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• Coding error at open URL

  - by Lobo

  Hi, I have the following method to open a URL API String c=""; URL direccionURL; try { direccionURL = new URL("http://api.stackoverflow.com/1.0/users/523725"); BufferedReader in = new BufferedReader(new InputStreamReader( direccionURL.openStream())); String inputLine; while ((inputLine = in.readLine()) != null) c+=inputLine; in.close(); } catch (MalformedURLException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return c; In the end, the "c" variable contains a set of characters that are not the same I get if I open the same URL with a browser. Why?, What am I doing wrong? Thank's for help. Regards!

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• What is the most efficient way to convert to binary and back in C#?

  - by Saad Imran.

  I'm trying to write a general purpose socket server for a game I'm working on. I know I could very well use already built servers like SmartFox and Photon, but I wan't to go through the pain of creating one myself for learning purposes. I've come up with a BSON inspired protocol to convert the the basic data types, their arrays, and a special GSObject to binary and arrange them in a way so that it can be put back together into object form on the client end. At the core, the conversion methods utilize the .Net BitConverter class to convert the basic data types to binary. Anyways, the problem is performance, if I loop 50,000 times and convert my GSObject to binary each time it takes about 5500ms (the resulting byte[] is just 192 bytes per conversion). I think think this would be way too slow for an MMO that sends 5-10 position updates per second with a 1000 concurrent users. Yes, I know it's unlikely that a game will have a 1000 users on at the same time, but like I said earlier this is supposed to be a learning process for me, I want to go out of my way and build something that scales well and can handle at least a few thousand users. So yea, if anyone's aware of other conversion techniques or sees where I'm loosing performance I would appreciate the help. GSBitConverter.cs This is the main conversion class, it adds extension methods to main datatypes to convert to the binary format. It uses the BitConverter class to convert the base types. I've shown only the code to convert integer and integer arrays, but the rest of the method are pretty much replicas of those two, they just overload the type. public static class GSBitConverter { public static byte[] ToGSBinary(this short value) { return BitConverter.GetBytes(value); } public static byte[] ToGSBinary(this IEnumerable<short> value) { List<byte> bytes = new List<byte>(); short length = (short)value.Count(); bytes.AddRange(length.ToGSBinary()); for (int i = 0; i < length; i++) bytes.AddRange(value.ElementAt(i).ToGSBinary()); return bytes.ToArray(); } public static byte[] ToGSBinary(this bool value); public static byte[] ToGSBinary(this IEnumerable<bool> value); public static byte[] ToGSBinary(this IEnumerable<byte> value); public static byte[] ToGSBinary(this int value); public static byte[] ToGSBinary(this IEnumerable<int> value); public static byte[] ToGSBinary(this long value); public static byte[] ToGSBinary(this IEnumerable<long> value); public static byte[] ToGSBinary(this float value); public static byte[] ToGSBinary(this IEnumerable<float> value); public static byte[] ToGSBinary(this double value); public static byte[] ToGSBinary(this IEnumerable<double> value); public static byte[] ToGSBinary(this string value); public static byte[] ToGSBinary(this IEnumerable<string> value); public static string GetHexDump(this IEnumerable<byte> value); } Program.cs Here's the the object that I'm converting to binary in a loop. class Program { static void Main(string[] args) { GSObject obj = new GSObject(); obj.AttachShort("smallInt", 15); obj.AttachInt("medInt", 120700); obj.AttachLong("bigInt", 10900800700); obj.AttachDouble("doubleVal", Math.PI); obj.AttachStringArray("muppetNames", new string[] { "Kermit", "Fozzy", "Piggy", "Animal", "Gonzo" }); GSObject apple = new GSObject(); apple.AttachString("name", "Apple"); apple.AttachString("color", "red"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)1.5); GSObject lemon = new GSObject(); apple.AttachString("name", "Lemon"); apple.AttachString("color", "yellow"); apple.AttachBool("inStock", false); apple.AttachFloat("price", (float)0.8); GSObject apricoat = new GSObject(); apple.AttachString("name", "Apricoat"); apple.AttachString("color", "orange"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)1.9); GSObject kiwi = new GSObject(); apple.AttachString("name", "Kiwi"); apple.AttachString("color", "green"); apple.AttachBool("inStock", true); apple.AttachFloat("price", (float)2.3); GSArray fruits = new GSArray(); fruits.AddGSObject(apple); fruits.AddGSObject(lemon); fruits.AddGSObject(apricoat); fruits.AddGSObject(kiwi); obj.AttachGSArray("fruits", fruits); Stopwatch w1 = Stopwatch.StartNew(); for (int i = 0; i < 50000; i++) { byte[] b = obj.ToGSBinary(); } w1.Stop(); Console.WriteLine(BitConverter.IsLittleEndian ? "Little Endian" : "Big Endian"); Console.WriteLine(w1.ElapsedMilliseconds + "ms"); } Here's the code for some of my other classes that are used in the code above. Most of it is repetitive. GSObject GSArray GSWrappedObject

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• Parallelism in .NET – Part 17, Think Continuations, not Callbacks

  - by Reed

  In traditional asynchronous programming, we’d often use a callback to handle notification of a background task’s completion.  The Task class in the Task Parallel Library introduces a cleaner alternative to the traditional callback: continuation tasks. Asynchronous programming methods typically required callback functions.  For example, MSDN’s Asynchronous Delegates Programming Sample shows a class that factorizes a number.  The original method in the example has the following signature: public static bool Factorize(int number, ref int primefactor1, ref int primefactor2) { //... .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } However, calling this is quite “tricky”, even if we modernize the sample to use lambda expressions via C# 3.0.  Normally, we could call this method like so: int primeFactor1 = 0; int primeFactor2 = 0; bool answer = Factorize(10298312, ref primeFactor1, ref primeFactor2); Console.WriteLine("{0}/{1} [Succeeded {2}]", primeFactor1, primeFactor2, answer); If we want to make this operation run in the background, and report to the console via a callback, things get tricker.  First, we need a delegate definition: public delegate bool AsyncFactorCaller( int number, ref int primefactor1, ref int primefactor2); Then we need to use BeginInvoke to run this method asynchronously: int primeFactor1 = 0; int primeFactor2 = 0; AsyncFactorCaller caller = new AsyncFactorCaller(Factorize); caller.BeginInvoke(10298312, ref primeFactor1, ref primeFactor2, result => { int factor1 = 0; int factor2 = 0; bool answer = caller.EndInvoke(ref factor1, ref factor2, result); Console.WriteLine("{0}/{1} [Succeeded {2}]", factor1, factor2, answer); }, null); This works, but is quite difficult to understand from a conceptual standpoint.  To combat this, the framework added the Event-based Asynchronous Pattern, but it isn’t much easier to understand or author. Using .NET 4’s new Task<T> class and a continuation, we can dramatically simplify the implementation of the above code, as well as make it much more understandable.  We do this via the Task.ContinueWith method.  This method will schedule a new Task upon completion of the original task, and provide the original Task (including its Result if it’s a Task<T>) as an argument.  Using Task, we can eliminate the delegate, and rewrite this code like so: var background = Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }); background.ContinueWith(task => Console.WriteLine("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result)); This is much simpler to understand, in my opinion.  Here, we’re explicitly asking to start a new task, then continue the task with a resulting task.  In our case, our method used ref parameters (this was from the MSDN Sample), so there is a little bit of extra boiler plate involved, but the code is at least easy to understand. That being said, this isn’t dramatically shorter when compared with our C# 3 port of the MSDN code above.  However, if we were to extend our requirements a bit, we can start to see more advantages to the Task based approach.  For example, supposed we need to report the results in a user interface control instead of reporting it to the Console.  This would be a common operation, but now, we have to think about marshaling our calls back to the user interface.  This is probably going to require calling Control.Invoke or Dispatcher.Invoke within our callback, forcing us to specify a delegate within the delegate.  The maintainability and ease of understanding drops.  However, just as a standard Task can be created with a TaskScheduler that uses the UI synchronization context, so too can we continue a task with a specific context.  There are Task.ContinueWith method overloads which allow you to provide a TaskScheduler.  This means you can schedule the continuation to run on the UI thread, by simply doing: Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }).ContinueWith(task => textBox1.Text = string.Format("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result), TaskScheduler.FromCurrentSynchronizationContext()); This is far more understandable than the alternative.  By using Task.ContinueWith in conjunction with TaskScheduler.FromCurrentSynchronizationContext(), we get a simple way to push any work onto a background thread, and update the user interface on the proper UI thread.  This technique works with Windows Presentation Foundation as well as Windows Forms, with no change in methodology.

