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• First toe in the water with Object Databases : DB4O

  - by REA_ANDREW

  I have been wanting to have a play with Object Databases for a while now, and today I have done just that.  One of the obvious choices I had to make was which one to use.  My criteria for choosing one today was simple, I wanted one which I could literally wack in and start using, which means I wanted one which either had a .NET API or was designed/ported to .NET.  My decision was between two being: db4o MongoDb I went for db4o for the single reason that it looked like I could get it running and integrated the quickest.  I am making a Blogging application and front end as a project with which I can test and learn with these object databases.  Another requirement which I thought I would mention is that I also want to be able to use the said database in a shared hosting environment where I cannot install, run and maintain a server instance of said object database.  I can do exactly this with db4o. I have not tried to do this with MongoDb at time of writing.  There are quite a few in the industry now and you read an interesting post about different ones and how they are used with some of the heavy weights in the industry here : http://blog.marcua.net/post/442594842/notes-from-nosql-live-boston-2010 In the example which I am building I am using StructureMap as my IOC.  To inject the object for db4o I went with a Singleton instance scope as I am using a single file and I need this to be available to any thread on in the process as opposed to using the server implementation where I could open and close client connections with the server handling each one respectively.  Again I want to point out that I have chosen to stick with the non server implementation of db4o as I wanted to use this in a shared hosting environment where I cannot have such servers installed and run.     public static class Bootstrapper    {        public static void ConfigureStructureMap()        {            ObjectFactory.Initialize(x => x.AddRegistry(new MyApplicationRegistry()));        }    }    public class MyApplicationRegistry : Registry    {        public const string DB4O_FILENAME = "blog123";        public string DbPath        {            get            {                return Path.Combine(Path.GetDirectoryName(Assembly.GetAssembly(typeof(IBlogRepository)).Location), DB4O_FILENAME);            }        }        public MyApplicationRegistry()        {            For<IObjectContainer>().Singleton().Use(                () => Db4oEmbedded.OpenFile(Db4oEmbedded.NewConfiguration(), DbPath));            Scan(assemblyScanner =>            {                assemblyScanner.TheCallingAssembly();                assemblyScanner.WithDefaultConventions();            });        }    } So my code above is the structure map plumbing which I use for the application.  I am doing this simply as a quick scratch pad to play around with different things so I am simply segregating logical layers with folder structure as opposed to different assemblies.  It will be easy if I want to do this with any segment but for the purposes of example I have literally just wacked everything in the one assembly.  You can see an example file structure I have on the right.  I am planning on testing out a few implementations of the object databases out there so I can program to an interface of IBlogRepository One of the things which I was unsure about was how it performed under a multi threaded environment which it will undoubtedly be used 9 times out of 10, and for the reason that I am using the db context as a singleton, I assumed that the library was of course thread safe but I did not know as I have not read any where in the documentation, again this is probably me not reading things correctly.  In short though I threw together a simple test where I simply iterate to a limit each time kicking a common task off with a thread from a thread pool.  This task simply created and added an random Post and added it to the storage. The execution of the threads I put inside the Setup of the Test and then simply ensure the number of posts committed to the database is equal to the number of iterations I made; here is the code I used to do the multi thread jobs: [TestInitialize] public void Setup() { var sw = new System.Diagnostics.Stopwatch(); sw.Start(); var resetEvent = new ManualResetEvent(false); ThreadPool.SetMaxThreads(20, 20); for (var i = 0; i < MAX_ITERATIONS; i++) { ThreadPool.QueueUserWorkItem(delegate(object state) { var eventToReset = (ManualResetEvent)state; var post = new Post { Author = MockUser, Content = "Mock Content", Title = "Title" }; Repository.Put(post); var counter = Interlocked.Decrement(ref _threadCounter); if (counter == 0) eventToReset.Set(); }, resetEvent); } WaitHandle.WaitAll(new[] { resetEvent }); sw.Stop(); Console.WriteLine("{0:00}.{1:00} seconds", sw.Elapsed.Seconds, sw.Elapsed.Milliseconds); }   I was not doing this to test out the speed performance of db4o but while I was doing this I could not help but put in a StopWatch and see out of sheer interest how fast it would take to insert a number of Posts.  I tested it out in this case with 10000 inserts of a small, simple POCO and it resulted in an average of:  899.36 object inserts / second.  Again this is just  simple crude test which came out of my curiosity at how it performed under many threads when using the non server implementation of db4o. The spec summary of the computer I used is as follows: With regards to the actual Repository implementation itself, it really is quite straight forward and I have to say I am very surprised at how easy it was to integrate and get up and running.  One thing I have noticed in the exposure I have had so far is that the Query returns IList<T> as opposed to IQueryable<T> but again I have not looked into this in depth and this could be there already and if not they have provided everything one needs to make there own repository.  An example of a couple of methods from by db4o implementation of the BlogRepository is below: public class BlogRepository : IBlogRepository { private readonly IObjectContainer _db; public BlogRepository(IObjectContainer db) { _db = db; } public void Put(DomainObject obj) { _db.Store(obj); } public void Delete(DomainObject obj) { _db.Delete(obj); } public Post GetByKey(object key) { return _db.Query<Post>(post => post.Key == key).FirstOrDefault(); } … Anyways I hope to get a few more implementations going of the object databases and literally just get familiarized with them and the concept of no sql databases. Cheers for now, Andrew

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• C#/.NET &ndash; Finding an Item&rsquo;s Index in IEnumerable&lt;T&gt;

  - by James Michael Hare

  Sorry for the long blogging hiatus.  First it was, of course, the holidays hustle and bustle, then my brother and his wife gave birth to their son, so I’ve been away from my blogging for two weeks. Background: Finding an item’s index in List<T> is easy… Many times in our day to day programming activities, we want to find the index of an item in a collection.  Now, if we have a List<T> and we’re looking for the item itself this is trivial: 1: // assume have a list of ints: 2: var list = new List<int> { 1, 13, 42, 64, 121, 77, 5, 99, 132 }; 3:  4: // can find the exact item using IndexOf() 5: var pos = list.IndexOf(64); This will return the position of the item if it’s found, or –1 if not.  It’s easy to see how this works for primitive types where equality is well defined.  For complex types, however, it will attempt to compare them using EqualityComparer<T>.Default which, in a nutshell, relies on the object’s Equals() method. So what if we want to search for a condition instead of equality?  That’s also easy in a List<T> with the FindIndex() method: 1: // assume have a list of ints: 2: var list = new List<int> { 1, 13, 42, 64, 121, 77, 5, 99, 132 }; 3:  4: // finds index of first even number or -1 if not found. 5: var pos = list.FindIndex(i => i % 2 == 0);   Problem: Finding an item’s index in IEnumerable<T> is not so easy... This is all well and good for lists, but what if we want to do the same thing for IEnumerable<T>?  A collection of IEnumerable<T> has no indexing, so there’s no direct method to find an item’s index.  LINQ, as powerful as it is, gives us many tools to get us this information, but not in one step.  As with almost any problem involving collections, there are several ways to accomplish the same goal.  And once again as with almost any problem involving collections, the choice of the solution somewhat depends on the situation. So let’s look at a few possible alternatives.  I’m going to express each of these as extension methods for simplicity and consistency. Solution: The TakeWhile() and Count() combo One of the things you can do is to perform a TakeWhile() on the list as long as your find condition is not true, and then do a Count() of the items it took.  The only downside to this method is that if the item is not in the list, the index will be the full Count() of items, and not –1.  So if you don’t know the size of the list beforehand, this can be confusing. 1: // a collection of extra extension methods off IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // Finds an item in the collection, similar to List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: // note if item not found, result is length and not -1! 8: return list.TakeWhile(i => !finder(i)).Count(); 9: } 10: } Personally, I don’t like switching the paradigm of not found away from –1, so this is one of my least favorites.  Solution: Select with index Many people don’t realize that there is an alternative form of the LINQ Select() method that will provide you an index of the item being selected: 1: list.Select( (item,index) => do something here with the item and/or index... ) This can come in handy, but must be treated with care.  This is because the index provided is only as pertains to the result of previous operations (if any).  For example: 1: // assume have a list of ints: 2: var list = new List<int> { 1, 13, 42, 64, 121, 77, 5, 99, 132 }; 3:  4: // you'd hope this would give you the indexes of the even numbers 5: // which would be 2, 3, 8, but in reality it gives you 0, 1, 2 6: list.Where(item => item % 2 == 0).Select((item,index) => index); The reason the example gives you the collection { 0, 1, 2 } is because the where clause passes over any items that are odd, and therefore only the even items are given to the select and only they are given indexes. Conversely, we can’t select the index and then test the item in a Where() clause, because then the Where() clause would be operating on the index and not the item! So, what we have to do is to select the item and index and put them together in an anonymous type.  It looks ugly, but it works: 1: // extensions defined on IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // finds an item in a collection, similar to List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: // if you don't name the anonymous properties they are the variable names 8: return list.Select((item, index) => new { item, index }) 9: .Where(p => finder(p.item)) 10: .Select(p => p.index + 1) 11: .FirstOrDefault() - 1; 12: } 13: }     So let’s look at this, because i know it’s convoluted: First Select() joins the items and their indexes into an anonymous type. Where() filters that list to only the ones matching the predicate. Second Select() picks the index of the matches and adds 1 – this is to distinguish between not found and first item. FirstOrDefault() returns the first item found from the previous clauses or default (zero) if not found. Subtract one so that not found (zero) will be –1, and first item (one) will be zero. The bad thing is, this is ugly as hell and creates anonymous objects for each item tested until it finds the match.  This concerns me a bit but we’ll defer judgment until compare the relative performances below. Solution: Convert ToList() and use FindIndex() This solution is easy enough.  We know any IEnumerable<T> can be converted to List<T> using the LINQ extension method ToList(), so we can easily convert the collection to a list and then just use the FindIndex() method baked into List<T>. 1: // a collection of extension methods for IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // find the index of an item in the collection similar to List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: return list.ToList().FindIndex(finder); 8: } 9: } This solution is simplicity itself!  It is very concise and elegant and you need not worry about anyone misinterpreting what it’s trying to do (as opposed to the more convoluted LINQ methods above). But the main thing I’m concerned about here is the performance hit to allocate the List<T> in the ToList() call, but once again we’ll explore that in a second. Solution: Roll your own FindIndex() for IEnumerable<T> Of course, you can always roll your own FindIndex() method for IEnumerable<T>.  It would be a very simple for loop which scans for the item and counts as it goes.  There’s many ways to do this, but one such way might look like: 1: // extension methods for IEnumerable<T> 2: public static class EnumerableExtensions 3: { 4: // Finds an item matching a predicate in the enumeration, much like List<T>.FindIndex() 5: public static int FindIndex<T>(this IEnumerable<T> list, Predicate<T> finder) 6: { 7: int index = 0; 8: foreach (var item in list) 9: { 10: if (finder(item)) 11: { 12: return index; 13: } 14:  15: index++; 16: } 17:  18: return -1; 19: } 20: } Well, it’s not quite simplicity, and those less familiar with LINQ may prefer it since it doesn’t include all of the lambdas and behind the scenes iterators that come with deferred execution.  But does having this long, blown out method really gain us much in performance? Comparison of Proposed Solutions So we’ve now seen four solutions, let’s analyze their collective performance.  I took each of the four methods described above and run them over 100,000 iterations of lists of size 10, 100, 1000, and 10000 and here’s the performance results.  Then I looked for targets at the begining of the list (best case), middle of the list (the average case) and not in the list (worst case as must scan all of the list). Each of the times below is the average time in milliseconds for one execution as computer over the 100,000 iterations: Searches Matching First Item (Best Case)   10 100 1000 10000 TakeWhile 0.0003 0.0003 0.0003 0.0003 Select 0.0005 0.0005 0.0005 0.0005 ToList 0.0002 0.0003 0.0013 0.0121 Manual 0.0001 0.0001 0.0001 0.0001   Searches Matching Middle Item (Average Case)   10 100 1000 10000 TakeWhile 0.0004 0.0020 0.0191 0.1889 Select 0.0008 0.0042 0.0387 0.3802 ToList 0.0002 0.0007 0.0057 0.0562 Manual 0.0002 0.0013 0.0129 0.1255   Searches Where Not Found (Worst Case)   10 100 1000 10000 TakeWhile 0.0006 0.0039 0.0381 0.3770 Select 0.0012 0.0081 0.0758 0.7583 ToList 0.0002 0.0012 0.0100 0.0996 Manual 0.0003 0.0026 0.0253 0.2514   Notice something interesting here, you’d think the “roll your own” loop would be the most efficient, but it only wins when the item is first (or very close to it) regardless of list size.  In almost all other cases though and in particular the average case and worst case, the ToList()/FindIndex() combo wins for performance, even though it is creating some temporary memory to hold the List<T>.  If you examine the algorithm, the reason why is most likely because once it’s in a ToList() form, internally FindIndex() scans the internal array which is much more efficient to iterate over.  Thus, it takes a one time performance hit (not including any GC impact) to create the List<T> but after that the performance is much better. Summary If you’re concerned about too many throw-away objects, you can always roll your own FindIndex() method, but for sheer simplicity and overall performance, using the ToList()/FindIndex() combo performs best on nearly all list sizes in the average and worst cases.    Technorati Tags: C#,.NET,Litte Wonders,BlackRabbitCoder,Software,LINQ,List

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• How to implement jquery and Mootools together ?

