_PTR are stored in uncompressed format on the compressed page. A record can be purged by shuffling entries in the compressed page directory. This can also be useful for updates of indexed columns, because UPDATE of a key is mapped to INSERT+DELETE+purge. A compression failure happens when we attempt to recompress a page and it does not fit in the fixed size. In such case, we first try to reorganize the page and attempt to recompress and if that fails as well then we split the page into two and recompress both pages. Now lets talk about the three major improvements that we made in MySQL 5.6.Logging of Compressed Page Images:InnoDB used to log entire compressed data on the page to the redo logs when recompression happens. This was an extra safety measure to guard against the rare case where an attempt is made to do recovery using a different zlib version from the one that was used before the crash. Because recovery is a page level operation in InnoDB we have to be sure that all recompress attempts must succeed without causing a btree page split. However, writing entire compressed data images to the redo log files not only makes the operation heavy duty but can also adversely affect flushing activity. This happens because redo space is used in a circular fashion and when we generate much more than normal redo we fill up the space much more quickly and in order to reuse the redo space we have to flush the corresponding dirty pages from the buffer pool.Starting with MySQL 5.6 a new global configuration parameter innodb_log_compressed_pages. The default value is true which is same as the current behavior. If you are sure that you are not going to attempt to recover from a crash using a different version of zlib then you should set this parameter to false. This is a dynamic parameter.Compression Level:You can now set the compression level that zlib should choose to compress the data. The global parameter is innodb_compression_level - the default value is 6 (the zlib default) and allowed values are 1 to 9. Again the parameter is dynamic i.e.: you can change it on the fly.Dynamic Padding to Reduce Compression Failures:Compression failures are expensive in terms of CPU. We go through the hoops of recompress, failure, reorganize, recompress, failure and finally page split. At the same time, how often we encounter compression failure depends largely on the compressibility of the data. In MySQL 5.6, courtesy of Facebook engineers, we have an adaptive algorithm based on per-index statistics that we gather about compression operations. The idea is that if a certain index/table is experiencing too many compression failures then we should try to pack the 16K uncompressed version of the page less densely i.e.: we let some space in the 16K page go unused in an attempt that the recompression won't end up in a failure. In other words, we dynamically keep adding 'pad' to the 16K page till we get compression failures within an agreeable range. It works the other way as well, that is we'll keep removing the pad if failure rate is fairly low. To tune the padding effort two configuration variables are exposed. innodb_compression_failure_threshold_pct: default 5, range 0 - 100,dynamic, implies the percentage of compress ops to fail before we start using to padding. Value 0 has a special meaning of disabling the padding. innodb_compression_pad_pct_max: default 50, range 0 - 75, dynamic, the  maximum percentage of uncompressed data page that can be reserved as pad.

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• Take Snapshots of Your Favorite Movie Scenes in VLC

  - by DigitalGeekery

  Have you ever wanted to grab a screenshot of your favorite TV or movie scene? Today we’ll show you how to do so with VLC Media Player. If you don’t have it already, download and install the latest version of VLC (link below). Start playing your movie, and to grab a snapshot, select Video from the menu and click Snapshot.   When you take a snapshot, by default a preview is displayed at the top left and the folder where the file is saved is briefly displayed on the screen. If you enable the Advanced Controls, you can take a snapshot with a click of a button, and advance the video frame by frame to get a more accurate shot. To enable the Advanced Controls, select View and Advanced Controls.   You’ll see the Advanced Controls buttons appear below the slider. Now just click on the Snapshot button to grab an image.   You can more easily control the frame you wish to grab by pressing the Frame by Frame button. You can pause the movie when it is near the perfect spot for your snapshot, and then press the Frame by Frame button to advance a single frame at a time. By default, the snapshots are saved as PNG files in your My Pictures folder in Windows. You can change those setting in the Preferences. First, you’ll need to select All under Show settings at the bottom. Then click on Video on the left. Scroll down a bit and you’ll see the Snapshot section. Here you can change the format from PNG to JPG, change the directory to which the snapshots are stored, turn on and off the preview, and change the filename prefix. Click Save when finished.   Now you have nice screenshots of your favorite movie to display as you wish…such as a Desktop Background!   VLC is an excellent media player that runs on Windows, Mac, and Linux. In addition to playing almost any media file, it also makes grabbing screenshots of your videos a breeze. Want to know more about VLC? Check out some of our previous articles like how to rip DVDs and how to set a video as your desktop wallpaper. Download the Latest version of VLC Similar Articles Productive Geek Tips Desktop Fun: Rural Scenes WallpapersAutomatically Mount and View ISO files in Windows 7 Media CenterHow to Make/Edit a movie with Windows Movie Maker in Windows VistaAdd Images and Metadata to Windows 7 Media Center Movie LibraryQuickly Find Movies to Watch at Hello Movies TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 tinysong gives a shortened URL for you to post on Twitter (or anywhere) 10 Superb Firefox Wallpapers OpenDNS Guide Google TV The iPod Revolution Ultimate Boot CD can help when disaster strikes