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• The ugly evolution of running a background operation in the context of an ASP.NET app

  - by Jeff

  If you’re one of the two people who has followed my blog for many years, you know that I’ve been going at POP Forums now for over almost 15 years. Publishing it as an open source app has been a big help because it helps me understand how people want to use it, and having it translated to six languages is pretty sweet. Despite this warm and fuzzy group hug, there has been an ugly hack hiding in there for years. One of the things we find ourselves wanting to do is hide some kind of regular process inside of an ASP.NET application that runs periodically. The motivation for this has always been that a lot of people simply don’t have a choice, because they’re running the app on shared hosting, or don’t otherwise have access to a box that can run some kind of regular background service. In POP Forums, I “solved” this problem years ago by hiding some static timers in an HttpModule. Truthfully, this works well as long as you don’t run multiple instances of the app, which in the cloud world, is always a possibility. With the arrival of WebJobs in Azure, I’m going to solve this problem. This post isn’t about that. The other little hacky problem that I “solved” was spawning a background thread to queue emails to subscribed users of the forum. This evolved quite a bit over the years, starting with a long running page to mail users in real-time, when I had only a few hundred. By the time it got into the thousands, or tens of thousands, I needed a better way. What I did is launched a new thread that read all of the user data in, then wrote a queued email to the database (as in, the entire body of the email, every time), with the properly formatted opt-out link. It was super inefficient, but it worked. Then I moved my biggest site using it, CoasterBuzz, to an Azure Website, and it stopped working. So let’s start with the first stupid thing I was doing. The new thread was simply created with delegate code inline. As best I can tell, Azure Websites are more aggressive about garbage collection, because that thread didn’t queue even one message. When the calling server response went out of scope, so went the magic background thread. Duh, all I had to do was move the thread to a private static variable in the class. That’s the way I was able to keep stuff running from the HttpModule. (And yes, I know this is still prone to failure, particularly if the app recycles. For as infrequently as it’s used, I have not, however, experienced this.) It was still failing, but this time I wasn’t sure why. It would queue a few dozen messages, then die. Running in Azure, I had to turn on the application logging and FTP in to see what was going on. That led me to a helper method I was using as delegate to build the unsubscribe links. The idea here is that I didn’t want yet another config entry to describe the base URL, appended with the right path that would match the routing table. No, I wanted the app to figure it out for you, so I came up with this little thing: public static string FullUrlHelper(this Controller controller, string actionName, string controllerName, object routeValues = null) { var helper = new UrlHelper(controller.Request.RequestContext); var requestUrl = controller.Request.Url; if (requestUrl == null) return String.Empty; var url = requestUrl.Scheme + "://"; url += requestUrl.Host; url += (requestUrl.Port != 80 ? ":" + requestUrl.Port : ""); url += helper.Action(actionName, controllerName, routeValues); return url; } And yes, that should have been done with a string builder. This is useful for sending out the email verification messages, too. As clever as I thought I was with this, I was using a delegate in the admin controller to format these unsubscribe links for tens of thousands of users. I passed that delegate into a service class that did the email work: Func<User, string> unsubscribeLinkGenerator = user => this.FullUrlHelper("Unsubscribe", AccountController.Name, new { id = user.UserID, key = _profileService.GetUnsubscribeHash(user) }); _mailingListService.MailUsers(subject, body, htmlBody, unsubscribeLinkGenerator); Cool, right? Actually, not so much. If you look back at the helper, this delegate then will depend on the controller context to learn the routing and format for the URL. As you might have guessed, those things were turning null after a few dozen formatted links, when the original request to the admin controller went away. That this wasn’t already happening on my dedicated server is surprising, but again, I understand why the Azure environment might be eager to reclaim a thread after servicing the request. It’s already inefficient that I’m building the entire email for every user, but going back to check the routing table for the right link every time isn’t a win either. I put together a little hack to look up one generic URL, and use that as the basis for a string format. If you’re wondering why I didn’t just use the curly braces up front, it’s because they get URL formatted: var baseString = this.FullUrlHelper("Unsubscribe", AccountController.Name, new { id = "--id--", key = "--key--" }); baseString = baseString.Replace("--id--", "{0}").Replace("--key--", "{1}"); Func unsubscribeLinkGenerator = user => String.Format(baseString, user.UserID, _profileService.GetUnsubscribeHash(user)); _mailingListService.MailUsers(subject, body, htmlBody, unsubscribeLinkGenerator); And wouldn’t you know it, the new solution works just fine. It’s still kind of hacky and inefficient, but it will work until this somehow breaks too.

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• SQL SERVER – Weekly Series – Memory Lane – #005