  - by Avi Kumar Manku

  I am developing a website in which I am implementing two slider for images gallery using one with jQuery and one with moottools. But there is problem in implementing these because when I use both together the jQuery slider doesn't works where mootools slider works. jQuery slider works in case where I remove mootools. What should I do to implement both sliders together? Any suggestions will be helpful. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Tresmode | Footwear &amp; Accessories</title> <script type="text/javascript" src="js/jquery-1.5.min.js"></script> <script src="js/jquery.easing.1.3.js" type="text/javascript"></script> <script src="js/jquery.slideviewer.1.2.js" type="text/javascript"></script> <!-- Syntax hl --> <script src="js/jquery.syntax.min.js" type="text/javascript" charset="utf-8"></script> <script type="text/javascript"> $(window).bind("load", function() { $("div#mygaltop").slideView({toolTip: true, ttOpacity: 0.5}); $("div#mygalone").slideView(); //if leaved blank performs the default kind of animation (easeInOutExpo, 750) $("div#mygaltwo").slideView({ easeFunc: "easeInOutBounce", easeTime: 2200, toolTip: true }); $("div#mygalthree").slideView({ easeFunc: "easeInOutSine", easeTime: 100, uiBefore: true, ttOpacity: 0.5, toolTip: true }); }); $(function(){ $.syntax({root: 'http://www.gcmingati.net/wordpress/wp-content/themes/giancarlo-mingati/js/jquery-syntax/'}); }); </script> <link href="css/style.css" rel="stylesheet" type="text/css" /> <link href="css/product.css" rel="stylesheet" type="text/css" /> <link href="css/scroll.css" rel="stylesheet" type="text/css" /> <!--[if lte IE 8]> <link href="css/ieonly.css" rel="stylesheet" type="text/css" /> <![endif]--> <script language="javascript" type="text/javascript" src="js/mootools-1.2-core.js"></script> <script language="javascript" type="text/javascript" src="js/mootools-1.2-more.js"></script> <script language="javascript" type="text/javascript" src="js/SlideItMoo.js"></script> <script language="javascript" type="text/javascript"> window.addEvent('domready', function(){ /* thumbnails example , links only */ new SlideItMoo({itemsVisible:5, // the number of thumbnails that are visible currentElement: 0, // the current element. starts from 0. If you want to start the display with a specific thumbnail, change this thumbsContainer: 'thumbs', elementScrolled: 'thumb_container', overallContainer: 'gallery_container'}); /* thumbnails example , div containers */ new SlideItMoo({itemsVisible:5, // the number of thumbnails that are visible currentElement: 0, // the current element. starts from 0. If you want to start the display with a specific thumbnail, change this thumbsContainer: 'thumbs2', elementScrolled: 'thumb_container2', overallContainer: 'gallery_container2'}); /* banner rotator example */ new SlideItMoo({itemsVisible:1, // the number of thumbnails that are visible showControls:0, // show the next-previous buttons autoSlide:2500, // insert interval in milliseconds currentElement: 0, // the current element. starts from 0. If you want to start the display with a specific thumbnail, change this transition: Fx.Transitions.Bounce.easeOut, thumbsContainer: 'banners', elementScrolled: 'banner_container', overallContainer: 'banners_container'}); }); </script> </head> <body> <div id="landing"> <!-- landing page menu --> <div id="landing_menu"> <ul> <li><a class="active" href="#">SPECIALS</a></li> <li><a href="#">SHOP MEN'S</a></li> <li class="none"><a class="none" href="#">SHOP WOMEN'S</a></li> </ul> </div> <!-- landing page menu --> <!-- loading container menu --> <div id="container_part"> <div id="big_image_slider"> <!-- <img src="images/briteloves.png" alt="Britelove" /> --> <div id="mygaltop" class="svw"> <ul> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/briteloves.png" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/1.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/2.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/3.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/4.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/5.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/6.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/7.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/8.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/9.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/10.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/11.jpg" /></li> <li><img alt="Tresmode | Footwear &amp; Accessories" src="images/12.jpg" /></li> </ul> </div> </div> <div class="new_style_banner"><img src="images/new_styles.png" alt="new style" /></div> <div class="new_style_banner"><img src="images/ford-super-models.png" alt="ford super models" /></div> </div> <!--- loading container menu --> <!-- footer scrool ---> <div id="footer_scroll"> <!--thumbnails slideshow begin--> <div id="gallery_container"> <div id="thumb_container"> <div id="thumbs"> <a href="gallery/full/DC080302018.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/1.jpg"/></a> <a href="gallery/full/DC080302028.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/2.jpg" /></a> <a href="gallery/full/DC080302030.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/3.jpg"/></a> <a href="gallery/full/DC080302018.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/4.jpg" /></a> <a href="gallery/full/DC080302028.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/5.jpg" /></a> <a href="gallery/full/DC080302030.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/6.jpg"/></a> <a href="gallery/full/DC080302018.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/1.jpg"/></a> <a href="gallery/full/DC080302028.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/2.jpg" /></a> <a href="gallery/full/DC080302030.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/7.jpg"/></a> <a href="gallery/full/DC080302018.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/8.jpg" /></a> <a href="gallery/full/DC080302028.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/9.jpg" /></a> <a href="gallery/full/DC080302030.jpg" rel="lightbox[galerie]" target="_blank"><img src="gallery/thumb/10.jpg"/></a> </div> </div> </div> <!--thumbnails slideshow end--> </div> <!-- foooter scrooll --> </div> <script type="text/javascript"> var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); </script> <script type="text/javascript"> var pageTracker = _gat._getTracker("UA-2064812-2"); pageTracker._initData(); pageTracker._trackPageview(); </script> </body> </html>

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• jQuery CSS Property Monitoring Plug-in updated

  - by Rick Strahl

  A few weeks back I had talked about the need to watch properties of an object and be able to take action when certain values changed. The need for this arose out of wanting to build generic components that could 'attach' themselves to other objects. One example is a drop shadow - if I add a shadow behavior to an object I want the shadow to be pinned to that object so when that object moves I also want the shadow to move with it, or when the panel is hidden the shadow should hide with it - automatically without having to explicitly hook up monitoring code to the panel. For example, in my shadow plug-in I can now do something like this (where el is the element that has the shadow attached and sh is the shadow): if (!exists) // if shadow was created el.watch("left,top,width,height,display", function() { if (el.is(":visible")) $(this).shadow(opt); // redraw else sh.hide(); }, 100, "_shadowMove"); The code now monitors several properties and if any of them change the provided function is called. So when the target object is moved or hidden or resized the watcher function is called and the shadow can be redrawn or hidden in the case of visibility going away. So if you run any of the following code: $("#box") .shadow() .draggable({ handle: ".blockheader" }); // drag around the box - shadow should follow // hide the box - shadow should disappear with box setTimeout(function() { $("#box").hide(); }, 4000); // show the box - shadow should come back too setTimeout(function() { $("#box").show(); }, 8000); This can be very handy functionality when you're dealing with objects or operations that you need to track generically and there are no native events for them. For example, with a generic shadow object that attaches itself to any another element there's no way that I know of to track whether the object has been moved or hidden either via some UI operation (like dragging) or via code. While some UI operations like jQuery.ui.draggable would allow events to fire when the mouse is moved nothing of the sort exists if you modify locations in code. Even tracking the object in drag mode this is hardly generic behavior - a generic shadow implementation can't know when dragging is hooked up. So the watcher provides an alternative that basically gives an Observer like pattern that notifies you when something you're interested in changes. In the watcher hookup code (in the shadow() plugin) above  a check is made if the object is visible and if it is the shadow is redrawn. Otherwise the shadow is hidden. The first parameter is a list of CSS properties to be monitored followed by the function that is called. The function called receives this as the element that's been changed and receives two parameters: The array of watched objects with their current values, plus an index to the object that caused the change function to fire. How does it work When I wrote it about this last time I started out with a simple timer that would poll for changes at a fixed interval with setInterval(). A few folks commented that there are is a DOM API - DOMAttrmodified in Mozilla and propertychange in IE that allow notification whenever any property changes which is much more efficient and smooth than the setInterval approach I used previously. On browser that support these events (FireFox and IE basically - WebKit has the DOMAttrModified event but it doesn't appear to work) the shadow effect is instant - no 'drag behind' of the shadow. Running on a browser that doesn't support still uses setInterval() and the shadow movement is slightly delayed which looks sloppy. There are a few additional changes to this code - it also supports monitoring multiple CSS properties now so a single object can monitor a host of CSS properties rather than one object per property which is easier to work with. For display purposes position, bounds and visibility will be common properties that are to be watched. Here's what the new version looks like: $.fn.watch = function (props, func, interval, id) { /// <summary> /// Allows you to monitor changes in a specific /// CSS property of an element by polling the value. /// when the value changes a function is called. /// The function called is called in the context /// of the selected element (ie. this) /// </summary> /// <param name="prop" type="String">CSS Properties to watch sep. by commas</param> /// <param name="func" type="Function"> /// Function called when the value has changed. /// </param> /// <param name="interval" type="Number"> /// Optional interval for browsers that don't support DOMAttrModified or propertychange events. /// Determines the interval used for setInterval calls. /// </param> /// <param name="id" type="String">A unique ID that identifies this watch instance on this element</param> /// <returns type="jQuery" /> if (!interval) interval = 200; if (!id) id = "_watcher"; return this.each(function () { var _t = this; var el$ = $(this); var fnc = function () { __watcher.call(_t, id) }; var itId = null; var data = { id: id, props: props.split(","), func: func, vals: [props.split(",").length], fnc: fnc, origProps: props, interval: interval }; $.each(data.props, function (i) { data.vals[i] = el$.css(data.props[i]); }); el$.data(id, data); hookChange(el$, id, data.fnc); }); function hookChange(el$, id, fnc) { el$.each(function () { var el = $(this); if (typeof (el.get(0).onpropertychange) == "object") el.bind("propertychange." + id, fnc); else if ($.browser.mozilla) el.bind("DOMAttrModified." + id, fnc); else itId = setInterval(fnc, interval); }); } function __watcher(id) { var el$ = $(this); var w = el$.data(id); if (!w) return; var _t = this; if (!w.func) return; // must unbind or else unwanted recursion may occur el$.unwatch(id); var changed = false; var i = 0; for (i; i < w.props.length; i++) { var newVal = el$.css(w.props[i]); if (w.vals[i] != newVal) { w.vals[i] = newVal; changed = true; break; } } if (changed) w.func.call(_t, w, i); // rebind event hookChange(el$, id, w.fnc); } } $.fn.unwatch = function (id) { this.each(function () { var el = $(this); var fnc = el.data(id).fnc; try { if (typeof (this.onpropertychange) == "object") el.unbind("propertychange." + id, fnc); else if ($.browser.mozilla) el.unbind("DOMAttrModified." + id, fnc); else clearInterval(id); } // ignore if element was already unbound catch (e) { } }); return this; } There are basically two jQuery functions - watch and unwatch. jQuery.fn.watch(props,func,interval,id) Starts watching an element for changes in the properties specified. props The CSS properties that are to be watched for changes. If any of the specified properties changes the function specified in the second parameter is fired. func (watchData,index) The function fired in response to a changed property. Receives this as the element changed and object that represents the watched properties and their respective values. The first parameter is passed in this structure:    { id: itId, props: [], func: func, vals: [] }; A second parameter is the index of the changed property so data.props[i] or data.vals[i] gets the property value that has changed. interval The interval for setInterval() for those browsers that don't support property watching in the DOM. In milliseconds. id An optional id that identifies this watcher. Required only if multiple watchers might be hooked up to the same element. The default is _watcher if not specified. jQuery.fn.unwatch(id) Unhooks watching of the element by disconnecting the event handlers. id Optional watcher id that was specified in the call to watch. This value can be omitted to use the default value of _watcher. You can also grab the latest version of the  code for this plug-in as well as the shadow in the full library at: http://www.west-wind.com:8080/svn/jquery/trunk/jQueryControls/Resources/ww.jquery.js watcher has no other dependencies although it lives in this larger library. The shadow plug-in depends on watcher.© Rick Strahl, West Wind Technologies, 2005-2011

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• Windows Phone 7 : Dragging and flicking UI controls