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• Display is slightly blurry on (native) 1920x1080 resolution

  - by Martin Tuskevicius

  I have a computer monitor that is approximately 23" in size. Its native resolution is 1920x1080, and Windows 7 will not allow it to be any higher. However, I cannot make the resolution a little lower as well. When I right-click on my desktop and select 'Screen resolution,' the vertical slider has only two options: 1920x1080 and 1280x720. There are no real problems that I am having besides the fact that the image is slightly blurry. I can easily make things out and see them, but I definitely feel that the image is not as clear as it could be. My graphics card is ATI Radeon HD 5450 and it has the latest graphics drivers installed. I've tried playing around with the AMD VISION Engine Control Center to see if I can change an option to make the image clearer, but I had no luck. I did find one odd thing, though. When I lowered the refresh rate from 60Hz to 50Hz, the image kind of "zoomed in" but it also became perfectly clear like I would expect it to look. The problem is that when I use 50Hz, the image zooms in a little on the center and I lose maybe an inch and a half of the screen (I do not see the bar at the top of applications, I do not see the Windows taskbar thing, etc). I figured if I could somehow zoom in so that the entire image fills the screen (not the slightly cropped version) then I would have the perfectly crisp image of 50Hz, and also the uncropped image of 60Hz. However, upon zooming in, the image began to look blurry again just like it did with 60Hz. So I am at a loss here. I do not know how to make the image look as clear as it should. I have the latest drivers (I updated them today) and I know that my monitor supports the resolution that I am trying to use. Has anybody experienced something like this before? I'd really appreciate any input - thanks! Update: I have figured out how to make the display look crisp! I set it to the 50Hz option, and then I changed the scaling through the monitor itself, rather than software. Now, however, I am finding that games look pretty bad because since it is clear, the lower quality really becomes apparent. I cannot run new games at 1080p, so I run them at the lowest resolution possible (1280x720, since it is the only other option offered, as I have mentioned). So I am wondering, is there a way to have Windows display more resolution options?

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• Visual Studio build fails: unable to copy exe-file from obj\debug to bin\debug

  - by Nailuj

  This is a question asked before, both here on Stack Overflow and other places, but none of the suggestions I've found this far has helped me, so I just have to try asking a new question. Scenario: I have a simple Windows Forms application (C#, .NET 4.0, Visual Studio 2010). It has a couple of base forms that most other forms inherit from, it uses Entity Framework (and POCO classes) for database access. Nothing fancy, no multi-threading or anything. Problem: All was fine for a while. Then, all out of the blue, Visual Studio failed to build when I was about to launch the application. I got the warning "Unable to delete file '...bin\Debug\[ProjectName].exe'. Access to the path '...bin\Debug\[ProjectName].exe' is denied." and the error "Unable to copy file 'obj\x86\Debug\[ProjectName].exe' to 'bin\Debug\[ProjectName].exe'. The process cannot access the file 'bin\Debug\[ProjectName].exe' because it is being used by another process." (I get both the warning and the error when running Rebuild, but only the error when running Build - don't think that is relevant?) I understand perfectly fine what the warning and error message says: Visual Studio is obviously trying to overwrite the exe-file while it the same time has a lock on it for some reason. However, this doesn't help me find a solution to the problem... The only thing I've found working is to shut down Visual Studio and start it again. Building and launching then works, untill I make a change in some of the forms, then I have the same problem again and have to restart... Quite frustrating! As I mentioned above, this seems to be a known problem, so there are lots of suggested solutions. I'll just list what I've already tried here, so people know what to skip: Creating a new clean solution and just copy the files from the old solution. Adding the following to the following to the project's pre-build event: if exist "$(TargetPath).locked" del "$(TargetPath).locked"   if not exist "$(TargetPath).locked" if exist "$(TargetPath)" move "$(TargetPath)" "$(TargetPath).locked" Adding the following to the project properties (.csproj file): <GenerateResourceNeverLockTypeAssembliestrue</GenerateResourceNeverLockTypeAssemblies However, none of them worked for me, so you can probably see why I'm starting to get a bit frustrated. I don't know where else to look, so I hope somebody has something to give me! Is this a bug in VS, and if so is there a patch? Or has I done something wrong, do I have a circular reference or similar, and if so how could I find out? Any suggestions are highly appreciated :)

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• request response with activemq - always send double response.