  - by pinaldave

  Here is the list of curetted articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 SQL SERVER – Cursor to Kill All Process in Database I indeed wrote this cursor and when I often look back, I wonder how naive I was to write this. The reason for writing this cursor was to free up my database from any existing connection so I can do database operation. This worked fine but there can be a potentially big issue if there was any important transaction was killed by this process. There is another way to to achieve the same thing where we can use ALTER syntax to take database in single user mode. Read more about that over here and here. 2007 Rules of Third Normal Form and Normalization Advantage – 3NF The rules of 3NF are mentioned here Make a separate table for each set of related attributes, and give each table a primary key. If an attribute depends on only part of a multi-valued key, remove it to a separate table If attributes do not contribute to a description of the key, remove them to a separate table. Correct Syntax for Stored Procedure SP Sometime a simple question is the most important question. I often see in industry incorrectly written Stored Procedure. Few writes code after the most outer BEGIN…END and few writes code after the GO Statement. In this brief blog post, I have attempted to explain the same. 2008 Switch Between Result Pan and Query Pan – SQL Shortcut Many times when I am writing query I have to scroll the result displayed in the result set. Most of the developer uses the mouse to switch between and Query Pane and Result Pane. There are few developers who are crazy about Keyboard shortcuts. F6 is the keyword which can be used to switch between query pane and tabs of the result pane. Interesting Observation – Use of Index and Execution Plan Query Optimization is a complex game and it has its own rules. From the example in the article we have discovered that Query Optimizer does not use clustered index to retrieve data, sometime non clustered index provides optimal performance for retrieving Primary Key. When all the rows and columns are selected Primary Key should be used to select data as it provides optimal performance. 2009 Interesting Observation – TOP 100 PERCENT and ORDER BY If you pull up any application or system where there are more than 100 SQL Server Views are created – I am very confident that at one or two places you will notice the scenario wherein View the ORDER BY clause is used with TOP 100 PERCENT. SQL Server 2008 VIEW with ORDER BY clause does not throw an error; moreover, it does not acknowledge the presence of it as well. In this article we have taken three perfect examples and demonstrated which clause we should use when. Comma Separated Values (CSV) from Table Column A Very common question – How to create comma separated values from a table in the database? The answer is also very common if we use XML. Check out this article for quick learning on the same subject. Azure Start Guide – Step by Step Installation Guide Though Azure portal has changed a quite bit since I wrote this article, the concept used in this article are not old. They are still valid and many of the functions are still working as mentioned in the article. I believe this one article will put you on the track to use Azure! Size of Index Table for Each Index – Solution Earlier I have posted a small question on this blog and requested help from readers to participate here and provide a solution. The puzzle was to write a query that will return the size for each index that is on any particular table. We need a query that will return an additional column in the above listed query and it should contain the size of the index. This article presents two of the best solutions from the puzzle. 2010 Well, this week in 2010 was the week of puzzles as I posted three interesting puzzles. Till today I am noticing pretty good interesting in the puzzles. They are tricky but for sure brings a great value if you are a database developer for a long time. I suggest you go over this puzzles and their answers. Did you really know all of the answers? I am confident that reading following three blog post will for sure help you enhance the experience with T-SQL. SQL SERVER – Challenge – Puzzle – Usage of FAST Hint SQL SERVER – Puzzle – Challenge – Error While Converting Money to Decimal SQL SERVER – Challenge – Puzzle – Why does RIGHT JOIN Exists 2011 DVM sys.dm_os_sys_info Column Name Changed in SQL Server 2012 Have you ever faced a situation where something does not work? When you try to fix it - you enjoy fixing it and started to appreciate the breaking changes. Well, this was exactly I felt yesterday. Before I begin my story, I want to candidly state that I do not encourage anybody to use * in the SELECT statement. Now the disclaimer is over – I suggest you read the original story – you will love it! Get Directory Structure using Extended Stored Procedure xp_dirtree Here is the question to you – why would you do something in SQL Server where you can do the same task in command prompt much easily. Well, the answer is sometime there are real use cases when we have to do such thing. This is a similar example where I have demonstrated how in SQL Server 2012 we can use extended stored procedure to retrieve directory structure. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• GTK equivalent to MS Spy++

  - by zetah

  Spy++ comes with paid version of MS Visual Studio as utility that gives you a graphical view of the system’s processes, threads, windows, and window messages. and it's not only utility on Win32 that offers this feature, but I use it as popular example. It lists all UI elements of all running applications, and user can use "Find Tool" to locate UI element of interest and get response dialog with versatile information about that object, like UI control name, text contents, and many other data of potential interest to a programmer. I'm interested in similar GTK application which can at least return GTK UI element (widget) name and extracted text contents of that element of arbitrary running process. I couldn't find anything related using Google

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• How can I get objects and property values from expression trees?

  This is a follow-up to the Getting Information About Objects, Types, and Members with Expression Trees post, so I would recommend that you read that one first. Among other code examples in that blog post, I demonstrated how you can get a property name as a string by using expression trees. Here is the method. public static string GetName<T>(Expression<Func<T>> e) { var member = (MemberExpression)e.Body; return member.Member.Name; } And here is how you can use it. string...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• How can I get objects and property values from expression trees?

  This is a follow-up to the Getting Information About Objects, Types, and Members with Expression Trees post, so I would recommend that you read that one first. Among other code examples in that blog post, I demonstrated how you can get a property name as a string by using expression trees. Here is the method. public static string GetName<T>(Expression<Func<T>> e) { var member = (MemberExpression)e.Body; return member.Member.Name; } And here is how you can use it. string...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• SQL Authority News – Play by Play with Pinal Dave – A Birthday Gift

  - by Pinal Dave

  Today is my birthday. Personal Note When I was young, I was always looking forward to my birthday as on this day, I used to get gifts from everybody. Now when I am getting old on each of my birthday, I have almost same feeling but the direction is different. Now on each of my birthday, I feel like giving gifts to everybody. I have received lots of support, love and respect from everybody; and now I must return it back.Well, on this birthday, I have very unique gifts for everybody – my latest course on SQL Server. How I Tune Performance I often get questions where I am asked how do I work on a normal day. I am often asked that how do I work when I have performance tuning project is assigned to me. Lots of people have expressed their desire that they want me to explain and demonstrate my own method of solving performance problem when I am facing real world problem. It is a pretty difficult task as in the real world, nothing goes as planned and usually planned demonstrations have no place there. The real world, demands real solutions and in a timely fashion. If a consultant goes to industry and does not demonstrate his/her capabilities in very first few minutes, it does not matter how much fame he/she is, the door is shown to them eventually. It is true and in my early career, I have faced it quite commonly. I have learned the trick to be honest from the start and request absolutely transparent communication from the organization where I am to consult. Play by Play Play by Play is a very unique setup. It is not planned and it is a step by step course. It is like a reality show – a very real encounter to the problem and real problem solving approach. I had a great time doing this course. Geoffrey Grosenbach (VP of Pluralsight) sits down with me to see what a SQL Server Admin does in the real world. This Play-by-Play focuses on SQL Server performance tuning and I go over optimizing queries and fine-tuning the server. The table of content of this course is very simple. Introduction In the introduction I explained my basic strategies when I am approached by a customer for performance tuning. Basic Information Gathering In this module I explain how I do gather various information for performance tuning project. It is very crucial to demonstrate to customers for consultant his capability of solving problem. I attempt to resolve a small problem which gives a big positive impact on performance, consultant have to gather proper information from the start. I demonstrate in this module, how one can collect all the important performance tuning metrics. Removing Performance Bottleneck In this module, I build upon the previous module’s statistics collected. I analysis various performance tuning measures and immediately start implementing various tweaks on the performance, which will start improving the performance of my server. This is a very effective method and it gives immediate return of efforts. Index Optimization Indexes are considered as a silver bullet for performance tuning. However, it is not true always there are plenty of examples where indexes even performs worst after implemented. The key is to understand a few of the basic properties of the index and implement the right things at the right time. In this module, I describe in detail how to do index optimizations and what are right and wrong with Index. If you are a DBA or developer, and if your application is running slow – this is must attend module for you. I have some really interesting stories to tell as well. Optimize Query with Rewrite Every problem has more than one solution, in this module we will see another very famous, but hard to master skills for performance tuning – Query Rewrite. There are few do’s and don’ts for any query rewrites. I take a very simple example and demonstrate how query rewrite can improve the performance of the query at many folds. I also share some real world funny stories in this module. This course is hosted at Pluralsight. You will need a valid login for Pluralsight to watch  Play by Play: Pinal Dave course. You can also sign up for FREE Trial of Pluralsight to watch this course. As today is my birthday – I will give 10 people (randomly) who will express their desire to learn this course, a free code. Please leave your comment and I will send you free code to watch this course for free. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, SQLAuthority News, T SQL, Video

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• Legal question.