  - by TechTwaddle

  Who would want to flick and drag UI controls!? There might not be many use cases but I think some concepts here are worthy of a post. So we will create a simple silverlight application for windows phone 7, containing a canvas element on which we’ll place a button control and an image and then, as the title says, drag and flick the controls. Here’s Mainpage.xaml, <Grid x:Name="LayoutRoot" Background="Transparent">   <Grid.RowDefinitions>     <RowDefinition Height="Auto"/>     <RowDefinition Height="*"/>   </Grid.RowDefinitions>     <!--TitlePanel contains the name of the application and page title-->   <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">     <TextBlock x:Name="ApplicationTitle" Text="KINETICS" Style="{StaticResource PhoneTextNormalStyle}"/>     <TextBlock x:Name="PageTitle" Text="drag and flick" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>   </StackPanel>     <!--ContentPanel - place additional content here-->   <Grid x:Name="ContentPanel" Grid.Row="1" >     <Canvas x:Name="MainCanvas" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">       <Canvas.Background>         <LinearGradientBrush StartPoint="0 0" EndPoint="0 1">           <GradientStop Offset="0" Color="Black"/>           <GradientStop Offset="1.5" Color="BlanchedAlmond"/>         </LinearGradientBrush>       </Canvas.Background>     </Canvas>   </Grid> </Grid> the second row in the main grid contains a canvas element, MainCanvas, with its horizontal and vertical alignment set to stretch so that it occupies the entire grid. The canvas background is a linear gradient brush starting with Black and ending with BlanchedAlmond. We’ll add the button and image control to this canvas at run time. Moving to Mainpage.xaml.cs the Mainpage class contains the following members, public partial class MainPage : PhoneApplicationPage {     Button FlickButton;     Image FlickImage;       FrameworkElement ElemToMove = null;     double ElemVelX, ElemVelY;       const double SPEED_FACTOR = 60;       DispatcherTimer timer; FlickButton and FlickImage are the controls that we’ll add to the canvas. ElemToMove, ElemVelX and ElemVelY will be used by the timer callback to move the ui control. SPEED_FACTOR is used to scale the velocities of ui controls. Here’s the Mainpage constructor, // Constructor public MainPage() {     InitializeComponent();       AddButtonToCanvas();       AddImageToCanvas();       timer = new DispatcherTimer();     timer.Interval = TimeSpan.FromMilliseconds(35);     timer.Tick += new EventHandler(OnTimerTick); } We’ll look at those AddButton and AddImage functions in a moment. The constructor initializes a timer which fires every 35 milliseconds, this timer will be started after the flick gesture completes with some inertia. Back to AddButton and AddImage functions, void AddButtonToCanvas() {     LinearGradientBrush brush;     GradientStop stop1, stop2;       Random rand = new Random(DateTime.Now.Millisecond);       FlickButton = new Button();     FlickButton.Content = "";     FlickButton.Width = 100;     FlickButton.Height = 100;       brush = new LinearGradientBrush();     brush.StartPoint = new Point(0, 0);     brush.EndPoint = new Point(0, 1);       stop1 = new GradientStop();     stop1.Offset = 0;     stop1.Color = Colors.White;       stop2 = new GradientStop();     stop2.Offset = 1;     stop2.Color = (Application.Current.Resources["PhoneAccentBrush"] as SolidColorBrush).Color;       brush.GradientStops.Add(stop1);     brush.GradientStops.Add(stop2);       FlickButton.Background = brush;       Canvas.SetTop(FlickButton, rand.Next(0, 400));     Canvas.SetLeft(FlickButton, rand.Next(0, 200));       MainCanvas.Children.Add(FlickButton);       //subscribe to events     FlickButton.ManipulationDelta += new EventHandler<ManipulationDeltaEventArgs>(OnManipulationDelta);     FlickButton.ManipulationCompleted += new EventHandler<ManipulationCompletedEventArgs>(OnManipulationCompleted); } this function is basically glorifying a simple task. After creating the button and setting its height and width, its background is set to a linear gradient brush. The direction of the gradient is from top towards bottom and notice that the second stop color is the PhoneAccentColor, which changes along with the theme of the device. The line,     stop2.Color = (Application.Current.Resources["PhoneAccentBrush"] as SolidColorBrush).Color; does the magic of extracting the PhoneAccentBrush from application’s resources, getting its color and assigning it to the gradient stop. AddImage function is straight forward in comparison, void AddImageToCanvas() {     Random rand = new Random(DateTime.Now.Millisecond);       FlickImage = new Image();     FlickImage.Source = new BitmapImage(new Uri("/images/Marble.png", UriKind.Relative));       Canvas.SetTop(FlickImage, rand.Next(0, 400));     Canvas.SetLeft(FlickImage, rand.Next(0, 200));       MainCanvas.Children.Add(FlickImage);       //subscribe to events     FlickImage.ManipulationDelta += new EventHandler<ManipulationDeltaEventArgs>(OnManipulationDelta);     FlickImage.ManipulationCompleted += new EventHandler<ManipulationCompletedEventArgs>(OnManipulationCompleted); } The ManipulationDelta and ManipulationCompleted handlers are same for both the button and the image. OnManipulationDelta() should look familiar, a similar implementation was used in the previous post, void OnManipulationDelta(object sender, ManipulationDeltaEventArgs args) {     FrameworkElement Elem = sender as FrameworkElement;       double Left = Canvas.GetLeft(Elem);     double Top = Canvas.GetTop(Elem);       Left += args.DeltaManipulation.Translation.X;     Top += args.DeltaManipulation.Translation.Y;       //check for bounds     if (Left < 0)     {         Left = 0;     }     else if (Left > (MainCanvas.ActualWidth - Elem.ActualWidth))     {         Left = MainCanvas.ActualWidth - Elem.ActualWidth;     }       if (Top < 0)     {         Top = 0;     }     else if (Top > (MainCanvas.ActualHeight - Elem.ActualHeight))     {         Top = MainCanvas.ActualHeight - Elem.ActualHeight;     }       Canvas.SetLeft(Elem, Left);     Canvas.SetTop(Elem, Top); } all it does is calculate the control’s position, check for bounds and then set the top and left of the control. OnManipulationCompleted() is more interesting because here we need to check if the gesture completed with any inertia and if it did, start the timer and continue to move the ui control until it comes to a halt slowly, void OnManipulationCompleted(object sender, ManipulationCompletedEventArgs args) {     FrameworkElement Elem = sender as FrameworkElement;       if (args.IsInertial)     {         ElemToMove = Elem;           Debug.WriteLine("Linear VelX:{0:0.00}  VelY:{1:0.00}", args.FinalVelocities.LinearVelocity.X,             args.FinalVelocities.LinearVelocity.Y);           ElemVelX = args.FinalVelocities.LinearVelocity.X / SPEED_FACTOR;         ElemVelY = args.FinalVelocities.LinearVelocity.Y / SPEED_FACTOR;           timer.Start();     } } ManipulationCompletedEventArgs contains a member, IsInertial, which is set to true if the manipulation was completed with some inertia. args.FinalVelocities.LinearVelocity.X and .Y will contain the velocities along the X and Y axis. We need to scale down these values so they can be used to increment the ui control’s position sensibly. A reference to the ui control is stored in ElemToMove and the velocities are stored as well, these will be used in the timer callback to access the ui control. And finally, we start the timer. The timer callback function is as follows, void OnTimerTick(object sender, EventArgs e) {     if (null != ElemToMove)     {         double Left, Top;         Left = Canvas.GetLeft(ElemToMove);         Top = Canvas.GetTop(ElemToMove);           Left += ElemVelX;         Top += ElemVelY;           //check for bounds         if (Left < 0)         {             Left = 0;             ElemVelX *= -1;         }         else if (Left > (MainCanvas.ActualWidth - ElemToMove.ActualWidth))         {             Left = MainCanvas.ActualWidth - ElemToMove.ActualWidth;             ElemVelX *= -1;         }           if (Top < 0)         {             Top = 0;             ElemVelY *= -1;         }         else if (Top > (MainCanvas.ActualHeight - ElemToMove.ActualHeight))         {             Top = MainCanvas.ActualHeight - ElemToMove.ActualHeight;             ElemVelY *= -1;         }           Canvas.SetLeft(ElemToMove, Left);         Canvas.SetTop(ElemToMove, Top);           //reduce x,y velocities gradually         ElemVelX *= 0.9;         ElemVelY *= 0.9;           //when velocities become too low, break         if (Math.Abs(ElemVelX) < 1.0 && Math.Abs(ElemVelY) < 1.0)         {             timer.Stop();             ElemToMove = null;         }     } } if ElemToMove is not null, we get the top and left values of the control and increment the values with their X and Y velocities. Check for bounds, and if the control goes out of bounds we reverse its velocity. Towards the end, the velocities are reduced by 10% every time the timer callback is called, and if the velocities reach too low values the timer is stopped and ElemToMove is made null. Here’s a short video of the program, the video is a little dodgy because my display driver refuses to run the animations smoothly. The flicks aren’t always recognised but the program should run well on an actual device (or a pc with better configuration), You can download the source code from here: ButtonDragAndFlick.zip

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• Someone tried to hack my Node.js server, need to understand a GET request in the logs

  - by Akay

  Alright, so I left my Node.js server alone for a while and came back to find some really interesting stuff in the logs. Apparently some moron from China or Poland tried to hack my server using directory traversal and what not, while it seems though he did not succeed I am unable understand few entries in the log. This is the output of a "hohup.out" file. The attack starts, apparently he is trying to find out some console entry in my server. All of which fail and return a 404. [90mGET /../../../../../../../../../../../ [31m500 [90m6ms - 2b[0m [90mGET /<script>alert(53416)</script> [33m404 [90m7ms[0m [90mGET / [32m200 [90m2ms - 240b[0m [90mGET / [32m200 [90m1ms - 240b[0m [90mGET / [32m200 [90m2ms - 240b[0m [90mGET /pz3yvy3lyzgja41w2sp [33m404 [90m1ms[0m [90mGET /stylesheets/style.css [33m404 [90m0ms[0m [90mGET /index.html [33m404 [90m1ms[0m [90mGET /index.htm [33m404 [90m0ms[0m [90mGET /default.html [33m404 [90m0ms[0m [90mGET /default.htm [33m404 [90m1ms[0m [90mGET /default.asp [33m404 [90m1ms[0m [90mGET /index.php [33m404 [90m0ms[0m [90mGET /default.php [33m404 [90m1ms[0m [90mGET /index.asp [33m404 [90m0ms[0m [90mGET /index.cgi [33m404 [90m0ms[0m [90mGET /index.jsp [33m404 [90m1ms[0m [90mGET /index.php3 [33m404 [90m0ms[0m [90mGET /index.pl [33m404 [90m0ms[0m [90mGET /default.jsp [33m404 [90m0ms[0m [90mGET /default.php3 [33m404 [90m0ms[0m [90mGET /index.html.en [33m404 [90m0ms[0m [90mGET /web.gif [33m404 [90m34ms[0m [90mGET /header.html [33m404 [90m1ms[0m [90mGET /homepage.nsf [33m404 [90m1ms[0m [90mGET /homepage.htm [33m404 [90m1ms[0m [90mGET /homepage.asp [33m404 [90m1ms[0m [90mGET /home.htm [33m404 [90m0ms[0m [90mGET /home.html [33m404 [90m1ms[0m [90mGET /home.asp [33m404 [90m1ms[0m [90mGET /login.asp [33m404 [90m0ms[0m [90mGET /login.html [33m404 [90m0ms[0m [90mGET /login.htm [33m404 [90m1ms[0m [90mGET /login.php [33m404 [90m0ms[0m [90mGET /index.cfm [33m404 [90m0ms[0m [90mGET /main.php [33m404 [90m1ms[0m [90mGET /main.asp [33m404 [90m1ms[0m [90mGET /main.htm [33m404 [90m1ms[0m [90mGET /main.html [33m404 [90m2ms[0m [90mGET /Welcome.html [33m404 [90m1ms[0m [90mGET /welcome.htm [33m404 [90m1ms[0m [90mGET /start.htm [33m404 [90m1ms[0m [90mGET /fleur.png [33m404 [90m0ms[0m [90mGET /level/99/ [33m404 [90m1ms[0m [90mGET /chl.css [33m404 [90m0ms[0m [90mGET /images/ [33m404 [90m0ms[0m [90mGET /robots.txt [33m404 [90m2ms[0m [90mGET /hb1/presign.asp [33m404 [90m1ms[0m [90mGET /NFuse/ASP/login.htm [33m404 [90m0ms[0m [90mGET /CCMAdmin/main.asp [33m404 [90m1ms[0m [90mGET /TiVoConnect?Command=QueryServer [33m404 [90m1ms[0m [90mGET /admin/images/rn_logo.gif [33m404 [90m1ms[0m [90mGET /vncviewer.jar [33m404 [90m1ms[0m [90mGET / [32m200 [90m2ms - 240b[0m [90mGET / [32m200 [90m2ms - 240b[0m [90mGET / [32m200 [90m7ms - 240b[0m [90mOPTIONS / [32m200 [90m1ms - 3b[0m [90mTRACE / [33m404 [90m0ms[0m [90mPROPFIND / [33m404 [90m0ms[0m [90mGET /\./ [33m404 [90m1ms[0m But here is when things start getting fishy. [90mGET http://www.google.com/ [32m200 [90m2ms - 240b[0m [90mGET http://www.google.com/ [32m200 [90m1ms - 240b[0m [90mGET http://www.google.com/ [32m200 [90m1ms - 240b[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET http://www.google.com/ [32m200 [90m1ms - 240b[0m [90mGET / [32m200 [90m2ms - 240b[0m [90mGET / [32m200 [90m1ms - 240b[0m [90mGET /robots.txt [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET http://www.google.com/ [32m200 [90m1ms - 240b[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m0ms[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m3ms[0m [90mGET /manager/html [33m404 [90m0ms[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m0ms[0m [90mGET http://www.google.com/ [32m200 [90m1ms - 240b[0m [90mGET http://37.28.156.211/sprawdza.php [33m404 [90m1ms[0m [90mGET http://www.google.com/ [32m200 [90m1ms - 240b[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET http://www.google.com/ [32m200 [90m2ms - 240b[0m [90mHEAD / [32m200 [90m1ms - 240b[0m [90mGET http://www.daydaydata.com/proxy.txt [33m404 [90m19ms[0m [90mHEAD / [32m200 [90m1ms - 240b[0m [90mGET /manager/html [33m404 [90m2ms[0m [90mGET / [32m200 [90m4ms - 240b[0m [90mGET http://www.google.pl/search?q=wp.pl [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m0ms[0m [90mHEAD / [32m200 [90m2ms - 240b[0m [90mGET http://www.google.pl/search?q=onet.pl [33m404 [90m1ms[0m [90mHEAD / [32m200 [90m2ms - 240b[0m [90mGET http://www.google.com/ [32m200 [90m1ms - 240b[0m [90mGET http://www.google.pl/search?q=ostro%C5%82%C4%99ka [33m404 [90m1ms[0m [90mGET http://www.google.pl/search?q=google [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET http://www.google.com/ [32m200 [90m2ms - 240b[0m [90mHEAD / [32m200 [90m2ms - 240b[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m0ms[0m [90mGET / [32m200 [90m2ms - 240b[0m [90mGET http://www.baidu.com/ [32m200 [90m2ms - 240b[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mPOST /api/login [32m200 [90m1ms - 28b[0m [90mGET /web-console/ServerInfo.jsp [33m404 [90m2ms[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET http://www.google.com/ [32m200 [90m10ms - 240b[0m [90mGET http://www.google.com/ [32m200 [90m1ms - 240b[0m [90mGET / [32m200 [90m2ms - 240b[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET http://proxyjudge.info [32m200 [90m2ms - 240b[0m [90mGET / [32m200 [90m2ms - 240b[0m [90mGET / [32m200 [90m1ms - 240b[0m [90mGET http://www.google.com/ [32m200 [90m3ms - 240b[0m [90mGET http://www.google.com/ [32m200 [90m3ms - 240b[0m [90mGET http://www.baidu.com/ [32m200 [90m1ms - 240b[0m [90mGET /manager/html [33m404 [90m0ms[0m [90mGET /manager/html [33m404 [90m1ms[0m [90mGET http://www.google.com/ [32m200 [90m2ms - 240b[0m [90mHEAD / [32m200 [90m1ms - 240b[0m [90mGET http://www.google.com/ [32m200 [90m1ms - 240b[0m [90mGET http://www.google.com/search?tbo=d&source=hp&num=1&btnG=Search&q=niceman [33m404 [90m2ms[0m So my questions are, how come my server is returning a "200" OK for root level domains? How did the hacker even manage to send a GET request to my server such that "http://www.google.com" shows up in the log while my server is simply an API that works on relative URLs such as "/api/login". And, while I looked up the OPTIONS, TRACE and PROPFIND HTTP requests that my server has logged it would be great if someone could explain what exactly was the hacker trying to achieve by using these verbs? Also what in the world does "[90m [32m [90m1ms - 240b[0m" mean? The "ms" makes sense, probably milliseconds for the request, rest I am unable to understand. Thank you!