  - by Chris Valley

  Hi, I'm new at activeMq. I tried to create a simple request response like this. public Listener(string destination) { // set factory ConnectionFactory factory = new ConnectionFactory(URL); IConnection connection; try { connection = factory.CreateConnection(); connection.Start(); ISession session = connection.CreateSession(); // create consumer for designated destination IMessageConsumer consumer = session.CreateConsumer(new Apache.NMS.ActiveMQ.Commands.ActiveMQQueue(destination)); consumer.Listener += new MessageListener(consumer_Listener); Console.ReadLine(); } catch (Exception ex) { Console.WriteLine(ex.ToString()); throw new Exception("Exception in Listening ", ex); } } The OnMessage static void consumer_Listener(IMessage message) { IConnectionFactory factory = new ConnectionFactory("tcp://localhost:61616/"); using (IConnection connection = factory.CreateConnection()) { //Create the Session using (ISession session = connection.CreateSession()) { //Create the Producer for the topic/queue // IMessageProducer prod = session.CreateProducer(new Apache.NMS.ActiveMQ.Commands.ActiveMQTempQueue(message.NMSDestination)); IMessageProducer producer = session.CreateProducer(message.NMSDestination); // Create Response // IMessage response = session.CreateMessage(); ITextMessage response = producer.CreateTextMessage("Replied from VS2010 Test"); //response.NMSReplyTo = new Apache.NMS.ActiveMQ.Commands.ActiveMQQueue("testQ1"); response.NMSCorrelationID = message.NMSCorrelationID; if (message.NMSReplyTo != null) { producer.Send(message.NMSReplyTo, response); Console.WriteLine("Receive: " + ((ITextMessage)message).NMSCorrelationID); Console.WriteLine("Received from : " + message.NMSDestination.ToString()); Console.WriteLine("----------------------------------------------------"); } } } } Every time i tried to send a request to the listener, the response always send repeatedly. The first response will have NMSReplyTo properties while the other not. My workaround to stop this situation by cheking the NMSReplyTo properties if (message.NMSReplyTo != null) { producer.Send(message.NMSReplyTo, response); Console.WriteLine("Receive: " + ((ITextMessage)message).NMSCorrelationID); Console.WriteLine("Received from : " + message.NMSDestination.ToString()); Console.WriteLine("----------------------------------------------------"); } In my understanding, this happened because there was a circular send response in the listener to the same Queue. Could you guys help me how to fix this? Many Thanks, Chris

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• Mixing policy-based design with CRTP in C++

  - by Eitan

  I'm attempting to write a policy-based host class (i.e., a class that inherits from its template class), with a twist, where the policy class is also templated by the host class, so that it can access its types. One example where this might be useful is where a policy (used like a mixin, really), augments the host class with a polymorphic clone() method. Here's a minimal example of what I'm trying to do: template <template <class> class P> struct Host : public P<Host<P> > { typedef P<Host<P> > Base; typedef Host* HostPtr; Host(const Base& p) : Base(p) {} }; template <class H> struct Policy { typedef typename H::HostPtr Hptr; Hptr clone() const { return Hptr(new H((Hptr)this)); } }; Policy<Host<Policy> > p; Host<Policy> h(p); int main() { return 0; } This, unfortunately, fails to compile, in what seems to me like circular type dependency: try.cpp: In instantiation of ‘Host<Policy>’: try.cpp:10: instantiated from ‘Policy<Host<Policy> >’ try.cpp:16: instantiated from here try.cpp:2: error: invalid use of incomplete type ‘struct Policy<Host<Policy> >’ try.cpp:9: error: declaration of ‘struct Policy<Host<Policy> >’ try.cpp: In constructor ‘Host<P>::Host(const P<Host<P> >&) [with P = Policy]’: try.cpp:17: instantiated from here try.cpp:5: error: type ‘Policy<Host<Policy> >’ is not a direct base of ‘Host<Policy>’ If anyone can spot an obvious mistake, or has successfuly mixing CRTP in policies, I would appreciate any help.