  - by Kjow

  Hi all, a question bounces in my head from some time. Copyright laws are different by nation to nation, but generally which is the border line to break a copyright? Suppose to make a game that is very similar to an other come out in the past, e.g. a Pacman clone or a Space Invaders clone, but nothing from original titles are grabbed and maybe they're not made in 2d, but in 3d. The titles aren't "Pacman clone - the return" or "Space Invaders - they did it again", and not also "Pocman" or "Space Evaders" (maybe this last could be fun for some "creative financers" that need to escape from earth :D). Finally suppose to call these some thing like "Popcorn, fruit and ghosts" (or the acronym: "PFG") and "Kill all enemy" (or the acronym: "KAE"). In this case (not grab- all self-made) and no references to original titles, but with a game that feels very similar to "ispiration ones"... they could be sold to somewhere like "Valve's Steam"? Regards, Kjow

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• Unique Business Value vs. Unique IT

  - by barry.perkins

  When the age of computing started, technology was new, exciting, full of potential and had a long way to grow. Vendor architectures were proprietary, and limited in function at first, growing in capability and complexity over time. There were few if any "standards", let alone "open standards" and the concepts of "open systems", and "open architectures" were far in the future. Companies employed intelligent, talented and creative people to implement the best possible solutions for their company. At first, those solutions were "unique" to each company. As time progressed, standards emerged, companies shared knowledge, business capability supplied by technology grew, and companies continued to expand their use of technology. Taking advantage of change required companies to struggle through periodic "revolutionary" change cycles, struggling through costly changes that were fraught with risk, resulted in solutions with an increasingly shorter half-life, and frequently required altering existing business processes and retraining employees and partner businesses. The pace of technological invention and implementation grew at an ever increasing rate, making the "revolutionary" approach based upon "proprietary" or "closed" architectures or technologies no longer viable. Concurrent with the advancement of technology, the rate of change in business increased, leading us to the incredibly fast paced, highly charged, and competitive global economy that we have today, where the most successful companies are companies that are good at implementing, leveraging and exploiting change. Fast forward to today, a world where dramatic changes in business and technology happen continually, a world where "evolutionary" change is crucial. Companies can no longer afford to build "unique IT", nor can they afford regular intervals of "revolutionary" change, with the associated costs and risks. Human ingenuity was once again up to the task, turning technology into a platform supporting business through evolutionary change, by employing "open": open standards; open systems; open architectures; and open solutions. Employing "open", enables companies to implement systems based upon technology, capability and standards that will evolve over time, providing a solid platform upon which a company can drive business needs, requirements, functions, and processes down into the technology, rather than exposing technology to the business, allowing companies to focus on providing "unique business value" rather than "unique IT". The big question! Does moving from "older" technology that no longer meets the needs of today's business, to new "open" technology require yet another "revolutionary change"? A "revolutionary" change with a short half-life, camouflaging reality with great marketing? The answer is "perhaps". With the endless options available to choose from, it is entirely possible to implement a solution that may work well today, but in 5 years time will become yet another albatross for the company to bear. Some solutions may look good today, solving a budget challenge by reducing cost, or solving a specific tactical challenge, but result in highly complex environments, that may be difficult to manage and maintain and limit the future potential of your business. Put differently, some solutions might push today's challenge into the future, resulting in a more complex and expensive solution. There is no such thing as a "1 size fits all" IT solution for business. If all companies implemented business solutions based upon technology that required, or forced the same business processes across all businesses in an industry, it would be extremely difficult to show competitive advantage through "unique business value". It would be equally difficult to "evolve" to meet or exceed business needs and keep up with today's rapid pace of change. How does one ensure that they do not jump from one trap directly into another? Or to put it positively, there are solutions available today that can address these challenges and issues. How does one ensure that the buying decision of today will serve the business well for years into the future? Intelligent & Informed decisions - "buying right" In a previous blog entry, we discussed the value of linking tactical to strategic The key is driving the focus to what is best for your business, handling today's tactical issues while also aligning with a roadmap/strategy that is tightly aligned with your strategic business objectives. When considering the plethora of possible options that provide various approaches to solving today's complex business problems, it is extremely important to ensure that vendors supplying those options, focus on what is best for your business, supplying sufficient information, providing adequate answers to questions, addressing challenges, issues, concerns and objections honestly and openly, and focus on supplying solutions that are tailored for, and deliver the most business value possible for your business. Here are a few questions to consider relative to the proposed options that should help ensure that today's solution doesn't become tomorrow's problem. Do the proposed solutions: Solve the problem(s) you are trying to address? Provide a solid foundation upon which to grow/enhance your business? Provide tactical gains that align with and enable your strategic business goals/objectives? Provide an infrastructure that can be leveraged with subsequent projects? Solve problems for the business overall, the lines of business, or just IT? Simplify your current environment Provide the basis for business: Efficiency Agility Clarity governance, risk, compliance real time business visibility and trend analysis Does your IT staff have the knowledge/experience to successfully manage the proposed systems once they are deployed in production? Done well, you will be presented with options tailored to your business, that enable you to drive the "unique business value" necessary to help your business stand out from others, creating a distinct competitive advantage, delivering what your customers need, when they need it, so you can attract new customers, new business, and grow top line revenue, all at a cost that provides a strong Return on Investment/Return on Assets. The net result is growth with managed cost providing significantly improved profit margin and shareholder value.

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• Enable remote VNC from the commandline?

  - by Stefan Lasiewski

  I have one computer running Ubuntu 10.04, and is running Vino, the default VNC server. I have a second Windows box which is running a VNC client, but does not have any X11 capabilities. I am ssh'd into the Ubuntu host from the Windows host, but I forgot to enable VNC access on the Ubuntu host. On the Ubuntu host, is there a way for me to enable VNC connections from the Ubuntu commandline? Update: As @koanhead says below, there is no man page for vino (e.g. man -k vino and info vino return nothing), and vino --help doesn't show any help).

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• Objective C style nil in java?

  - by Usman Ismail

  Objective C has a concept of a nil object which would accept any method call with any parameters without complaining and silently return another nil. I have used something similar in Java using easymock and mockito for testing. Is there something similar for main line code? Is it even a good idea to have something like this? One use-case where I am considering using it is with optional metrics. We have codahale metrics counters on which we call mark() every time an event is generated. This is surrounded by an If/then to check for metrics enabled flag. I could just use a nil object as counter and silently accept the mark call if metrics are not enabled.