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• Dojox grid having problem with Contentpane

  - by ice

  the grid appears properly on template's first loading. But when you click the paging button to load flooders.php thru list_result1() only the paging buttons will appear. I already tested the flooders.php outside the template and it works properly. what seems to be the problem? and what are the tools that i can use to see if the javascript is loading properly because i think the error console of ff browser which i use to track errors won't give you that much info when you are working with contentpane. thanks! ice note: below are the codes... ** from contentpane js function list_result1(){ args=""; uri = "flooders.php" + args; dojo.xhrGet( { url: uri, handleAs: "text", timeout: 500, // Time in milliseconds load: function(response, ioArgs) { //alert(response); dojo.byId("flooders_table").innerHTML = response; return response; }, // The ERROR function will be called in an error case. error: function(response, ioArgs) { console.error("HTTP status code: ", ioArgs.xhr.status); return response; } }); //end of dojo.xhrGet } **flooders.php starts here*** @import "js/dojo-0.9.0/dojo/resources/dojo.css"; @import "js/dojo-0.9.0/dijit/themes/tundra/tundra.css"; @import "js/dojo-0.9.0/dijit/themes/tundra/tundra_rtl.css"; @import "css/ash.css"; @import "js/dojo-0.9.0/dojox/grid/resources/Grid.css"; @import "js/dojo-0.9.0/dojox/grid/resources/tundraGrid.css"; @import "js/dojo-0.9.0/dojo/resources/dojo.css"; @import "js/dojo-0.9.0/dijit/tests/css/dijitTests.css"; .dojoxGridRowEditing td { background-color: #F4FFF4; } .dojoxGrid input, .dojoxGrid select, .dojoxGrid textarea { margin: 0; padding: 0; border-style: none; width: 100%; font-size: 100%; font-family: inherit; } .dojoxGrid input { } .dojoxGrid select { } .dojoxGrid textarea { } #controls { padding: 0px 0; } #controls button { margin-left: 10px; } .myGrid { width: 550px; height: 230px; margin-left: 20px; /* border: 1px solid silver; */ } echo " // it has script heading here (function(){ // some sample data // global var 'data' data = { identifier: 'id', label: 'id', items: [] }; data_list = [ $banlist ]; var rows = $listnum ; var x=1; for(var i=0, l=data_list.length; i // global var 'test_store' test_store = new dojo.data.ItemFileWriteStore({data: data}); })(); // it has ending here "; ?   -- here's the javascript dojo.require("dijit.TitlePane"); dojo.require("dijit.dijit"); dojo.require("dojox.grid.DataGrid"); dojo.require("dojo.data.ItemFileWriteStore"); dojo.require("dojo.parser"); // scan page for widgets and instantiate them dojo.require("dijit.layout.LayoutContainer"); dojo.require("dijit.layout.AccordionContainer"); dojo.require("dijit.layout.ContentPane"); dojo.require("dijit.layout.TabContainer"); dojo.require("dijit.Editor"); dojo.require("dijit._editor.plugins.AlwaysShowToolbar"); dojo.require("dijit._editor.plugins.LinkDialog"); //this must be inlcuded below function() selectCell = { styles: 'text-align: center;', type: dojox.grid.cells.Select }; gridLayout = { defaultCell: { width: 5, styles: 'text-align: right;' }, rows: [ [ { name: 'Mark', width: 3, field: 'col1', editable: true, styles: 'text-align: center;', type: dojox.grid.cells.Bool }, { name: 'Id', width: 3, field: 'id' , editable: false }, { name: 'Username', field: 'col2', editable: false, styles: '', width: '70%' }, { name: 'Reason', field: 'col3', editable: false , styles: '', width: '100%' }, { name: 'Date Banned', field: 'col4', editable: false , styles: '', width: '70%' } ] ] };

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• Game loop and time tracking

  - by David Brown

  Maybe I'm just an idiot, but I've been trying to implement a game loop all day and it's just not clicking. I've read literally every article I could find on Google, but the problem is that they all use different timing mechanisms, which makes them difficult to apply to my particular situation (some use milliseconds, other use ticks, etc). Basically, I have a Clock object that updates each time the game loop executes. internal class Clock { public static long Timestamp { get { return Stopwatch.GetTimestamp(); } } public static long Frequency { get { return Stopwatch.Frequency; } } private long _startTime; private long _lastTime; private TimeSpan _totalTime; private TimeSpan _elapsedTime; /// <summary> /// The amount of time that has passed since the first step. /// </summary> public TimeSpan TotalTime { get { return _totalTime; } } /// <summary> /// The amount of time that has passed since the last step. /// </summary> public TimeSpan ElapsedTime { get { return _elapsedTime; } } public Clock() { Reset(); } public void Reset() { _startTime = Timestamp; _lastTime = 0; _totalTime = TimeSpan.Zero; _elapsedTime = TimeSpan.Zero; } public void Tick() { long currentTime = Timestamp; if (_lastTime == 0) _lastTime = currentTime; _totalTime = TimestampToTimeSpan(currentTime - _startTime); _elapsedTime = TimestampToTimeSpan(currentTime - _lastTime); _lastTime = currentTime; } public static TimeSpan TimestampToTimeSpan(long timestamp) { return TimeSpan.FromTicks( (timestamp * TimeSpan.TicksPerSecond) / Frequency); } } I based most of that on the XNA GameClock, but it's greatly simplified. Then, I have a Time class which holds various times that the Update and Draw methods need to know. public class Time { public TimeSpan ElapsedVirtualTime { get; internal set; } public TimeSpan ElapsedRealTime { get; internal set; } public TimeSpan TotalVirtualTime { get; internal set; } public TimeSpan TotalRealTime { get; internal set; } internal Time() { } internal Time(TimeSpan elapsedVirtualTime, TimeSpan elapsedRealTime, TimeSpan totalVirutalTime, TimeSpan totalRealTime) { ElapsedVirtualTime = elapsedVirtualTime; ElapsedRealTime = elapsedRealTime; TotalVirtualTime = totalVirutalTime; TotalRealTime = totalRealTime; } } My main class keeps a single instance of Time, which it should constantly update during the game loop. So far, I have this: private static void Loop() { do { Clock.Tick(); Time.TotalRealTime = Clock.TotalTime; Time.ElapsedRealTime = Clock.ElapsedTime; InternalUpdate(Time); InternalDraw(Time); } while (!_exitRequested); } The real time properties of the time class turn out great. Now I'd like to get a proper update/draw loop working so that the state is updated a variable number of times per frame, but at a fixed timestep. At the same time, the Time.TotalVirtualTime and Time.ElapsedVirtualTime should be updated accordingly. In addition, I intend for this to support multiplayer in the future, in case that makes any difference to the design of the game loop. Any tips or examples on how I could go about implementing this (aside from links to articles)?

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• Example map-reduce oozie program not working on CDH 4.5

  - by user2002748

  I am using Hadoop (CDH 4.5) on my mac since some time now, and do run map reduce jobs regularly. I installed oozie recently (again, CDH4.5) following instructions at: http://archive.cloudera.com/cdh4/cdh/4/oozie-3.3.2-cdh4.5.0/DG_QuickStart.html, and tried to run sample programs provided. However, it always fails with the following error. Looks like the workflow is not getting run at all. The Console URL field in the Job info is also empty. Could someone please help on this? The relevant snippet of the Oozie Job log follows. 2014-06-10 17:27:18,414 INFO ActionStartXCommand:539 - USER[userXXX] GROUP[-] TOKEN[] APP[map-reduce-wf] JOB[0000000-140610172702069-oozie-usrX-W] ACTION[0000000-140610172702069-oozie-usrX-W@:start:] Start action [0000000-140610172702069-oozie-usrX-W@:start:] with user-retry state : userRetryCount [0], userRetryMax [0], userRetryInterval [10] 2014-06-10 17:27:18,417 WARN ActionStartXCommand:542 - USER[userXXX] GROUP[-] TOKEN[] APP[map-reduce-wf] JOB[0000000-140610172702069-oozie-usrX-W] ACTION[0000000-140610172702069-oozie-usrX-W@:start:] [***0000000-140610172702069-oozie-usrX-W@:start:***]Action status=DONE 2014-06-10 17:27:18,417 WARN ActionStartXCommand:542 - USER[userXXX] GROUP[-] TOKEN[] APP[map-reduce-wf] JOB[0000000-140610172702069-oozie-usrX-W] ACTION[0000000-140610172702069-oozie-usrX-W@:start:] [***0000000-140610172702069-oozie-usrX-W@:start:***]Action updated in DB! 2014-06-10 17:27:18,576 INFO ActionStartXCommand:539 - USER[userXXX] GROUP[-] TOKEN[] APP[map-reduce-wf] JOB[0000000-140610172702069-oozie-usrX-W] ACTION[0000000-140610172702069-oozie-usrX-W@mr-node] Start action [0000000-140610172702069-oozie-usrX-W@mr-node] with user-retry state : userRetryCount [0], userRetryMax [0], userRetryInterval [10] 2014-06-10 17:27:19,188 WARN MapReduceActionExecutor:542 - USER[userXXX] GROUP[-] TOKEN[] APP[map-reduce-wf] JOB[0000000-140610172702069-oozie-usrX-W] ACTION[0000000-140610172702069-oozie-usrX-W@mr-node] credentials is null for the action 2014-06-10 17:27:19,423 WARN ActionStartXCommand:542 - USER[userXXX] GROUP[-] TOKEN[] APP[map-reduce-wf] JOB[0000000-140610172702069-oozie-usrX-W] ACTION[0000000-140610172702069-oozie-usrX-W@mr-node] Error starting action [mr-node]. ErrorType [TRANSIENT], ErrorCode [JA009], Message [JA009: Unknown rpc kind RPC_WRITABLE] org.apache.oozie.action.ActionExecutorException: JA009: Unknown rpc kind RPC_WRITABLE at org.apache.oozie.action.ActionExecutor.convertExceptionHelper(ActionExecutor.java:418) at org.apache.oozie.action.ActionExecutor.convertException(ActionExecutor.java:392) at org.apache.oozie.action.hadoop.JavaActionExecutor.submitLauncher(JavaActionExecutor.java:773) at org.apache.oozie.action.hadoop.JavaActionExecutor.start(JavaActionExecutor.java:927) at org.apache.oozie.command.wf.ActionStartXCommand.execute(ActionStartXCommand.java:211) at org.apache.oozie.command.wf.ActionStartXCommand.execute(ActionStartXCommand.java:59) at org.apache.oozie.command.XCommand.call(XCommand.java:277) at org.apache.oozie.service.CallableQueueService$CompositeCallable.call(CallableQueueService.java:326) at org.apache.oozie.service.CallableQueueService$CompositeCallable.call(CallableQueueService.java:255) at org.apache.oozie.service.CallableQueueService$CallableWrapper.run(CallableQueueService.java:175) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:744) Caused by: org.apache.hadoop.ipc.RemoteException(java.io.IOException): Unknown rpc kind RPC_WRITABLE at org.apache.hadoop.ipc.Client.call(Client.java:1238) at org.apache.hadoop.ipc.WritableRpcEngine$Invoker.invoke(WritableRpcEngine.java:225) at org.apache.hadoop.mapred.$Proxy30.getDelegationToken(Unknown Source) at org.apache.hadoop.mapred.JobClient.getDelegationToken(JobClient.java:2125) at org.apache.oozie.service.HadoopAccessorService.createJobClient(HadoopAccessorService.java:372) at org.apache.oozie.action.hadoop.JavaActionExecutor.createJobClient(JavaActionExecutor.java:970) at org.apache.oozie.action.hadoop.JavaActionExecutor.submitLauncher(JavaActionExecutor.java:723) ... 10 more 2014-06-10 17:27:19,426 INFO ActionStartXCommand:539 - USER[userXXX] GROUP[-] TOKEN[] APP[map-reduce-wf] JOB[0000000-140610172702069-oozie-usrX-W] ACTION[0000000-140610172702069-oozie-usrX-W@mr-node] Next Retry, Attempt Number [1] in [60,000] milliseconds 2014-06-10 17:28:19,468 INFO ActionStartXCommand:539 - USER[userXXX] GROUP[-] TOKEN[] APP[map-reduce-wf] JOB[0000000-140610172702069-oozie-usrX-W] ACTION[0000000-140610172702069-oozie-usrX-W@mr-node] Start action [0000000-140610172702069-oozie-usrX-W@mr-node] with user-retry state : userRetryCount [0], userRetryMax [0], userRetryInterval [10]