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• Flex barChart and XML Data

  - by theband

  <Projectlist> <Project> <ProjectName>Alcoswitch - ToggleSwitches </ProjectName> <ProjectStatusname>Planning</ProjectStatusname> </Project> <Project> <ProjectName> Transverse Wedge</ProjectName> <ProjectStatusname>Canceled</ProjectStatusname> </Project> <Project> <ProjectName>High Speed Pluggable I/O</ProjectName> <ProjectStatusname>In-Progress</ProjectStatusname> </Project> <Project> <ProjectName>"High Speed Pluggable I/O - Product Breakouts:</ProjectName> <ProjectStatusname>In-Progress</ProjectStatusname> </Project> <Project> <ProjectName>Circular Plastic Connector (CPC)</ProjectName> <ProjectStatusname>In-Progress</ProjectStatusname> </Project> </Projectlist> This is my XML data i am recieving, how can i show this in a bar chart. <mx:BarChart id="barChart" showDataTips="true" dataProvider="{ProjectStateInfo}" width="100%" height="100%"> <mx:horizontalAxis> <mx:CategoryAxis categoryField="ProjectStatusname"/> </mx:horizontalAxis> <mx:verticalAxis> <mx:CategoryAxis categoryField="ProjectName"/> </mx:verticalAxis> <mx:series> <mx:BarSeries id="barSeries" visible="true" yField="ProjectName" xField="ProjectStatusname" displayName="ProjectStatusname" /> </mx:series> </mx:BarChart> My X-Axis shows muliple values of In-Progress, but i just need one. Is it possible to represent such relationship using BarChart. Any other Flex chart is Advisable.

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• Oracle sample data problems

  - by Jay

  So, I have this java based data trasformation / masking tool, which I wanted to test out on Oracle 10g. The good part with Oracle 10g is that you get a load of sample schemas with half a million records in some. The schemas are : SH, OE, HR, IX and etc. So, I installed 10g, found out that the installation scripts are under ORACLE_HOME/demo/scripts. I customized these scripts a bit to run in batch mode. That solves one half of my requirement - to create source data for my testing my data transformation software. The second half of the requirement is that I create the same schemas under different names (TR_HR, TR_OE and so on...) without any data. These schemas would represent my target schemas. So, in short, my software would pick up data from a table in a schema and load it up in to the same table in a different schema. Now, I have two issues in creating my target schema and emptying it. I would like this in a batch job. But the oracle scripts you get, the sample schema names are not configurable. So, I tried creating a script, replacing OE with TR_OE, HR with TR_HR and so on. However, this approach is kind of irritating coz the sample schemas are kind of complicated in the way they are created; Oracle creates synonyms, views, materialized views, data types and lot of weird stuff. I would like the target schemas (TR_HR, TR_OE,...) to be empty. But some of the schemas have circular references, which would not allow me to delete data. The only work around seems to be removing certain foreign keys, deleting data and then adding the constraints back. Is there any easy way to all this, without all this fuss? I would need a complicated data set for my testing (complicated as in tables with triggers, multiple hierarchies.. for instance.. a child table that has children up to 5 levels, a parent table that refers to an IOT table and an IOT table that refers to a non-IOT table etc..). The sample schemas are just about perfect from a data set perspective. The only challenge I see is in automating this whole process of loading up the source schemas, and then creating the target schemas and emptying them. Appreciate your help and suggestions.

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• Write Scheme data structures so they can be eval-d back in, or alternative