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• TFS API-Process Template currently applied to the Team Project

  - by Tarun Arora

  Download Demo Solution - here In this blog post I’ll show you how to use the TFS API to get the name of the Process Template that is currently applied to the Team Project. You can also download the demo solution attached, I’ve tested this solution against TFS 2010 and TFS 2011.    1. Connecting to TFS Programmatically I have a blog post that shows you from where to download the VS 2010 SP1 SDK and how to connect to TFS programmatically. private TfsTeamProjectCollection _tfs; private string _selectedTeamProject;   TeamProjectPicker tfsPP = new TeamProjectPicker(TeamProjectPickerMode.SingleProject, false); tfsPP.ShowDialog(); this._tfs = tfsPP.SelectedTeamProjectCollection; this._selectedTeamProject = tfsPP.SelectedProjects[0].Name; 2. Programmatically get the Process Template details of the selected Team Project I’ll be making use of the VersionControlServer service to get the Team Project details and the ICommonStructureService to get the Project Properties. private ProjectProperty[] GetProcessTemplateDetailsForTheSelectedProject() { var vcs = _tfs.GetService<VersionControlServer>(); var ics = _tfs.GetService<ICommonStructureService>(); ProjectProperty[] ProjectProperties = null; var p = vcs.GetTeamProject(_selectedTeamProject); string ProjectName = string.Empty; string ProjectState = String.Empty; int templateId = 0; ProjectProperties = null; ics.GetProjectProperties(p.ArtifactUri.AbsoluteUri, out ProjectName, out ProjectState, out templateId, out ProjectProperties); return ProjectProperties; } 3. What’s the catch? The ProjectProperties will contain a property “Process Template” which as a value has the name of the process template. So, you will be able to use the below line of code to get the name of the process template. var processTemplateName = processTemplateDetails.Where(pt => pt.Name == "Process Template").Select(pt => pt.Value).FirstOrDefault();   However, if the process template does not contain the property “Process Template” then you will need to add it. So, the question becomes how do i add the Name property to the Process Template. Download the Process Template from the Process Template Manager on your local        Once you have downloaded the Process Template to your local machine, navigate to the Classification folder with in the template       From the classification folder open Classification.xml        Add a new property <property name=”Process Template” value=”MSF for CMMI Process Improvement v5.0” />           4. Putting it all together… using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using Microsoft.TeamFoundation.Client; using Microsoft.TeamFoundation.VersionControl.Client; using Microsoft.TeamFoundation.Server; using System.Diagnostics; using Microsoft.TeamFoundation.WorkItemTracking.Client; namespace TfsAPIDemoProcessTemplate { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private TfsTeamProjectCollection _tfs; private string _selectedTeamProject; private void btnConnect_Click(object sender, EventArgs e) { TeamProjectPicker tfsPP = new TeamProjectPicker(TeamProjectPickerMode.SingleProject, false); tfsPP.ShowDialog(); this._tfs = tfsPP.SelectedTeamProjectCollection; this._selectedTeamProject = tfsPP.SelectedProjects[0].Name; var processTemplateDetails = GetProcessTemplateDetailsForTheSelectedProject(); listBox1.Items.Clear(); listBox1.Items.Add(String.Format("Team Project Selected => '{0}'", _selectedTeamProject)); listBox1.Items.Add(Environment.NewLine); var processTemplateName = processTemplateDetails.Where(pt => pt.Name == "Process Template") .Select(pt => pt.Value).FirstOrDefault(); if (!string.IsNullOrEmpty(processTemplateName)) { listBox1.Items.Add(Environment.NewLine); listBox1.Items.Add(String.Format("Process Template Name: {0}", processTemplateName)); } else { listBox1.Items.Add(String.Format("The Process Template does not have the 'Name' property set up")); listBox1.Items.Add(String.Format("***TIP: Download the Process Template and in Classification.xml add a new property Name, update the template then you will be able to see the Process Template Name***")); listBox1.Items.Add(String.Format(" - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -")); } } private ProjectProperty[] GetProcessTemplateDetailsForTheSelectedProject() { var vcs = _tfs.GetService<VersionControlServer>(); var ics = _tfs.GetService<ICommonStructureService>(); ProjectProperty[] ProjectProperties = null; var p = vcs.GetTeamProject(_selectedTeamProject); string ProjectName = string.Empty; string ProjectState = String.Empty; int templateId = 0; ProjectProperties = null; ics.GetProjectProperties(p.ArtifactUri.AbsoluteUri, out ProjectName, out ProjectState, out templateId, out ProjectProperties); return ProjectProperties; } } } Thank you for taking the time out and reading this blog post. If you enjoyed the post, remember to subscribe to http://feeds.feedburner.com/TarunArora. Have you come across a better way of doing this, please share your experience here. Questions/Feedback/Suggestions, etc please leave a comment. Thank You! Share this post : CodeProject

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• Mixing Objective-C and C++: Game Loop Parts

  - by Peteyslatts

  I'm trying to write all of my game in C++ except for drawing and game loop timing. Those parts are going to be in Objective-C for iOS. Right now, I have ViewController handling the update cycle, but I want to create a GameModel class that ViewController could update. I want GameModel to be in C++. I know how to integrate these two classes. My problem is how to have these two parts interact with the drawing and image loading. GameModel will keep track of a list of children of type GameObject. These GameObjects update every frame, and then need to pass position and visibility data to whatever class or method will handle drawing. I feel like I'm answering my own question now (talking it out helps) but would it be a good idea to put all of the visible game objects into an array at the end of the update method, return it, and use that to update graphics inside ViewController?

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• Shallow Copy vs DeepCopy in C#.NET

  Hope below example helps to understand the difference. Please drop a comment if any doubts. using System; using System.IO; using System.Runtime.Serialization.Formatters.Binary; namespace ShallowCopyVsDeepCopy {     class Program     {         static void Main(string[] args)         {             var e1 = new Emp { EmpNo = 10, EmpName = "Smith", Department = new Dep { DeptNo = 100, DeptName = "Finance" } };             var e2 = e1.ShallowClone();             e1.Department.DeptName = "Accounts";             Console.WriteLine(e2.Department.DeptName);             var e3 = new Emp { EmpNo = 10, EmpName = "Smith", Department = new Dep { DeptNo = 100, DeptName = "Finance" } };             var e4 = e3.DeepClone();             e3.Department.DeptName = "Accounts";             Console.WriteLine(e4.Department.DeptName);         }     }     [Serializable]     class Dep     {         public int DeptNo { get; set; }         public String DeptName { get; set; }     }     [Serializable]     class Emp     {         public int EmpNo { get; set; }         public String EmpName { get; set; }         public Dep Department { get; set; }         public Emp ShallowClone()         {             return (Emp)this.MemberwiseClone();         }         public Emp DeepClone()         {             MemoryStream ms = new MemoryStream();             BinaryFormatter bf = new BinaryFormatter();             bf.Serialize(ms, this);             ms.Seek(0, SeekOrigin.Begin);             object copy = bf.Deserialize(ms);             ms.Close();             return copy as Emp;         }     } } span.fullpost {display:none;}

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• Hiding an item conditionally through SPEL in OAF ( VO Extension + Personalization )