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• Using DateTime in a SqlParameter for Stored Procedure, format error

  - by Matt

  I'm trying to call a stored procedure (on a SQL 2005 server) from C#, .NET 2.0 using DateTime as a value to a SqlParameter. The SQL type in the stored procedure is 'datetime'. Executing the sproc from SQL Management Studio works fine. But everytime I call it from C# I get an error about the date format. When I run SQL Profiler to watch the calls, I then copy paste the exec call to see whats going on. These are my observations and notes about what I've attempted: 1) If I pass the DateTime in directly as a DateTime or converted to SqlDateTime, the field is surrounding by a PAIR of single quotes, such as @Date_Of_Birth=N''1/8/2009 8:06:17 PM'' 2) If I pass the DateTime in as a string, I only get the single quotes 3) Using SqlDateTime.ToSqlString() does not result in a UTC formatted datetime string (even after converting to universal time) 4) Using DateTime.ToString() does not result in a UTC formatted datetime string. 5) Manually setting the DbType for the SqlParameter to DateTime does not change the above observations. So, my questions then, is how on earth do I get C# to pass the properly formatted time in the SqlParameter? Surely this is a common use case, why is it so difficult to get working? I can't seem to convert DateTime to a string that is SQL compatable (e.g. '2009-01-08T08:22:45') EDIT RE: BFree, the code to actually execute the sproc is as follows: using (SqlCommand sprocCommand = new SqlCommand(sprocName)) { sprocCommand.Connection = transaction.Connection; sprocCommand.Transaction = transaction; sprocCommand.CommandType = System.Data.CommandType.StoredProcedure; sprocCommand.Parameters.AddRange(parameters.ToArray()); sprocCommand.ExecuteNonQuery(); } To go into more detail about what I have tried: parameters.Add(new SqlParameter("@Date_Of_Birth", DOB)); parameters.Add(new SqlParameter("@Date_Of_Birth", DOB.ToUniversalTime())); parameters.Add(new SqlParameter("@Date_Of_Birth", DOB.ToUniversalTime().ToString())); SqlParameter param = new SqlParameter("@Date_Of_Birth", System.Data.SqlDbType.DateTime); param.Value = DOB.ToUniversalTime(); parameters.Add(param); SqlParameter param = new SqlParameter("@Date_Of_Birth", SqlDbType.DateTime); param.Value = new SqlDateTime(DOB.ToUniversalTime()); parameters.Add(param); parameters.Add(new SqlParameter("@Date_Of_Birth", new SqlDateTime(DOB.ToUniversalTime()).ToSqlString())); Additional EDIT The one I thought most likely to work: SqlParameter param = new SqlParameter("@Date_Of_Birth", System.Data.SqlDbType.DateTime); param.Value = DOB; Results in this value in the exec call as seen in the SQL Profiler @Date_Of_Birth=''2009-01-08 15:08:21:813'' If I modify this to be @Date_Of_Birth='2009-01-08T15:08:21' It works, but it won't parse with pair of single quotes, and it wont convert to a datetime correctly with the space between the date and time and with the milliseconds on the end. Update and Success First and foremost, thank you everyone for the answers. I post this for the sake of completeness and accuracy on SO - because I certainly do not do it for my pride... I had copy/pasted the code above after the request from below. I trimmed things here and there to be concise. Turns out my problem was in the code I left out, which I'm sure any one of you would have spotted in an instant. I had wrapped my sproc calls inside a transaction. Turns out that I was simply not doing transaction.Commit()!!!!! I'm ashamed to say it, but there you have it. I still don't know what's going on with the syntax I get back from the profiler. A coworker watched with his own instance of the profiler from his computer, and it returned proper syntax. Watching the very SAME executions from my profiler showed the incorrect syntax. It acted as a red-herring, making me believe there was a query syntax problem instead of the much more simple and true answer, which was that I need to commit the transaction! I marked an answer below as correct, and threw in some up-votes on others because they did, after all, answer the question, even if they didn't fix my specific (brain lapse) issue. Thanks again for the help.

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• Why do I get the error "Only antlib URIs can be located from the URI alone,not the URI" when trying to run hibernate tools in my build.xml

  - by Casbah

  I'm trying to run hibernate tools in an ant build to generate ddl from my JPA annotations. Ant dies on the taskdef tag. I've tried with ant 1.7, 1.6.5, and 1.6 to no avail. I've tried both in eclipse and outside. I've tried including all the hbn jars in the hibernate-tools path and not. Note that I based my build file on this post: http://stackoverflow.com/questions/281890/hibernate-jpa-to-ddl-command-line-tools I'm running eclipse 3.4 with WTP 3.0.1 and MyEclipse 7.1 on Ubuntu 8. Build.xml: <project name="generateddl" default="generate-ddl"> <path id="hibernate-tools"> <pathelement location="../libraries/hibernate-tools/hibernate-tools.jar" /> <pathelement location="../libraries/hibernate-tools/bsh-2.0b1.jar" /> <pathelement location="../libraries/hibernate-tools/freemarker.jar" /> <pathelement location="../libraries/jtds/jtds-1.2.2.jar" /> <pathelement location="../libraries/hibernate-tools/jtidy-r8-20060801.jar" /> </path> <taskdef classname="org.hibernate.tool.ant.HibernateToolTask" classpathref="hibernate-tools"/> <target name="generate-ddl" description="Export schema to DDL file"> <!-- compile model classes before running hibernatetool --> <!-- task definition; project.class.path contains all necessary libs <taskdef name="hibernatetool" classname="org.hibernate.tool.ant.HibernateToolTask" classpathref="project.class.path" /> --> <hibernatetool destdir="sql"> <!-- check that directory exists --> <jpaconfiguration persistenceunit="default" /> <classpath> <dirset dir="WebRoot/WEB-INF/classes"> <include name="**/*"/> </dirset> </classpath> <hbm2ddl outputfilename="schemaexport.sql" format="true" export="false" drop="true" /> </hibernatetool> </target> Error message (ant -v): Apache Ant version 1.7.0 compiled on December 13 2006 Buildfile: /home/joe/workspace/bento/ant-generate-ddl.xml parsing buildfile /home/joe/workspace/bento/ant-generate-ddl.xml with URI = file:/home/joe/workspace/bento/ant-generate-ddl.xml Project base dir set to: /home/joe/workspace/bento [antlib:org.apache.tools.ant] Could not load definitions from resource org/apache/tools/ant/antlib.xml. It could not be found. BUILD FAILED /home/joe/workspace/bento/ant-generate-ddl.xml:12: Only antlib URIs can be located from the URI alone,not the URI at org.apache.tools.ant.taskdefs.Definer.execute(Definer.java:216) at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:105) at org.apache.tools.ant.Task.perform(Task.java:348) at org.apache.tools.ant.Target.execute(Target.java:357) at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:140) at org.eclipse.ant.internal.ui.antsupport.InternalAntRunner.parseBuildFile(InternalAntRunner.java:191) at org.eclipse.ant.internal.ui.antsupport.InternalAntRunner.run(InternalAntRunner.java:400) at org.eclipse.ant.internal.ui.antsupport.InternalAntRunner.main(InternalAntRunner.java:137) Total time: 195 milliseconds

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• How to get IMediaControl.Run() to start a file playing with no delay

  - by MusiGenesis

  I am attempting to use DirectShow to play two AVI files consecutively (one after the other) so that there is no interruption in the audio or video when the player transitions from one file to the next. I have two custom controls on my form. Each one is pre-loaded with an AVI file, and before playback begins I set up all the DirectShow interfaces, set the video windows and resize them, call IMediaControl.Run(), then IMediaControl.Pause(), then IMediaSeeking.SetPositions to reset to frame 0, on both controls. On the form, you can see that both files are paused at their initial frames. I then call IMediaControl.Run() on the first control, and wait for it to complete before calling Run() on the second control. Initially, I hooked into the first video's EC_COMPLETE notification message, and used this to start the second. Thinking that this event might be slow to arrive (turns out it is, but for a weird reason), I tried two other approaches: Check the first video's current position inside a timer that goes off every second or so (using IMediaPosition.get_CurrentPosition). When the current position is within a second of the video's stop time (known in advance from IMediaPosition.get_StopTime), I go into a tight while loop and wait for the current position to equal the stop time, and then call Run() on the second video. Same as the first, except I replace the while loop with a call to timeSetEvent from winmm.dll, with a delay set so that it fires right when the first file is supposed to end. I use the callback to Run() the second file. Either of these two methods substantially cuts down the delay between the end of the first file and the beginning of the second, indicating that the EC_COMPLETE message doesn't arrive immediately after the file is complete (I also tried hooking the EC_SEGMENT_COMPLETE message, which is supposed to be used for looping within a file, but apparently nobody supports this - it never occurs on my machine, at least). Doing all of the above has cut the transition delay from as much as a second, down to a barely perceptible glitch; about a third of the time the files transition with no interruption at all, which suggests there's no fundamental reason I can't get this to work all the time. The slight delay is still unacceptable, unfortunately. I assume (and I could easily be wrong) that the remaining delay is due to a slight variable delay between the call to IMediaControl.Run() and when the video actually starts playing. Does anybody know anything I can do to eliminate this little lag? It would also help to be told this is fundamentally impossible for whatever reason, which wouldn't surprise me. I've never encountered a video player in Windows that doesn't have this problem, so it may not be doable. More info: the AVI files I'm playing are completely uncompressed (video and audio are uncompressed), so I don't think the lag is due to DirectShow's having to uncompress the video ahead of play start, although it may still buffer ahead as matter of course (and this may be the source of the problem). I would have though that starting play, pausing and then rewinding to the beginning would fix this. Also, the way I'm handling the transition is to actually have the second control underneath the first; when the first completes playing, I start the second and then call BringToFront on it, creating the appearance of a single video transitioning between the two originals. I don't think the glitch is due to this, because it works perfectly some of the time, and even if this were problematic, it wouldn't explain the matching audio glitch. Even more: I just tried starting the second video 30-50 milliseconds "early" and that seemed to eliminate even more of the gap, so I'm guessing that the lag in Run() is about that long. It appears to be variable, though, so this is still not where I need it to be.

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• Quartz Thread Execution Parallel or Sequential?