  - by Jesse Millikan

  I'm writing an application (A juggling pattern animator) in PLT Scheme that accepts Scheme expressions as values for some fields. I'm attempting to write a small text editor that will let me "explode" expressions into expressions that can still be eval'd but contain the data as literals for manual tweaking. For example, (4hss->sexp "747") is a function call that generates a legitimate pattern. If I eval and print that, it becomes (((7 3) - - -) (- - (4 2) -) (- (7 2) - -) (- - - (7 1)) ((4 0) - - -) (- - (7 0) -) (- (7 2) - -) (- - - (4 3)) ((7 3) - - -) (- - (7 0) -) (- (4 1) - -) (- - - (7 1))) which can be "read" as a string, but will not "eval" the same as the function. For this statement, of course, what I need would be as simple as (quote (((7 3... but other examples are non-trivial. This one, for example, contains structs which print as vectors: pair-of-jugglers ; --> (#(struct:hand #(struct:position -0.35 2.0 1.0) #(struct:position -0.6 2.05 1.1) 1.832595714594046) #(struct:hand #(struct:position 0.35 2.0 1.0) #(struct:position 0.6 2.0500000000000003 1.1) 1.308996938995747) #(struct:hand #(struct:position 0.35 -2.0 1.0) #(struct:position 0.6 -2.05 1.1) -1.3089969389957472) #(struct:hand #(struct:position -0.35 -2.0 1.0) #(struct:position -0.6 -2.05 1.1) -1.8325957145940461)) I've thought of at least three possible solutions, none of which I like very much. Solution A is to write a recursive eval-able output function myself for a reasonably large subset of the values that I might be using. There (probably...) won't be any circular references by the nature of the data structures used, so that wouldn't be such a long job. The output would end up looking like `(((3 0) (... ; ex 1 `(,(make-hand (make-position ... ; ex 2 Or even worse if I could't figure out how to do it properly with quasiquoting. Solution B would be to write out everything as (read (open-input-string "(big-long-s-expression)")) which, technically, solves the problem I'm bringing up but is... ugly. Solution C might be a different approach of giving up eval and using only read for parsing input, or an uglier approach where the s-expression is used as directly data if eval fails, but those both seem unpleasant compared to using scheme values directly. Undiscovered Solution D would be a PLT Scheme option, function or library I haven't located that would match Solution A. Help me out before I start having bad recursion dreams again.

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• ASP.NET MVC 2 AJAX dilemma: Lose Models concept or create unmanageable JavaScript

  - by Slightly Frustrated

  Hi, Ok, let's assume we are working with ASP.NET MVC 2 (latest and greatest preview) and we want to create AJAX user interface with jQuery. So what are our real options here? Option 1 - Pass Json from the Controller to the view, and then the view submits Json back to the controller. This means (in the order given): User opens some View (let's say - /Invoices/January) which has to visualize a list of data (e.g. <IEnumerable<X.Y.Z.Models.Invoice>>) Controller retrieves the Model from the repository (assuming we are using repository pattern). Controller creates a new instance of a class which we will serialize to Json. The reasaon we do this, is because the model may not be serializable (circular reference ftl) Controller populates the soon-to-be-serialized class with data Controller serializes the class to Json and passes it the view. User does some change and submits the 'form' The View submits back Json to the controller The Controller now must 'manually' validate the input, because the Json passed does not bind to a Model See, if our View is communicating to the controller via Json, we lose the Model validation, which IMHO is incredible disadvantage. In this case, forget about data annotations and stuff. Option 2 - Ok, the alternative of the first approach is to pass the Models to the Views, which is the default behavior in the template when you start a new project. We pass a strong typed model to the view The view renders the appropriate html and javascript, sticking to the model property names. This is important! The user submits the form. If we stick to the model names, when we .serialize() the form and submit it to the controller it will map to a model. There is no Json mapping. The submitted form directly binds to a strongly typed model, hence, we can use the model validation. E.g. we keep the business logic where it should be. Problem with this approach is, if we refactor some of the Models (change property names, types, etc), the javascript we wrote would become invalid. We will have to manually refactor the scripting and hope we don't miss something. There is no way you can test it either. Ok, the question is - how to write an AJAX front end, which keeps the business logic validation in the model (e.g. controller passes and receives a Model type), but in the same time doesn't screw up the javascript and html when we refactor the model?

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• javascript simple object creation test: opera leaks?

  - by joe

  Hi, I am trying to figure out certain memory leak conditions in javascript on a few browsers. Currently I'm only testing FF 3.6, Opera 10.10, and Safari 4.0.3. I've started with a fairly simple test, and can confirm no memory leaks in Firefox and Safari. But Opera just takes memory and never gives it back. What gives? Here's the test: <html> <head> <script type="text/javascript"> window.onload = init; //window.onunload = cleanup; var a=[]; function init() { var d = document.createElement('div'); d.innerHTML = "page loading..."; document.body.appendChild(d); for (var i=0; i<400000; i++) { a[i] = new Obj("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"); } d.innerHTML = "PAGE LOADED"; } function cleanup() { for (var i=0; i<400000; i++) { a[i] = null; } } function Obj(msg) { this.msg=msg; } </script> </head> <body> </body> </html> I shouldn't need the cleanup() call on window.unload, but tried that also. No luck. As you can see this is simple JS, no circular DOM links, no closures. I monitor the memory usage using 'top' on Mac 10.4.11. Memory usage spikes up on page load, as expected. In FF and Safari reloading the page does not use any further memory, and all memory is returned when the window (tab) is closed. In Opera, memory spikes on load, and seems to also spike further on each reload (but not always...). But regardless of reload, memory never goes back down below the initial load spike. I had hoped this was a no-brainer test that all browsers would pass, so I could move on to more "interesting" conditions. Am I doing something wrong here? Or is this a known Opera issue? Thanks! -joe