  - by Manoj Madhusoodanan

  In this blog I will explain how to conditionally set property of an item through personalization.Let me discuss using a business scenario. My customer wants to make Hold from Payment/ All Invoices column readonly when the Operating Unit is UK ( Configured in a lookup XXCUST_EXCLUDED_ORGS ). Analysis First thing is we have to find out the page and business components. Page: /oracle/apps/pos/supplier/webui/QuickUpdatePGView Object: oracle.apps.pos.supplier.server.SitesVO Solution Download oracle.apps.pos.supplier.server.SitesVO from $JAVA_TOP to JDEV_USER_HOME/myprojects.Make sure the transfer mode of the file (See below table). Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} File Type Transfer Mode .xml ASCII .class Binary .tar Binary .java ASCII  Since there is no VO attribute available to determine the Site Org against the lookup Org we have to add the logic inside a custom VO attribute. So VO extension is required in this scenario. Add an attribute "isPymtReadOnlyStr" in the existing query.This column returns 'Y' if there is a match in the lookup otherwise 'N'. Create a transient attribute "isPymtReadOnly" of type BOOLEAN.This will return TRUE if "isPymtReadOnlyStr" is "Y" otherwise FALSE. The reason behind adding the "isPymtReadOnly" is we are setting the item property as readonly through SPEL.It will recognize only BOOLEAN.But SQL query doesn't support BOOLEAN.So we are building a BOOLEAN attribute from the SQL which will use in the personalization layer to set the item property. Steps 1) Create a new VO xxcust.oracle.apps.pos.supplier.server.XXCUSTSitesVO which extends from oracle.apps.pos.supplier.server.SitesVO. Make sure the binding style should be same as SitesVO. Create the XXCUSTSitesVO which same query of SitesVO.Later we will add the new attribute to XXCUSTSitesVO. At this point of time all the existing VO attributes are of Updatable property as "Always". Press Finish without creating XXCUSTSitesVORowImpl.java 2) Select the XXCUSTSitesVO from JDeveloper Application Navigator. Modify the query and add the extra column. 3) Create a new transient attribute as follows. 4) Once you modify the query all the existing attributes Updatable property will change to Never.So revert that property back to orginal. 5) Create XXCUSTSitesVORowImpl.java by checking the following check box. 6) Add the following code snippet in XXCUSTSitesVORowImpl.java 7) Create the substitution for SitesVO as follows. Following entry will get created in current jpx file.    <Substitutes>      <Substitute OldName ="oracle.apps.pos.supplier.server.SitesVO" NewName ="xxcust.oracle.apps.pos.supplier.server.XXCUSTSitesVO" />   </Substitutes> 8) Migrate XXCUSTSitesVOImpl.java,XXCUSTSitesVORowImpl.java and XXCUSTSitesVO.xml from desktop to actual instance. 9) Migrate the substitution using jpximporter. 10) Restart the server and verify the substitution has done perfectly. 11) Go to /oracle/apps/pos/supplier/webui/QuickUpdatePG and personalize the page.Set the item read only property to ${oa.SitesVO.IsPymtReadOnly} 12) Click on Apply and in next page click on Return to Application. Verify your output.  Note: You can remove the substitution using following script.Please click here.

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• Ahk script and C++ communication [closed]

  - by Tony

  I wish to use the fuctions of autohotkey within a C++ program. I am currently running my scripts triggered by the c++ program- I just run them as a .bat file. This works well but the problem is that I cannot return values from the script to the c++ program. I wish to be able to read the position of the mouse from the script and make decisions based upon this in my C++ program. My scripts do quite complex things- so doing this in autohotkey is the best solution for me- I have knowledge of C, but little of C++. I have read about the Autohotkey .DLL - I know how to trigger it but not how to read values from it. If anyone could instruct me or even post example code of a .dll being loaded and a value sent to a script and a value returned- I would be eternally grateful!! I have spent hours on this and to no avail!!

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• Howto install google-mock on Ubuntu 12.10

  - by user1459339

  I am having hard time trying to install Google C++ Mocking Framework. I have successfully run sudo apt-get install google-mock. Then I tried to compile this sample file #include "gmock/gmock.h" int main(int argc, char** argv) { ::testing::InitGoogleMock(&argc, argv); return RUN_ALL_TESTS(); } with g++ -lgmock main.cpp and these errors have shown main.cpp:(.text+0x1e): undefined reference to `testing::InitGoogleMock(int*, char**)' main.cpp:(.text+0x23): undefined reference to `testing::UnitTest::GetInstance()' main.cpp:(.text+0x2b): undefined reference to `testing::UnitTest::Run()' collect2: error: ld returned 1 exit status I guess the linker can not find the library files. Does anybody know how to fix this?

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• Watch the Silverlight 4 Launch event and LIVE QA with ScottGu and others

  Next week on 13-April at 8:00 AM PST Scott Guthrie will deliver a keynote address for the DevConnections conference being held in Las Vegas, NV. Scott will provide updates on the progress made in Silverlight 4 and will provide the details of availability of the developer tools, runtime and other news. Mark your calendars and return to the Silverlight community site to tune into the LIVE event. After the keynote, Channel 9 will be hosting interviews with Scott and other key members of the Silverlight...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• UserAppDataPath in WPF

  - by psheriff

  In Windows Forms applications you were able to get to your user's roaming profile directory very easily using the Application.UserAppDataPath property. This folder allows you to store information for your program in a custom folder specifically for your program. The format of this directory looks like this: C:\Users\YOUR NAME\AppData\Roaming\COMPANY NAME\APPLICATION NAME\APPLICATION VERSION For example, on my Windows 7 64-bit system, this folder would look like this for a Windows Forms Application: C:\Users\PSheriff\AppData\Roaming\PDSA, Inc.\WindowsFormsApplication1\1.0.0.0 For some reason Microsoft did not expose this property from the Application object of WPF applications. I guess they think that we don't need this property in WPF? Well, sometimes we still do need to get at this folder. You have two choices on how to retrieve this property. Add a reference to the System.Windows.Forms.dll to your WPF application and use this property directly. Or, you can write your own method to build the same path. If you add a reference to the System.Windows.Forms.dll you will need to use System.Windows.Forms.Application.UserAppDataPath to access this property. Create a GetUserAppDataPath Method in WPF If you want to build this path you can do so with just a few method calls in WPF using Reflection. The code below shows this fairly simple method to retrieve the same folder as shown above. C#using System.Reflection; public string GetUserAppDataPath(){  string path = string.Empty;  Assembly assm;  Type at;  object[] r;   // Get the .EXE assembly  assm = Assembly.GetEntryAssembly();  // Get a 'Type' of the AssemblyCompanyAttribute  at = typeof(AssemblyCompanyAttribute);  // Get a collection of custom attributes from the .EXE assembly  r = assm.GetCustomAttributes(at, false);  // Get the Company Attribute  AssemblyCompanyAttribute ct =                 ((AssemblyCompanyAttribute)(r[0]));  // Build the User App Data Path  path = Environment.GetFolderPath(              Environment.SpecialFolder.ApplicationData);  path += @"\" + ct.Company;  path += @"\" + assm.GetName().Version.ToString();   return path;} Visual BasicPublic Function GetUserAppDataPath() As String  Dim path As String = String.Empty  Dim assm As Assembly  Dim at As Type  Dim r As Object()   ' Get the .EXE assembly  assm = Assembly.GetEntryAssembly()  ' Get a 'Type' of the AssemblyCompanyAttribute  at = GetType(AssemblyCompanyAttribute)  ' Get a collection of custom attributes from the .EXE assembly  r = assm.GetCustomAttributes(at, False)  ' Get the Company Attribute  Dim ct As AssemblyCompanyAttribute = _                 DirectCast(r(0), AssemblyCompanyAttribute)  ' Build the User App Data Path  path = Environment.GetFolderPath( _                 Environment.SpecialFolder.ApplicationData)  path &= "\" & ct.Company  path &= "\" & assm.GetName().Version.ToString()   Return pathEnd Function Summary Getting the User Application Data Path folder in WPF is fairly simple with just a few method calls using Reflection. Of course, there is absolutely no reason you cannot just add a reference to the System.Windows.Forms.dll to your WPF application and use that Application object. After all, System.Windows.Forms.dll is a part of the .NET Framework and can be used from WPF with no issues at all. NOTE: Visit http://www.pdsa.com/downloads to get more tips and tricks like this one. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **We frequently offer a FREE gift for readers of my blog. Visit http://www.pdsa.com/Event/Blog for your FREE gift!