  - by vikas

  We have a quartz based scheduler application which runs about 1000 jobs per minute which are evenly distributed across seconds of each minute i.e. about 16-17 jobs per second. Ideally, these 16-17 jobs should fire at same time, however our first statement, which simply logs the time of execution, of execute method of the job is being called very late. e.g. let us assume we have 1000 jobs scheduled per minute from 05:00 to 05:04. So, ideally the job which is scheduled at 05:03:50 should have logged the first statement of the execute method at 05:03:50, however, it is doing it at about 05:06:38. I have tracked down the time taken by the scheduled job which comes around 15-20 milliseconds. This scheduled job is fast enough because we just send a message on an ActiveMQ queue. We have specified the number of threads of quartz to be 100 and even tried with increasing it to 200 and more, but no gain. One more thing we noticed is that logs from scheduler are coming sequential after first 1 minute i.e. [Quartz_Worker_28] <Some log statement> .. .. [Quartz_Worker_29] <Some log statement> .. .. [Quartz_Worker_30] <Some log statement> .. .. So it suggesting that after some time quartz is running threads almost sequential. May be this is happening due to the time taken in notifying the job completion to persistence store (which is a separate postgres database in this case) and/or context switching. What can be the reason behind this strange behavior? EDIT: More detailed Log [06/07/12 10:08:37:192][QuartzScheduler_Worker-34][INFO] org.quartz.plugins.history.LoggingTriggerHistoryPlugin - Trigger [<trigger_name>] fired job [<job_name>] scheduled at: 06-07-2012 10:08:33.458, next scheduled at: 06-07-2012 10:34:53.000 [06/07/12 10:08:37:192][QuartzScheduler_Worker-34][INFO] <my_package>.scheduler.quartz.ScheduledLocateJob - execute begin--------- ScheduledLocateJob with key: <job_name> started at Fri Jul 06 10:08:37 EDT 2012 [06/07/12 10:08:37:192][QuartzScheduler_Worker-34][INFO] <my_package>.scheduler.quartz.ScheduledLocateJob <some log statement> [06/07/12 10:08:37:192][QuartzScheduler_Worker-34][INFO] <my_package>.scheduler.quartz.ScheduledLocateJob <some log statement> [06/07/12 10:08:37:192][QuartzScheduler_Worker-34][INFO] <my_package>.scheduler.quartz.ScheduledLocateJob <some log statement> [06/07/12 10:08:37:220][QuartzScheduler_Worker-34][INFO] <my_package>.scheduler.quartz.ScheduledLocateJob - execute end--------- ScheduledLocateJob with key: <job_name> ended at Fri Jul 06 10:08:37 EDT 2012 [06/07/12 10:08:37:220][QuartzScheduler_Worker-34][INFO] org.quartz.plugins.history.LoggingTriggerHistoryPlugin - Trigger [<trigger_name>] completed firing job [<job_name>] with resulting trigger instruction code: DO NOTHING. Next scheduled at: 06-07-2012 10:34:53.000 I am doubting on this section of the above log scheduled at: 06-07-2012 10:08:33.458, next scheduled at: 06-07-2012 10:34:53.000 because this job was scheduled for 10:04:53, but it fired at 10:08:33 and still quartz didn't consider it as misfire. Shouldn't it be a misfire?

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• Java Synchronized List Deadlock

  - by portoalet

  From Effective Java 2nd edition item 67 page 266-268: The background thread calls s.removeObserver, which attempts to lock observers, but it can’t acquire the lock, because the main thread already has the lock. All the while, the main thread is waiting for the background thread to finish removing the observer, which explains the deadlock. I am trying to find out which threads deadlock in the main method by using ThreadMXBean (http://stackoverflow.com/questions/1102359/programmatic-deadlock-detection-in-java) , but why does it not return the deadlocked threads? I used a new Thread to run the ThreadMXBean detection. public class ObservableSet<E> extends ForwardingSet<E> { public ObservableSet(Set<E> set) { super(set); } private final List<SetObserver<E>> observers = new ArrayList<SetObserver<E>>(); public void addObserver(SetObserver<E> observer) { synchronized(observers) { observers.add(observer); } } public boolean removeObserver(SetObserver<E> observer) { synchronized(observers) { return observers.remove(observer); } } private void notifyElementAdded(E element) { synchronized(observers) { for (SetObserver<E> observer : observers) observer.added(this, element); } } @Override public boolean add(E element) { boolean added = super.add(element); if (added) notifyElementAdded(element); return added; } @Override public boolean addAll(Collection<? extends E> c) { boolean result = false; for (E element : c) result|=add(element); //callsnotifyElementAdded return result; } public static void main(String[] args) { ObservableSet<Integer> set = new ObservableSet<Integer>(new HashSet<Integer>()); final ThreadMXBean threadMxBean = ManagementFactory.getThreadMXBean(); Thread t = new Thread(new Runnable() { @Override public void run() { while( true ) { long [] threadIds = threadMxBean.findDeadlockedThreads(); if( threadIds != null) { ThreadInfo[] infos = threadMxBean.getThreadInfo(threadIds); for( ThreadInfo threadInfo : infos) { StackTraceElement[] stacks = threadInfo.getStackTrace(); for( StackTraceElement stack : stacks ) { System.out.println(stack.toString()); } } } try { System.out.println("Sleeping.."); TimeUnit.MILLISECONDS.sleep(1000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }); t.start(); set.addObserver(new SetObserver<Integer>() { public void added(ObservableSet<Integer> s, Integer e) { ExecutorService executor = Executors.newSingleThreadExecutor(); final SetObserver<Integer> observer = this; try { executor.submit(new Runnable() { public void run() { s.removeObserver(observer); } }).get(); } catch (ExecutionException ex) { throw new AssertionError(ex.getCause()); } catch (InterruptedException ex) { throw new AssertionError(ex.getCause()); } finally { executor.shutdown(); } } }); for (int i = 0; i < 100; i++) set.add(i); } } public interface SetObserver<E> { // Invoked when an element is added to the observable set void added(ObservableSet<E> set, E element); } // ForwardingSet<E> simply wraps another Set and forwards all operations to it.

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• Can't remove Enter_Frame and stop TimerEvent

  - by Hwang

  I wanted to remove an ENTER_FRAME object and stopping an TimerEvent when I click on a button, and rerun ENTER_FRAME and TimerEvent when I click on another button. I've tried removeAddEventListener and stop() for the time, but I won't work. Any idea whats the problem here? package{ import flash.display.MovieClip; import flash.display.DisplayObject; import flash.events.Event; import flash.events.TimerEvent; import flash.utils.Timer; public class clockFunction extends MovieClip { private var clock:clockMC=new clockMC(); private var countdownTimer:Timer; //seconds private var secTop1=clock.second.top1.digit; private var secTop2=clock.second.top2.digit; private var secBot1=clock.second.bot1.digit; private var secBot2=clock.second.bot2.digit; private var seconds:Number; private var minutes:Number; private var hours:Number; private var days:Number; public function clockFunction():void { decrease(); addChild(clock); } private function decrease():void { countdownTimer=new Timer(1000); //Adding an event listener to the timer object countdownTimer.addEventListener(TimerEvent.TIMER,updateTime); //Initializing timer object //countdownTimer.start(); } private function updateTime(event:TimerEvent):void { decreasTimerFunction(); clock.second.play(); if (seconds==1) { clock.minute.play(); } if ((minutes==1)&&(seconds==1)) { clock.hour.play(); } if ((hours==1)&&(minutes==1)&&(seconds==1)) { clock.day.play(); } } //Setting it back to its correct time so it won't have number changing in between of flipping issues. private function detect(event:Event):void { //seconds var sec1=seconds; var sec2=seconds-1; if (sec1<10) { sec1="0"+sec1; } if (sec2<10) { sec2="0"+sec2; } if (sec1==00) { sec2=59; } secTop1.text=sec1; secTop2.text=sec2; secBot1.text=sec1; secBot2.text=sec2; } public function startTime():void { addEventListener(Event.ENTER_FRAME,detect); countdownTimer.start(); trace("start"); } public function stopTime():void { countdownTimer.stop(); removeEventListener(Event.ENTER_FRAME,detect); trace("stop"); } private function decreasTimerFunction():void { //Create a date object for Christmas Morning var endTime:Date=new Date(2010,3,26,20,0,0); //Current date object var now:Date=new Date(); // Set the difference between the two date and times in milliseconds var timeDiff:Number=endTime.getTime()-now.getTime(); seconds=Math.floor(timeDiff/1000); minutes=Math.floor(seconds/60); hours=Math.floor(minutes/60); days=Math.floor(hours/24); // Set the remainder of the division vars above hours%=24; minutes%=60; seconds%=60; } } }

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• jQuery image crossfader problem

  - by Dr Casper Black

  Hey!, I have a image switcher fadein/out (it will crossfade iamges - auto(1 - x) ) and a pager but i cant manage to make the image rotation listen the click action on pager, when clicked on pager the image will NOT jup tu the specific img. The problem is in the rotate function the triggerID will hold the "rel" num of the current pager-element which is the equivalent to the image "list" num, so when clicked on the pager, the triggerID will show the rel number that was clicked... can i use that to display the image Here is the code for JQ: $(".paging a:first").addClass("active"); //Rotation rotate = function(){ var triggerID = $active.attr("rel"); //Get number of times to images $(".paging a").removeClass('active'); //Remove all active class $active.addClass('active'); //Add active class (the $active is declared in the rotateSwitch function) //CrossFade Animation var $activeImg = $('.image_reel img.active'); if ( $activeImg.length == 0 ) $activeImg = $('.image_reel img:last'); var $next = $activeImg.next().length ? $activeImg.next() : $('.image_reel img:first'); $activeImg.addClass('last-active'); $next.css({opacity: 0.0}) .addClass('active') .animate({opacity: 1.0}, 500, function() { $activeImg.removeClass('active last-active'); }); }; //Rotation and Timing Event rotateSwitch = function(){ play = setInterval(function(){ //Set timer - this will repeat itself every 3 seconds $active = $('.paging a.active').next(); //Move to the next paging if ( $active.length === 0) { //If paging reaches the end... $active = $('.paging a:first'); //go back to first } rotate(); //Trigger the paging and slider function }, 3000); //Timer speed in milliseconds (3 seconds) }; rotateSwitch(); //Run function on launch //On Click $(".paging a").click(function() { $active = $(this); //Activate the clicked paging //Reset Timer clearInterval(play); //Stop the rotation rotate(); //Trigger rotation immediately rotateSwitch(); // Resume rotation timer return false; //Prevent browser jump to link anchor }); The HTML code: <div class="image_reel"> <img src="images/slideshow/img1.jpg" alt="image 1" class="active"> <img src="images/slideshow/img2.jpg" alt="image 2"> <img src="images/slideshow/img3.jpg" alt="image 3"> <img src="images/slideshow/img4.jpg" alt="image 4"> </div> <div class="paging"> <a href="#" rel="1" title="image 1">&nbsp;</a> <a href="#" rel="2" title="image 2">&nbsp;</a> <a href="#" rel="3" title="image 3">&nbsp;</a> <a href="#" rel="4" title="image 4">&nbsp;</a> </div> plz help.

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• Public class DiscoLight help

  - by luvthug

  Hi All, If some one can point me in the right direction for this code for my assigment I would really appreciate it. I have pasted the whole code that I need to complete but I need help with the following method public void changeColour(Circle aCircle) which is meant to allow to change the colour of the circle randomly, if 0 comes the light of the circle sgould change to red, 1 for green and 2 for purple. public class DiscoLight { /* instance variables */ private Circle light; // simulates a circular disco light in the Shapes window private Random randomNumberGenerator; /** * Default constructor for objects of class DiscoLight */ public DiscoLight() { super(); this.randomNumberGenerator = new Random(); } /** * Returns a randomly generated int between 0 (inclusive) * and number (exclusive). For example if number is 6, * the method will return one of 0, 1, 2, 3, 4, or 5. */ public int getRandomInt(int number) { return this.randomNumberGenerator.nextInt(number); } /** * student to write code and comment here for setLight(Circle) for Q4(i) */ public void setLight(Circle aCircle) { this.light = aCircle; } /** * student to write code and comment here for getLight() for Q4(i) */ public Circle getLight() { return this.light; } /** * Sets the argument to have a diameter of 50, an xPos * of 122, a yPos of 162 and the colour GREEN. * The method then sets the receiver's instance variable * light, to the argument aCircle. */ public void addLight(Circle aCircle) { //Student to write code here, Q4(ii) this.light = aCircle; this.light.setDiameter(50); this.light.setXPos(122); this.light.setYPos(162); this.light.setColour(OUColour.GREEN); } /** * Randomly sets the colour of the instance variable * light to red, green, or purple. */ public void changeColour(Circle aCircle) { //student to write code here, Q4(iii) if (getRandomInt() == 0) { this.light.setColour(OUColour.RED); } if (this.getRandomInt().equals(1)) { this.light.setColour(OUColour.GREEN); } else if (this.getRandomInt().equals(2)) { this.light.setColour(OUColour.PURPLE); } } /** * Grows the diameter of the circle referenced by the * receiver's instance variable light, to the argument size. * The diameter is incremented in steps of 2, * the xPos and yPos are decremented in steps of 1 until the * diameter reaches the value given by size. * Between each step there is a random colour change. The message * delay(anInt) is used to slow down the graphical interface, as required. */ public void grow(int size) { //student to write code here, Q4(iv) } /** * Shrinks the diameter of the circle referenced by the * receiver's instance variable light, to the argument size. * The diameter is decremented in steps of 2, * the xPos and yPos are incremented in steps of 1 until the * diameter reaches the value given by size. * Between each step there is a random colour change. The message * delay(anInt) is used to slow down the graphical interface, as required. */ public void shrink(int size) { //student to write code here, Q4(v) } /** * Expands the diameter of the light by the amount given by * sizeIncrease (changing colour as it grows). * * The method then contracts the light until it reaches its * original size (changing colour as it shrinks). */ public void lightCycle(int sizeIncrease) { //student to write code here, Q4(vi) } /** * Prompts the user for number of growing and shrinking * cycles. Then prompts the user for the number of units * by which to increase the diameter of light. * Method then performs the requested growing and * shrinking cycles. */ public void runLight() { //student to write code here, Q4(vii) } /** * Causes execution to pause by time number of milliseconds */ private void delay(int time) { try { Thread.sleep(time); } catch (Exception e) { System.out.println(e); } } }