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• How to perform duplicate key validation using entlib (or DataAnnotations), MVC, and Repository pattern

  - by olivehour

  I have a set of ASP.NET 4 projects that culminate in an MVC (3 RC2) app. The solution uses Unity and EntLib Validation for cross-cutting dependency injection and validation. Both are working great for injecting repository and service layer implementations. However, I can't figure out how to do duplicate key validation. For example, when a user registers, we want to make sure they don't pick a UserID that someone else is already using. For this type of validation, the validating object must have a repository reference... or some other way to get an IQueryable / IEnumerable reference to check against other rows already in the DB. What I have is a UserMetadata class that has all of the property setters and getters for a user, along with all of the appropriate DataAnnotations and EntLib Validation attributes. There is also a UserEntity class implemented using EF4 POCO Entity Generator templates. The UserEntity depends on UserMetadata, because it has a MetadataTypeAttribute. I also have a UserViewModel class that has the same exact MetadataType attribute. This way, I can apply the same validation rules, via attributes, to both the entity and viewmodel. There are no concrete references to the Repository classes whatsoever. All repositories are injected using Unity. There is also a service layer that gets dependency injection. In the MVC project, service layer implementation classes are injected into the Controller classes (the controller classes only contain service layer interface references). Unity then injects the Repository implementations into the service layer classes (service classes also only contain interface references). I've experimented with the DataAnnotations CustomValidationAttribute in the metadata class. The problem with this is the validation method must be static, and the method cannot instantiate a repository implementation directly. My repository interface is IRepository, and I have only one single repository implementation class defined as EntityRepository for all domain objects. To instantiate a repository explicitly I would need to say new EntityRepository(), which would result in a circular dependency graph: UserMetadata [depends on] DuplicateUserIDValidator [depends on] UserEntity [depends on] UserMetadata. I've also tried creating a custom EntLib Validator along with a custom validation attribute. Here I don't have the same problem with a static method. I think I could get this to work if I could just figure out how to make Unity inject my EntityRepository into the validator class... which I can't. Right now, all of the validation code is in my Metadata class library, since that's where the custom validation attribute would go. Any ideas on how to perform validations that need to check against the current repository state? Can Unity be used to inject a dependency into a lower-layer class library?

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• How to get colliding effect or bouncy when ball hits the track.

  - by Chandan Shetty SP

  I am using below formula to move the ball circular, where accelX and accelY are the values from accelerometer, it is working fine. But the problem in this code is mRadius (I fixed its value to 50), i need to change mRadius according to accelerometer values and also i need bouncing effect when it touches the track. Currently i am developing code by assuming only one ball is on the board. float degrees = -atan2(accelX, accelY) * 180 / 3.14159; int x = cCentrePoint.x + mRadius * cos(degreesToRadians(degrees)); int y = cCentrePoint.y + mRadius * sin(degreesToRadians(degrees)); Here is the snap of the game i want to develop: Updated: I am sending the updated code... mRadius = 5; mRange = NSMakeRange(0,60); -(void) updateBall: (UIAccelerationValue) accelX withY:(UIAccelerationValue)accelY { float degrees = -atan2(accelX, accelY) * 180 / 3.14159; int x = cCentrePoint.x + mRadius * cos(degreesToRadians(degrees)); int y = cCentrePoint.y + mRadius * sin(degreesToRadians(degrees)); //self.targetRect is rect of ball Object self.targetRect = CGRectMake(newX, newY, 8, 9); self.currentRect = self.targetRect; //http://books.google.co.in/books?id=WV9glgdrrrUC&pg=PA455#v=onepage&q=&f=false static NSDate *lastDrawTime; if(lastDrawTime!=nil) { NSTimeInterval secondsSinceLastDraw = -([lastDrawTime timeIntervalSinceNow]); ballXVelocity = ballXVelocity + (accelX * secondsSinceLastDraw) * [self isTouchedTrack:mRadius andRange:mRange]; ballYVelocity = ballYVelocity + -(accelY * secondsSinceLastDraw) * [self isTouchedTrack:mRadius andRange:mRange]; distXTravelled = distXTravelled + secondsSinceLastDraw * ballXVelocity * 50; distYTravelled = distYTravelled + secondsSinceLastDraw * ballYVelocity * 50; CGRect temp = self.targetRect; temp.origin.x += distXTravelled; temp.origin.y += distYTravelled; int radius = (temp.origin.x - cCentrePoint.x) / cos(degreesToRadians(degrees)); if( !NSLocationInRange(abs(radius),mRange)) { //Colided with the tracks...Need a better logic here ballXVelocity = -ballXVelocity; } else { // Need a better logic here self.targetRect = temp; } //NSLog(@"angle = %f",degrees); } [lastDrawTime release]; lastDrawTime = [ [NSDate alloc] init]; } In the above code i have initialized mRadius and mRange(indicate track) to some constant for testing, i am not getting the moving of the ball as i expected( bouncing effect when Collided with track ) with respect to accelerometer. Help me to recognize where i went wrong or send some code snippets or links which does the similar job. I am searching for better logic than my code, if you found share with me.