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• How to set a target as image [on hold]

  - by Zadalaxmi

  How to set a target as image in given code. public void addListenerForImage(final Image roomImage) { final DragAndDrop dragAndDrop = new DragAndDrop(); dragAndDrop.addSource(new DragAndDrop.Source(roomImage) { public DragAndDrop.Payload dragStart (InputEvent event, float x, float y, int pointer) { DragAndDrop.Payload payload = new DragAndDrop.Payload(); payload.setDragActor(roomImage); dragAndDrop.setDragActorPosition(-x, -y + roomImage.getHeight()); return payload; } public void dragStop (InputEvent event, float x, float y, int pointer,Target target) { roomImage.setBounds(50, 125, roomImage.getWidth(), roomImage.getHeight()); if(target != null) { roomImage.setPosition(target.getActor().getX(), target.getActor().getY()); } System.out.println(target); stage.addActor(roomImage); } }); My problem is i can drag the images and i am not able to set target as image; and target shows as null;One more if a invisible some of the images in group how can i test that it is overlapped or not;Please give some links and suggestion

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• Do Not Optimize Without Measuring

  - by Alois Kraus

  Recently I had to do some performance work which included reading a lot of code. It is fascinating with what ideas people come up to solve a problem. Especially when there is no problem. When you look at other peoples code you will not be able to tell if it is well performing or not by reading it. You need to execute it with some sort of tracing or even better under a profiler. The first rule of the performance club is not to think and then to optimize but to measure, think and then optimize. The second rule is to do this do this in a loop to prevent slipping in bad things for too long into your code base. If you skip for some reason the measure step and optimize directly it is like changing the wave function in quantum mechanics. This has no observable effect in our world since it does represent only a probability distribution of all possible values. In quantum mechanics you need to let the wave function collapse to a single value. A collapsed wave function has therefore not many but one distinct value. This is what we physicists call a measurement. If you optimize your application without measuring it you are just changing the probability distribution of your potential performance values. Which performance your application actually has is still unknown. You only know that it will be within a specific range with a certain probability. As usual there are unlikely values within your distribution like a startup time of 20 minutes which should only happen once in 100 000 years. 100 000 years are a very short time when the first customer tries your heavily distributed networking application to run over a slow WIFI network… What is the point of this? Every programmer/architect has a mental performance model in his head. A model has always a set of explicit preconditions and a lot more implicit assumptions baked into it. When the model is good it will help you to think of good designs but it can also be the source of problems. In real world systems not all assumptions of your performance model (implicit or explicit) hold true any longer. The only way to connect your performance model and the real world is to measure it. In the WIFI example the model did assume a low latency high bandwidth LAN connection. If this assumption becomes wrong the system did have a drastic change in startup time. Lets look at a example. Lets assume we want to cache some expensive UI resource like fonts objects. For this undertaking we do create a Cache class with the UI themes we want to support. Since Fonts are expensive objects we do create it on demand the first time the theme is requested. A simple example of a Theme cache might look like this: using System; using System.Collections.Generic; using System.Drawing; struct Theme { public Color Color; public Font Font; } static class ThemeCache { static Dictionary<string, Theme> _Cache = new Dictionary<string, Theme> { {"Default", new Theme { Color = Color.AliceBlue }}, {"Theme12", new Theme { Color = Color.Aqua }}, }; public static Theme Get(string theme) { Theme cached = _Cache[theme]; if (cached.Font == null) { Console.WriteLine("Creating new font"); cached.Font = new Font("Arial", 8); } return cached; } } class Program { static void Main(string[] args) { Theme item = ThemeCache.Get("Theme12"); item = ThemeCache.Get("Theme12"); } } This cache does create font objects only once since on first retrieve of the Theme object the font is added to the Theme object. When we let the application run it should print “Creating new font” only once. Right? Wrong! The vigilant readers have spotted the issue already. The creator of this cache class wanted to get maximum performance. So he decided that the Theme object should be a value type (struct) to not put too much pressure on the garbage collector. The code Theme cached = _Cache[theme]; if (cached.Font == null) { Console.WriteLine("Creating new font"); cached.Font = new Font("Arial", 8); } does work with a copy of the value stored in the dictionary. This means we do mutate a copy of the Theme object and return it to our caller. But the original Theme object in the dictionary will have always null for the Font field! The solution is to change the declaration of struct Theme to class Theme or to update the theme object in the dictionary. Our cache as it is currently is actually a non caching cache. The funny thing was that I found out with a profiler by looking at which objects where finalized. I found way too many font objects to be finalized. After a bit debugging I found the allocation source for Font objects was this cache. Since this cache was there for years it means that the cache was never needed since I found no perf issue due to the creation of font objects. the cache was never profiled if it did bring any performance gain. to make the cache beneficial it needs to be accessed much more often. That was the story of the non caching cache. Next time I will write something something about measuring.

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• Implementing an Interceptor Using NHibernate’s Built In Dynamic Proxy Generator