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• C++ MySQL++ Delete query statement brain killer question

  - by shauny

  Hello all, I'm relatively new to the MySQL++ connector in C++, and have an really annoying issue with it already! I've managed to get stored procedures working, however i'm having issues with the delete statements. I've looked high and low and have found no documentation with examples. First I thought maybe the code needs to free the query/connection results after calling the stored procedure, but of course MySQL++ doesn't have a free_result method... or does it? Anyways, here's what I've got: #include <iostream> #include <stdio.h> #include <queue> #include <deque> #include <sys/stat.h> #include <mysql++/mysql++.h> #include <boost/thread/thread.hpp> #include "RepositoryQueue.h" using namespace boost; using namespace mysqlpp; class RepositoryChecker { private: bool _isRunning; Connection _con; public: RepositoryChecker() { try { this->_con = Connection(false); this->_con.set_option(new MultiStatementsOption(true)); this->_con.set_option(new ReconnectOption(true)); this->_con.connect("**", "***", "***", "***"); this->ChangeRunningState(true); } catch(const Exception& e) { this->ChangeRunningState(false); } } /** * Thread method which runs and creates the repositories */ void CheckRepositoryQueues() { //while(this->IsRunning()) //{ std::queue<RepositoryQueue> queues = this->GetQueue(); if(queues.size() > 0) { while(!queues.empty()) { RepositoryQueue &q = queues.front(); char cmd[256]; sprintf(cmd, "svnadmin create /home/svn/%s/%s/%s", q.GetPublicStatus().c_str(), q.GetUsername().c_str(), q.GetRepositoryName().c_str()); if(this->DeleteQueuedRepository(q.GetQueueId())) { printf("query deleted?\n"); } printf("Repository created!\n"); queues.pop(); } } boost::this_thread::sleep(boost::posix_time::milliseconds(500)); //} } protected: /** * Gets the latest queue of repositories from the database * and returns them inside a cool queue defined with the * RepositoryQueue class. */ std::queue<RepositoryQueue> GetQueue() { std::queue<RepositoryQueue> queues; Query query = this->_con.query("CALL sp_GetRepositoryQueue();"); StoreQueryResult result = query.store(); RepositoryQueue rQ; if(result.num_rows() > 0) { for(unsigned int i = 0;i < result.num_rows(); ++i) { rQ = RepositoryQueue((unsigned int)result[i][0], (unsigned int)result[i][1], (String)result[i][2], (String)result[i][3], (String)result[i][4], (bool)result[i][5]); queues.push(rQ); } } return queues; } /** * Allows the thread to be shut off. */ void ChangeRunningState(bool isRunning) { this->_isRunning = isRunning; } /** * Returns the running value of the active thread. */ bool IsRunning() { return this->_isRunning; } /** * Deletes the repository from the mysql queue table. This is * only called once it has been created. */ bool DeleteQueuedRepository(unsigned int id) { char cmd[256]; sprintf(cmd, "DELETE FROM RepositoryQueue WHERE Id = %d LIMIT 1;", id); Query query = this->_con.query(cmd); return (query.exec()); } }; I've removed all the other methods as they're not needed... Basically it's the DeleteQueuedRepository method which isn't working, the GetQueue works fine. PS: This is on a Linux OS (Ubuntu server) Many thanks, Shaun

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• use .net webbrowser control by multithread, throw "EXCEPTION code=ACCESS_VIOLATION"

  - by user1507827

  i want to make a console program to monitor a webpage's htmlsourcecode, because some of the page content are created by some javescript, so i have to use webbrowser control. like : View Generated Source (After AJAX/JavaScript) in C# my code is below: public class WebProcessor { public string GeneratedSource; public string URL ; public DateTime beginTime; public DateTime endTime; public object GetGeneratedHTML(object url) { URL = url.ToString(); try { Thread[] t = new Thread[10]; for (int i = 0; i < 10; i++) { t[i] = new Thread(new ThreadStart(WebBrowserThread)); t[i].SetApartmentState(ApartmentState.STA); t[i].Name = "Thread" + i.ToString(); t[i].Start(); //t[i].Join(); } } catch (Exception ex) { Console.WriteLine(ex.ToString()); } return GeneratedSource; } private void WebBrowserThread() { WebBrowser wb = new WebBrowser(); wb.ScriptErrorsSuppressed = true; wb.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler( wb_DocumentCompleted); while(true ) { beginTime = DateTime.Now; wb.Navigate(URL); while (wb.ReadyState != WebBrowserReadyState.Complete) { Thread.Sleep(new Random().Next(10,100)); Application.DoEvents(); } } //wb.Dispose(); } private void wb_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) { WebBrowser wb = (WebBrowser)sender; if (wb.ReadyState == WebBrowserReadyState.Complete) { GeneratedSource= wb.Document.Body.InnerHtml; endTime = DateTime.Now; Console.WriteLine("WebBrowser " + (endTime-beginTime).Milliseconds + Thread.CurrentThread.Name + wb.Document.Title); } } } when it run, after a while (20-50 times), it throw the exception like this EXCEPTION code=ACCESS_VIOLATION (null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(nul l)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(n ull)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null) (null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(null)(nul l)(null)BACKTRACE: 33 stack frames: #0 0x083dba8db0 at MatchExactGetIDsOfNames in mshtml.dll #1 0x0879f9b837 at StrongNameErrorInfo in mscorwks.dll #2 0x0879f9b8e3 at StrongNameErrorInfo in mscorwks.dll #3 0x0879f9b93a at StrongNameErrorInfo in mscorwks.dll #4 0x0879f9b9e0 at StrongNameErrorInfo in mscorwks.dll #5 0x0879f9b677 at StrongNameErrorInfo in mscorwks.dll #6 0x0879f9b785 at StrongNameErrorInfo in mscorwks.dll #7 0x0879f192a8 at InstallCustomModule in mscorwks.dll #8 0x0879f19444 at InstallCustomModule in mscorwks.dll #9 0x0879f194ab at InstallCustomModule in mscorwks.dll #10 0x0879fa6491 at StrongNameErrorInfo in mscorwks.dll #11 0x0879f44bcf at DllGetClassObjectInternal in mscorwks.dll #12 0x089bbafa at in #13 0x087b18cc10 at in System.Windows.Forms.ni.dll #14 0x087b91f4c1 at in System.Windows.Forms.ni.dll #15 0x08d00669 at in #16 0x08792d6e46 at in mscorlib.ni.dll #17 0x08792e02cf at in mscorlib.ni.dll #18 0x08792d6dc4 at in mscorlib.ni.dll #19 0x0879e71b4c at in mscorwks.dll #20 0x0879e896ce at in mscorwks.dll #21 0x0879e96ea9 at CoUninitializeEE in mscorwks.dll #22 0x0879e96edc at CoUninitializeEE in mscorwks.dll #23 0x0879e96efa at CoUninitializeEE in mscorwks.dll #24 0x0879f88357 at GetPrivateContextsPerfCounters in mscorwks.dll #25 0x0879e9cc8f at CoUninitializeEE in mscorwks.dll #26 0x0879e9cc2b at CoUninitializeEE in mscorwks.dll #27 0x0879e9cb51 at CoUninitializeEE in mscorwks.dll #28 0x0879e9ccdd at CoUninitializeEE in mscorwks.dll #29 0x0879f88128 at GetPrivateContextsPerfCounters in mscorwks.dll #30 0x0879f88202 at GetPrivateContextsPerfCounters in mscorwks.dll #31 0x0879f0e255 at InstallCustomModule in mscorwks.dll #32 0x087c80b729 at GetModuleFileNameA in KERNEL32.dll i have try lots of methods to solve the problem, finally, i found that if i thread sleep more millseconds, it will run for a longer time, but the exception is still throw. hope somebody give me the answer of how to slove ... thanks very much !!!

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• Android: Programatically Add UI Elements to a View

  - by Shivan Raptor

  My view is written as follow: package com.mycompany; import android.view.View; import java.util.concurrent.TimeUnit; import java.util.ArrayList; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.util.AttributeSet; import android.graphics.Paint; import android.graphics.Point; import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; import android.widget.*; public class GameEngineView extends View implements SensorEventListener { GameLoop gameloop; String txt_acc; float accY; ArrayList<Point> bugPath; private SensorManager sensorManager; private class GameLoop extends Thread { private volatile boolean running = true; public void run() { while (running) { try { TimeUnit.MILLISECONDS.sleep(1); postInvalidate(); pause(); } catch (InterruptedException ex) { running = false; } } } public void pause() { running = false; } public void start() { running = true; run(); } public void safeStop() { running = false; interrupt(); } } public void unload() { gameloop.safeStop(); } public GameEngineView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); // TODO Auto-generated constructor stub init(context); } public GameEngineView(Context context, AttributeSet attrs) { super(context, attrs); // TODO Auto-generated constructor stub init(context); } public GameEngineView(Context context) { super(context); // TODO Auto-generated constructor stub init(context); } private void init(Context context) { txt_acc = ""; // Adding SENSOR sensorManager=(SensorManager)context.getSystemService(Context.SENSOR_SERVICE); // add listener. The listener will be HelloAndroid (this) class sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL); // Adding UI Elements : How ? Button btn_camera = new Button(context); btn_camera.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.FILL_PARENT)); btn_camera.setClickable(true); btn_camera.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { System.out.println("clicked the camera."); } }); gameloop = new GameLoop(); gameloop.run(); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { // TODO Auto-generated method stub //super.onMeasure(widthMeasureSpec, heightMeasureSpec); System.out.println("Width " + widthMeasureSpec); setMeasuredDimension(widthMeasureSpec, heightMeasureSpec); } @Override protected void onDraw(Canvas canvas) { // TODO Auto-generated method stub // super.onDraw(canvas); Paint p = new Paint(); p.setColor(Color.WHITE); p.setStyle(Paint.Style.FILL); p.setAntiAlias(true); p.setTextSize(30); canvas.drawText("|[ " + txt_acc + " ]|", 50, 500, p); gameloop.start(); } public void onAccuracyChanged(Sensor sensor,int accuracy){ } public void onSensorChanged(SensorEvent event){ if(event.sensor.getType()==Sensor.TYPE_ACCELEROMETER){ //float x=event.values[0]; accY =event.values[1]; //float z=event.values[2]; txt_acc = "" + accY; } } } I would like to add a Button to the scene, but I don't know how to. Can anybody give me some lights? UPDATE: Here is my Activity : public class MyActivity extends Activity { private GameEngineView gameEngine; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // add Game Engine gameEngine = new GameEngineView(this); setContentView(gameEngine); gameEngine.requestFocus(); } }

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• Help with Silverlight Sockets and Message delivery