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• Property trigger in XAML for IsMouseOver fails to set Border.Background

  - by Mal Ross

  I'm currently trying to create a ControlTemplate for the Button class in WPF, replacing the usual visual tree with something that makes the button look similar to the little (X) close icon on Google Chrome's tabs. I decided to use a Path object in XAML to achieve the effect. Using a property trigger, the control responds to a change in the IsMouseOver property by setting the icon's red background. Here's the XAML from a test app: <Window x:Class="Widgets.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300"> <Window.Resources> <Style x:Key="borderStyle" TargetType="Border"> <Style.Triggers> <Trigger Property="IsMouseOver" Value="True"> <Setter Property="Background"> <Setter.Value> <SolidColorBrush Color="#CC0000"/> </Setter.Value> </Setter> </Trigger> </Style.Triggers> </Style> <ControlTemplate x:Key="closeButtonTemplate" TargetType="Button"> <Border Width="12" Height="12" CornerRadius="6" BorderBrush="#AAAAAA" Background="Transparent" Style="{StaticResource borderStyle}" ToolTip="Close"> <Viewbox Margin="2.75"> <Path Data="M 0,0 L 10,10 M 0,10 L 10,0" Stroke="{Binding BorderBrush, RelativeSource={RelativeSource FindAncestor, AncestorType=Border, AncestorLevel=1}}" StrokeThickness="1.8"/> </Viewbox> </Border> </ControlTemplate> </Window.Resources> <Grid Background="White"> <Button Template="{StaticResource closeButtonTemplate}"/> </Grid> </Window> Note that the circular background is always there - it's just transparent when the mouse isn't over it. The problem with this is that the trigger just isn't working. Nothing changes in the button's appearance. However, if I remove the Background="Transparent" value from the Border object in the ControlTemplate, the trigger does work (albeit only when over the 'X'). I really can't explain this. Setters for any other properties placed in the borderStyle resource work fine, but the Background setter fails as soon as the default background is specified in the ControlTemplate. Any ideas why it's happening and how I can fix it? I know I could easily replace this code with, for example, a .PNG-based image, but I want to understand why the current implementation isn't working. Thanks! :)

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• Data Annotations validation Built into model

  - by Josh

  I want to build an object model that automatically wires in validation when I attempt to save an object. I am using DataAnnotations for my validation, and it all works well, but I think my inheritance is whacked. I am looking here for some guidance on a better way to wire in my validation. So, to build in validation I have this interface public interface IValidatable { bool IsValid { get; } ValidationResponse ValidationResults { get; } void Validate(); } Then, I have a base class that all my objects inherit from. I did a class because I wanted to wire in the validation calls automatically. The issue is that the validation has to know the type of the class is it validating. So I use Generics like so. public class CoreObjectBase<T> : IValidatable where T : CoreObjectBase<T> { #region IValidatable Members public virtual bool IsValid { get { // First, check rules that always apply to this type var result = new Validator<T>().Validate((T)this); // return false if any violations occurred return !result.HasViolations; } } public virtual ValidationResponse ValidationResults { get { var result = new Validator<T>().Validate((T)this); return result; } } public virtual void Validate() { // First, check rules that always apply to this type var result = new Validator<T>().Validate((T)this); // throw error if any violations were detected if (result.HasViolations) throw new RulesException(result.Errors); } #endregion } So, I have this circular inheritance statement. My classes look like this then: public class MyClass : CoreObjectBase<MyClass> { } But the problem occurs when I have a more complicated model. Because I can only inherit from one class, when I have a situation where inheritance makes sense I believe the child classes won't have validation on their properties. public class Parent : CoreObjectBase<Parent> { //properties validated } public class Child : Parent { //properties not validated? } I haven't really tested the validation in these cases yet, but I am pretty sure that anything in child with a data annotation on it will not be automatically validated when I call Child.Validate(); due to the way the inheritance is configured. Is there a better way to do this?