  - by Ricardo Peres

  NHibernate 3.2 came with an included proxy generator, which means there is no longer the need – or the possibility, for that matter – to choose Castle DynamicProxy, LinFu or Spring. This is actually a good thing, because it means one less assembly to deploy. Apparently, this generator was based, at least partially, on LinFu. As there are not many tutorials out there demonstrating it’s usage, here’s one, for demonstrating one of the most requested features: implementing INotifyPropertyChanged. This interceptor, of course, will still feature all of NHibernate’s functionalities that you are used to, such as lazy loading, and such. We will start by implementing an NHibernate interceptor, by inheriting from the base class NHibernate.EmptyInterceptor. This class does not do anything by itself, but it allows us to plug in behavior by overriding some of its methods, in this case, Instantiate: 1: public class NotifyPropertyChangedInterceptor : EmptyInterceptor 2: { 3: private ISession session = null; 4:  5: private static readonly ProxyFactory factory = new ProxyFactory(); 6:  7: public override void SetSession(ISession session) 8: { 9: this.session = session; 10: base.SetSession(session); 11: } 12:  13: public override Object Instantiate(String clazz, EntityMode entityMode, Object id) 14: { 15: Type entityType = Type.GetType(clazz); 16: IProxy proxy = factory.CreateProxy(entityType, new _NotifyPropertyChangedInterceptor(), typeof(INotifyPropertyChanged)) as IProxy; 17: 18: _NotifyPropertyChangedInterceptor interceptor = proxy.Interceptor as _NotifyPropertyChangedInterceptor; 19: interceptor.Proxy = this.session.SessionFactory.GetClassMetadata(entityType).Instantiate(id, entityMode); 20:  21: this.session.SessionFactory.GetClassMetadata(entityType).SetIdentifier(proxy, id, entityMode); 22:  23: return (proxy); 24: } 25: } Then we need a class that implements the NHibernate dynamic proxy behavior, let’s place it inside our interceptor, because it will only need to be used there: 1: class _NotifyPropertyChangedInterceptor : NHibernate.Proxy.DynamicProxy.IInterceptor 2: { 3: private PropertyChangedEventHandler changed = delegate { }; 4:  5: public Object Proxy 6: { 7: get; 8: set;} 9:  10: #region IInterceptor Members 11:  12: public Object Intercept(InvocationInfo info) 13: { 14: Boolean isSetter = info.TargetMethod.Name.StartsWith("set_") == true; 15: Object result = null; 16:  17: if (info.TargetMethod.Name == "add_PropertyChanged") 18: { 19: PropertyChangedEventHandler propertyChangedEventHandler = info.Arguments[0] as PropertyChangedEventHandler; 20: this.changed += propertyChangedEventHandler; 21: } 22: else if (info.TargetMethod.Name == "remove_PropertyChanged") 23: { 24: PropertyChangedEventHandler propertyChangedEventHandler = info.Arguments[0] as PropertyChangedEventHandler; 25: this.changed -= propertyChangedEventHandler; 26: } 27: else 28: { 29: result = info.TargetMethod.Invoke(this.Proxy, info.Arguments); 30: } 31:  32: if (isSetter == true) 33: { 34: String propertyName = info.TargetMethod.Name.Substring("set_".Length); 35: this.changed(this.Proxy, new PropertyChangedEventArgs(propertyName)); 36: } 37:  38: return (result); 39: } 40:  41: #endregion 42: } What this does for every interceptable method (those who are either virtual or from the INotifyPropertyChanged) is: For methods that came from the INotifyPropertyChanged interface, add_PropertyChanged and remove_PropertyChanged (yes, events are methods ), we add an implementation that adds or removes the event handlers to the delegate which we declared as changed; For all the others, we direct them to the place where they are actually implemented, which is the Proxy field; If the call is setting a property, it fires afterwards the PropertyChanged event. In order to use this, we need to add the interceptor to the Configuration before building the ISessionFactory: 1: using (ISessionFactory factory = cfg.SetInterceptor(new NotifyPropertyChangedInterceptor()).BuildSessionFactory()) 2: { 3: using (ISession session = factory.OpenSession()) 4: using (ITransaction tx = session.BeginTransaction()) 5: { 6: Customer customer = session.Get<Customer>(100); //some id 7: INotifyPropertyChanged inpc = customer as INotifyPropertyChanged; 8: inpc.PropertyChanged += delegate(Object sender, PropertyChangedEventArgs e) 9: { 10: //fired when a property changes 11: }; 12: customer.Address = "some other address"; //will raise PropertyChanged 13: customer.RecentOrders.ToList(); //will trigger the lazy loading 14: } 15: } Any problems, questions, do drop me a line!

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• RTS Voxel Engine using LWJGL - Textures glitching

  - by Dieter Hubau

  I'm currently working on an RTS game engine using voxels. I have implemented a basic chunk manager using an Octree of Octrees which contains my voxels (simple square blocks, as in Minecraft). I'm using a Voronoi-based terrain generation to get a simplistic yet relatively realistic heightmap. I have no problem showing a 256*256*256 grid of voxels with a decent framerate (250), because of frustum culling, face culling and only rendering visible blocks. For example, in a random voxel grid of 256*256*256 I generally only render 100k-120k faces, not counting frustum culling. Frustum culling is only called every 100ms, since calling it every frame seemed a bit overkill. Now I have reached the stage of texturing and I'm experiencing some problems: Some experienced people might already see the problem, but if we zoom in, you can see the glitches more clearly: All the seams between my blocks are glitching and kind of 'overlapping' or something. It's much more visible when you're moving around. I'm using a single, simple texture map to draw on my cubes, where each texture is 16*16 pixels big: I have added black edges around the textures to get a kind of cellshaded look, I think it's cool. The texture map has 256 textures of each 16*16 pixels, meaning the total size of my texture map is 256*256 pixels. The code to update the ChunkManager: public void update(ChunkManager chunkManager) { for (Octree<Cube> chunk : chunks) { if (chunk.getId() < 0) { // generate an id for the chunk to be able to call it later chunk.setId(glGenLists(1)); } glNewList(chunk.getId(), GL_COMPILE); glBegin(GL_QUADS); faces += renderChunk(chunk); glEnd(); glEndList(); } } Where my renderChunk method is: private int renderChunk(Octree<Cube> node) { // keep track of the number of visible faces in this chunk int faces = 0; if (!node.isEmpty()) { if (node.isLeaf()) { faces += renderItem(node); } List<Octree<Cube>> children = node.getChildren(); if (children != null && !children.isEmpty()) { for (Octree<Cube> child : children) { faces += renderChunk(child); } } return faces; } Where my renderItem method is the following: private int renderItem(Octree<Cube> node) { Cube cube = node.getItem(-1, -1, -1); int faces = 0; float x = node.getPosition().x; float y = node.getPosition().y; float z = node.getPosition().z; float size = cube.getSize(); Vector3f point1 = new Vector3f(-size + x, -size + y, size + z); Vector3f point2 = new Vector3f(-size + x, size + y, size + z); Vector3f point3 = new Vector3f(size + x, size + y, size + z); Vector3f point4 = new Vector3f(size + x, -size + y, size + z); Vector3f point5 = new Vector3f(-size + x, -size + y, -size + z); Vector3f point6 = new Vector3f(-size + x, size + y, -size + z); Vector3f point7 = new Vector3f(size + x, size + y, -size + z); Vector3f point8 = new Vector3f(size + x, -size + y, -size + z); TextureCoordinates tc = textureManager.getTextureCoordinates(cube.getCubeType()); // front face if (cube.isVisible(CubeSide.FRONT)) { faces++; glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point1.x, point1.y, point1.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point4.x, point4.y, point4.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point3.x, point3.y, point3.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point2.x, point2.y, point2.z); } // back face if (cube.isVisible(CubeSide.BACK)) { faces++; glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point5.x, point5.y, point5.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point6.x, point6.y, point6.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point7.x, point7.y, point7.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point8.x, point8.y, point8.z); } // left face if (cube.isVisible(CubeSide.SIDE_LEFT)) { faces++; glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point5.x, point5.y, point5.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v]); glVertex3f(point1.x, point1.y, point1.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u + 1], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point2.x, point2.y, point2.z); glTexCoord2f(TEXTURE_U_COORDINATES[tc.u], TEXTURE_V_COORDINATES[tc.v + 1]); glVertex3f(point6.x, point6.y, point6.z); } // ETC ETC return faces; } When all this is done, I simply render my lists every frame, like this: public void render(ChunkManager chunkManager) { glBindTexture(GL_TEXTURE_2D, textureManager.getCubeTextureId()); // load all chunks from the tree List<Octree<Cube>> chunks = chunkManager.getTree().getAllItems(); for (Octree<Cube> chunk : chunks) { if (frustum.cubeInFrustum(chunk.getPosition(), chunk.getSize() / 2)) { glCallList(chunk.getId()); } } } I don't know if anyone is willing to go through all of this code or maybe you can spot the problem right away, but that is basically the problem, and I can't find a solution :-) Thanks for reading and any help is appreciated!

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