  - by pixel3cs

  There are 4 months since I stopped developing my Silverlight Multiplayer Chess game. The problem was a bug wich I couldn't reproduce. Sice I got some free time this week I managed to discover the problem and I am now able to reproduce the bug. It seems that if I send 10 messages from client, one after another, with no delay between them, just like in the below example // when I press Enter, the client will 10 messages with no delay between them private void textBox_KeyDown(object sender, KeyEventArgs e) { if (e.Key == Key.Enter && textBox.Text.Length > 0) { for (int i = 0; i < 10; i++) { MessageBuilder mb = new MessageBuilder(); mb.Writer.Write((byte)GameCommands.NewChatMessageInTable); mb.Writer.Write(string.Format("{0}{2}: {1}", ClientVars.PlayerNickname, textBox.Text, i)); SendChatMessageEvent(mb.GetMessage()); //System.Threading.Thread.Sleep(100); } textBox.Text = string.Empty; } } // the method used by client to send a message to server public void SendData(Message message) { if (socket.Connected) { SocketAsyncEventArgs myMsg = new SocketAsyncEventArgs(); myMsg.RemoteEndPoint = socket.RemoteEndPoint; byte[] buffer = message.Buffer; myMsg.SetBuffer(buffer, 0, buffer.Length); socket.SendAsync(myMsg); } else { string err = "Server does not respond. You are disconnected."; socket.Close(); uiContext.Post(this.uiClient.ProcessOnErrorData, err); } } // the method used by server to receive data from client private void OnDataReceived(IAsyncResult async) { ClientSocketPacket client = async.AsyncState as ClientSocketPacket; int count = 0; try { if (client.Socket.Connected) count = client.Socket.EndReceive(async); // THE PROBLEM IS HERE // IF SERVER WAS RECEIVE ALL MESSAGES SEPARATELY, ONE BY ONE, THE COUNT // WAS ALWAYS 15, BUT BECAUSE THE SERVER RECEIVE 3 MESSAGES IN 1, THE COUNT // IS SOMETIME 45 } catch { HandleException(client); } client.MessageStream.Write(client.Buffer, 0, count); Message message; while (client.MessageStream.Read(out message)) { message.Tag = client; ThreadPool.QueueUserWorkItem(new WaitCallback(this.processingThreadEvent.ServerGotData), message); totalReceivedBytes += message.Buffer.Length; } try { if (client.Socket.Connected) client.Socket.BeginReceive(client.Buffer, 0, client.Buffer.Length, 0, new AsyncCallback(OnDataReceived), client); } catch { HandleException(client); } } there are sent only 3 big messages, and every big message contain 3 or 4 small messages. This is not the behavior I want. If I put a 100 milliseconds delay between message delivery, everything is work fine, but in a real world scenario users can send messages to server even at 1 millisecond between them. Are there any settings to be done in order to make the client send only one message at a time, or Even if I receive 3 messages in 1, are they full messages all the time (I dont't want to receive 2.5 messages in one big message) ? because if they are, I can read them and treat this new situation

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• Problems with blocking reads using libudev on Linux

  - by Steve Hawkins

  We are using the following routine (on Linux, with libudev) to read data from a PIC microcontroller configured as a USB HID device. The data is sent only when a button connected to the PIC microcontroller is pressed or released. The routine is missing messages from the PIC controller, and I suspect that this is because the call to poll below is not behaving as it should. The call to poll will reliably block for 1 second util the first message is read. As soon as the first message is read, the call to poll returns immediately instead of blocking for 1 second (1000 milliseconds) like it should. I have worked around this problem by closing and re-opening the device after each read. This makes poll behave correctly, but I think that closing and re-opening the device may be the reason for the lost messages. bool PicIo::Receive (unsigned char* picData, const size_t picDataSize) { static hiddev_report_info hidReportInfo; static hiddev_usage_ref_multi hidUsageRef; if (-1 == PicDeviceDescriptor()) { return false; } // Determine whether or not there is data available to be read pollfd pollFd; pollFd.fd = PicDeviceDescriptor(); pollFd.events = POLLIN; int dataPending = poll (&pollFd, 1, 1000); if (dataPending <= 0) { return false; } // Initialize the HID Report structure for an input report hidReportInfo.report_type = HID_REPORT_TYPE_INPUT; hidReportInfo.report_id = 0; hidReportInfo.num_fields = 64; if (-1 == ioctl(PicDeviceDescriptor(), HIDIOCGREPORT, &hidReportInfo)) { return false; } // Initizlize the HID Usage Reference for an Input report hidUsageRef.uref.report_type = HID_REPORT_TYPE_INPUT; hidUsageRef.uref.report_id = 0; hidUsageRef.uref.field_index = 0; hidUsageRef.uref.usage_index = 0; hidUsageRef.num_values = 64; if (-1 == ioctl(PicDeviceDescriptor(), HIDIOCGUSAGES, &hidUsageRef)) { return false; } // Transfer bytes from the usage report into the return value. for (size_t idx=0; (idx < 64) && (idx < picDataSize); ++idx) { picData[idx] = hidUsageRef.values[idx]; } return true; } The function PicDeviceDescriptor() does checking on the device to make sure that it is present. Here are the pertinent details of the PicDeviceDescriptor function, showing how the device is begin opened. int PicIo::PicDeviceDescriptor(int command) { struct stat statInfo; static int picDeviceDescriptor = -1; string picDevicePath = "/dev/usb/hiddev0"; if ((-1 != picDeviceDescriptor) && (CLOSE == command)) { close (picDeviceDescriptor); picDeviceDescriptor = -1; } else if ((-1 != picDeviceDescriptor) && (-1 == fstat(picDeviceDescriptor, &statInfo))) { // Handle the case where the PIC device had previously been detected, and // is now disconnected. close (picDeviceDescriptor); picDeviceDescriptor = -1; } else if ((-1 == picDeviceDescriptor) && (m_picDevice.IsConnected())) { // Create the PIC device descriptor if the PIC device is present (i.e. its // device node is present) and if the descriptor does not already exist picDeviceDescriptor = open (picDevicePath.c_str(), O_RDONLY); } return picDeviceDescriptor; } I'm sure that I'm doing something wrong, but I've Googled the issue and cannot seem to find any relevant answers. Any help would be very much appreciated -- Thx.

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• Weird GWT issue causing IE threads to skyrocket.

  - by WesleyJohnson

  I'm not sure if this is an issue with GWT, JavaScript, Java, IE or just poor programming, but I'll try to explain. We're implementing web based chat program at work and some of our users have unreliable connections. So we're running into issues where they send out a new message and after x number of milliseconds have passed, the XHR request timesout and the client tries to resend the message again. The issue we ran into was sometimes the message would make it to the server and into the DB, but the XHR request wouldn't make it back to the client so the client was essentially retrying requests that had alread made it to the server. To mitigate this issue, we now send along a count/key with the message. The client says, hey I'm sending msg 50 and it's text is this. If the server already has that message, it just sends back "ok, I got it" and doens't insert into the DB again, eliminating dupes. So the client is free to keep retrying over and over until finally a call comes back from the server saying "Ok, I got it" and then it increments the key and moves on (or we keep them out of the chat if it fails enough). Anyway, so that's the background of what we're doing. The issue is, when we add this code on some versions of IE the threads start increasing gradually everytime it's accessed. On IE8 for Windows7 x64 it doesn't really seem to do it, but on IE8 for Windows Vista x86 it does. So I can't really pinpoint if it's a fluke or my code. Maybe someone had some ideas on a better way to do this. Here is some pseudo code: (the issue seems appear where I increment messageCount? Is this a scope thing, naming conflict, maybe the issue is entirely somewhere else and I'm way off base. public class SFChatClient implements EntryPoint { private List<String> messageQueue; private Integer messageCount = 0; public void onModuleLoad() { messageQueue = new ArrayList<String>(); // setup ui and what not // add a keyhandler to an input box that checks for <ENTER> and calls sendMEssage() } private void sendMessage() { // add message content to the UI for the chat messageQueue.add( //get message from user ); sendQueuedMessages(); } private void sendQueuedMessages() { if( messageQueue.size() > 0 ) { String outgoingMessage = messageQueue.get( 0 ); WebServiceClass.sendMessage( outgoingMessage, messageCount, new WebServiceHandler() { public void onSuccess() { // Delete item 0 from messageQueue messageCount = messageCount + 1; // <--- this seems to cause IE to leak threads. Taking out this code stops the issue??? sendQueuedMessages(); } public void onError() { // Do error handling sendQueuedMessages(); } } ); } } } public class WebServiceClass() { public void sendMessage( String message, Integer messageCount, handler ) { RequestBuilder builder = new RequestBuilder(// create request builder with proper params for the web service url, JSON content type, etc ) { public void onSuccess() { handler.onSuccess() } public void onError() { handler.onError() } } builder.setData( // JSON with message ); bulder.send(); } }

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• HMTL5 Anti Aliasing Browser Disable

  - by Tappa Tappa

  I am forced to consider writing a library to handle the fundamental basics of drawing lines, thick lines, circles, squares etc. of an HTML5 canvas because I can't disable a feature embedded in the browser rendering of the core canvas algorithms. Am I forced to build the HTML5 Canvas rendering process from the ground up? If I am, who's in with me to do this? Who wants to change the world? Imagine a simple drawing application written in HTML5... you draw a shape... a closed shape like a rudimentary circle, free hand, more like an onion than a circle (well, that's what mine would look like!)... then imagine selecting a paint bucket icon and clicking inside that shape you drew and expecting it to be filled with a color of your choice. Imagine your surprise as you selected "Paint Bucket" and clicked in the middle of your shape and it filled your shape with color... BUT, not quite... HANG ON... this isn't right!!! On the inside of the edge of the shape you drew is a blur between the background color and your fill color and the edge color... the fill seems to be flawed. You wanted a straight forward "Paint Bucket" / "Fill"... you wanted to draw a shape and then fill it with a color... no fuss.... fill the whole damned inside of your shape with the color you choose. Your web browser has decided that when you draw the lines to define your shape they will be anti-aliased. If you draw a black line for your shape... well, the browser will draw grey pixels along the edges, in places... to make it look like a "better" line. Yeah, a "better" line that **s up the paint / flood fill process. How much does is cost to pay off the browser developers to expose a property to disable their anti-aliasing rendering? Disabling would save milliseconds for their rendering engine, surely! Bah, I really don't want to have to build my own canvas rendering engine using Bresenham line rendering algorithm... WHAT CAN BE DONE... HOW CAN THIS BE CHANGED!!!??? Do I need to start a petition aimed at the WC3???? Will you include your name if you are interested??? UPDATED function DrawLine(objContext, FromX, FromY, ToX, ToY) { var dx = Math.abs(ToX - FromX); var dy = Math.abs(ToY - FromY); var sx = (FromX < ToX) ? 1 : -1; var sy = (FromY < ToY) ? 1 : -1; var err = dx - dy; var CurX, CurY; CurX = FromX; CurY = FromY; while (true) { objContext.fillRect(CurX, CurY, objContext.lineWidth, objContext.lineWidth); if ((CurX == ToX) && (CurY == ToY)) break; var e2 = 2 * err; if (e2 > -dy) { err -= dy; CurX += sx; } if (e2 < dx) { err += dx; CurY += sy; } } }

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• 10000's+ UI elements, bind or draw?

  - by jpiccolo

  I am drawing a header for a timeline control. It looks like this: I go to 0.01 millisecond per line, so for a 10 minute timeline I am looking at drawing 60000 lines + 6000 labels. This takes a while, ~10 seconds. I would like to offload this from the UI thread. My code is currently: private void drawHeader() { Header.Children.Clear(); switch (viewLevel) { case ViewLevel.MilliSeconds100: double hWidth = Header.Width; this.drawHeaderLines(new TimeSpan(0, 0, 0, 0, 10), 100, 5, hWidth); //Was looking into background worker to off load UI //backgroundWorker = new BackgroundWorker(); //backgroundWorker.DoWork += delegate(object sender, DoWorkEventArgs args) // { // this.drawHeaderLines(new TimeSpan(0, 0, 0, 0, 10), 100, 5, hWidth); // }; //backgroundWorker.RunWorkerAsync(); break; } } private void drawHeaderLines(TimeSpan timeStep, int majorEveryXLine, int distanceBetweenLines, double headerWidth) { var currentTime = new TimeSpan(0, 0, 0, 0, 0); const int everyXLine100 = 10; double currentX = 0; var currentLine = 0; while (currentX < headerWidth) { var l = new Line { ToolTip = currentTime.ToString(@"hh\:mm\:ss\.fff"), StrokeThickness = 1, X1 = 0, X2 = 0, Y1 = 30, Y2 = 25 }; if (((currentLine % majorEveryXLine) == 0) && currentLine != 0) { l.StrokeThickness = 2; l.Y2 = 15; var textBlock = new TextBlock { Text = l.ToolTip.ToString(), FontSize = 8, FontFamily = new FontFamily("Tahoma"), Foreground = new SolidColorBrush(Color.FromRgb(255, 255, 255)) }; Canvas.SetLeft(textBlock, (currentX - 22)); Canvas.SetTop(textBlock, 0); Header.Children.Add(textBlock); } if ((((currentLine % everyXLine100) == 0) && currentLine != 0) && (currentLine % majorEveryXLine) != 0) { l.Y2 = 20; var textBlock = new TextBlock { Text = string.Format(".{0}", TimeSpan.Parse(l.ToolTip.ToString()).Milliseconds), FontSize = 8, FontFamily = new FontFamily("Tahoma"), Foreground = new SolidColorBrush(Color.FromRgb(192, 192, 192)) }; Canvas.SetLeft(textBlock, (currentX - 8)); Canvas.SetTop(textBlock, 8); Header.Children.Add(textBlock); } l.Stroke = new SolidColorBrush(Color.FromRgb(255, 255, 255)); Header.Children.Add(l); Canvas.SetLeft(l, currentX); currentX += distanceBetweenLines; currentLine++; currentTime += timeStep; } } I had looked into BackgroundWorker, except you can't create UI elements on a non-UI thread. Is it possible at all to do drawHeaderLines in a non-UI thread? Could I use data binding for drawing the lines? Would this help with UI responsiveness? I would imagine I can use databinding, but the Styling is probably beyond my current WPF ability (coming from winforms and trying to learn what all these style objects are and binding them). Would anyone be able to supply a starting point for tempting this out? Or Google a tutorial that would get me started?

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