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• Best WordPress Video Themes for a Video Blog

  - by Matt

  WordPress has made blogging so easy & fun, there are plenty of video blog themes that you can pick from. However there is always rarity in quality. We at JustSkins have gathered some high quality, tested, tried video themes list. We tried to find some WordPress themes for vloggers, we knew all along that there are very few yet some of them are just brilliant premium wordpress themes. More on that later, let’s find out some themes which you can install on your vlog right now. On Demand 2.0 A fully featured video WordPress premium theme from Press75. Includes  theme options panel for personal customization and content management options, post thumbnails, drop down navigation menu, custom widgets and lots more. Demo | Price: $75 | DOWNLOAD VideoZoom An outstanding premium WordPress video theme from WPZoom featuring standard video integration plus additionally it lets you play any video from all the popular video websites. VideoZoom theme also includes a featured video slider on the homepage, multiple post layout options, theme options panel, WordPress 3.0 menus, backgrounds etc. Demo | Price Single: $69, Developer: $149 | DOWNLOAD Vidley Press75′s easy to use premium WordPress video theme. This theme is full of great features, it can be a perfect choice if you intend to make it a portal someday..it is scalable to shape like a news portal or portfolios. The Theme is widget ready. It has ability to place Featured Content and Featured Category section on homepage. The drop down menus on this theme are nifty! Demo | Price $75 |  DOWNLOAD Live A video premium WordPress theme designed for streaming video, and live event broadcasting. You can embed live video broadcasts from third party services like Ustream etc, and features a prominent timer counting down to the next broadcast, rotating bumper images, Facebook and twitter integration for viewer interaction, theme admin options panel and more make this theme one of its kind. Demo | Price: $99, Support License: $149| DOWNLOAD Groovy Video Woo Themes is pioneer in making beautiful wordpress themes,  One such theme that is built by keeping the video blogger in mind. The Groovy Theme is very colourful video blog premium WordPress theme. Creating video posts is quick and easy with just a copy / paste of the video’s embed code. The theme enables automatic video resizing, plenty of widgets. Also allows you to pick color of your choice. Price: Single Use $70, Developer Price : $150 | DOWNLOAD Video Flick Another exciting Video blogging theme by Press75 is the Video Flick theme. Video Flick is compatible with any video service that provides embed code, or if you want to host your own videos, Video Flick is also compatible with FLV (Flash Video) and Quicktime formats. This theme allows you to either keep standard Blog and/or have Video posts. You can pick a light or dark color option. Demo | Price : $75 | DOWNLOAD Woo Tube An excellent video premium WordPress theme from Woothemes, the WooTube theme is a very easy video blog platform, as it comes with  automatic video resizing, a completely widgetised sidebar and 7 different colour schemes to choose from. The theme  has the ability to be used as a normal blog or a gallery. A very wise choice! Price: Single Use $70, Developer Price : $150 | DOWNLOAD eVid Theme One of the nicest WordPress theme designed specifically for the video bloggers. Simple to integrate videos from video hosts such as Youtube, Vimeo, Veoh, MetaCafe etc. Demo | Price: $19 | DOWNLOAD Tubular A video premium WordPress theme from StudioPress which can also be used as a used a simple website or a blog. The theme is also available in a light color version. Demo | Price: $59.95 | DOWNLOAD Video Elements 2.0 Another beautiful video premium WordPress theme from Press75. Video Elements 2.0 has been re-designed to include the features you need to easily run and maintain a video blog on WordPress. Demo | Price: $75 | DOWNLOAD TV Elements 3.0 The theme includes a featured video carousel on the homepage which can display any number of videos, a featured category section which displays up to 12 channels, creates automatic thumbnails and a lots more… Demo | Price: $75 | DOWNLOAD Wave A beautiful premium video wordpress theme, Flexible & Super cool looking. The Design has very earthy feel to it. The theme has featured video area & latest listing on the homepage. All in all a simple design no fancy features. Demo | Price: $35 | Download

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