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• How To: Automatically Remove www from a Domain in IIS7

  I recently moved the DevMavens.com site from one server to another and needed to ensure that the www.devmavens.com domain correctly redirected to simply devmavens.com.  This is important for SEO reasons (you dont want multiple domains to refer to the same content) and its generally better to use the shorter URL (www is so 20th century) rather than wasting 4 characters for zero gain. My friend and IIS guru Scott Forsyth pointed me to his blog post on how to set up IIS URL Rewriting.  To get started, you simply install IIS Rewrite from this link using the super awesome Web Platform Installer.  You should get something like this when youre done with the install: If you already have IIS Manager open, you may need to close it and re-open it before you see the URL Rewrite module.  Once you do, you should see it listed for any given Site under the IIS section: Double click on the URL Rewrite icon, and then choose the Add Rule(s) action.  You can simply create a blank rule, and name it Redirect from www to domain.com.  Essentially were following the instructions from Scott Forsyths post, but in reverse since hes showing how to add 4 useless characters to the URL and Im interested in removing them. After adding the name, well set the Match Url sections Using dropdown to Wildcards and specify a pattern of simply * to match anything. In the Conditions section we need to add a new condition with an Input of {HTTP_HOST} such that it should match the pattern www.devmavens.com (replace this with your domain). Ignore the Server Variables section. Set the action to Redirect and the Redirect URL to http://devmavens.com/{R:0} (replace with your domain).  The {R:0} will be replaced with whatever the user had entered.  So if they were going to http://www.devmavens.com/default.aspx theyll now be going to http://devmavens.com/default.aspx. The complete Inbound Rule should look like this: Thats it!  Test it out and make sure you havent accidentally used my exact URLs and started sending all of your users to devmavens.com! :)  Be sure to read Scotts post for more information on how to use regular expressions for your rules, and how to set them up via web.config rather than IIS manager. 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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• Translate jQuery UI Datepicker format to .Net Date format

  - by Michael Freidgeim

  I needed to use the same date format in client jQuery UI Datepicker and server ASP.NET code. The actual format can be different for different localization cultures.I decided to translate Datepicker format to .Net Date format similar as it was asked to do opposite operation in http://stackoverflow.com/questions/8531247/jquery-datepickers-dateformat-how-to-integrate-with-net-current-culture-date Note that replace command need to replace whole words and order of calls is importantFunction that does opposite operation (translate  .Net Date format toDatepicker format) is described in http://www.codeproject.com/Articles/62031/JQueryUI-Datepicker-in-ASP-NET-MVC /// <summary> /// Uses regex '\b' as suggested in //http://stackoverflow.com/questions/6143642/way-to-have-string-replace-only-hit-whole-words /// </summary> /// <param name="original"></param> /// <param name="wordToFind"></param> /// <param name="replacement"></param> /// <param name="regexOptions"></param> /// <returns></returns> static public string ReplaceWholeWord(this string original, string wordToFind, string replacement, RegexOptions regexOptions = RegexOptions.None) { string pattern = String.Format(@"\b{0}\b", wordToFind); string ret=Regex.Replace(original, pattern, replacement, regexOptions); return ret; } /// <summary> /// E.g "DD, d MM, yy" to ,"dddd, d MMMM, yyyy" /// </summary> /// <param name="datePickerFormat"></param> /// <returns></returns> /// <remarks> /// Idea to replace from http://stackoverflow.com/questions/8531247/jquery-datepickers-dateformat-how-to-integrate-with-net-current-culture-date ///From http://docs.jquery.com/UI/Datepicker/$.datepicker.formatDate to http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx ///Format a date into a string value with a specified format. ///d - day of month (no leading zero) ---.Net the same ///dd - day of month (two digit) ---.Net the same ///D - day name short ---.Net "ddd" ///DD - day name long ---.Net "dddd" ///m - month of year (no leading zero) ---.Net "M" ///mm - month of year (two digit) ---.Net "MM" ///M - month name short ---.Net "MMM" ///MM - month name long ---.Net "MMMM" ///y - year (two digit) ---.Net "yy" ///yy - year (four digit) ---.Net "yyyy" /// </remarks> public static string JQueryDatePickerFormatToDotNetDateFormat(string datePickerFormat) { string sRet = datePickerFormat.ReplaceWholeWord("DD", "dddd").ReplaceWholeWord("D", "ddd"); sRet = sRet.ReplaceWholeWord("M", "MMM").ReplaceWholeWord("MM", "MMMM").ReplaceWholeWord("m", "M").ReplaceWholeWord("mm", "MM");//order is important sRet = sRet.ReplaceWholeWord("yy", "yyyy").ReplaceWholeWord("y", "yy");//order is important return sRet; }

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• When should complexity be removed?

  - by ElGringoGrande

  Prematurely introducing complexity by implementing design patterns before they are needed is not good practice. But if you follow all (or even most of) the SOLID principles and use common design patterns you will introduce some complexity as features and requirements are added or changed to keep your design as maintainable and flexible as needed. However once that complexity is introduced and working like a champ when do you removed it? Example. I have an application written for a client. When originally created there where several ways to give raises to employees. I used the strategy pattern and factory to keep the whole process nice and clean. Over time certain raise methods where added or removed by the application owner. Time passes and new owner takes over. This new owner is hard nosed, keeps everything simple and only has one single way to give a raise. The complexity needed by the strategy pattern is no longer needed. If I where to code this from the requirements as they are now I would not introduce this extra complexity (but make sure I could introduce it with little or no work should the need arise). So do I remove the strategy implementation now? I don't think this new owner will ever change how raises are given. But the application itself has demonstrated that this could happen. Of course this is just one example in an application where a new owner takes over and has simplified many processes. I could remove dozens of classes, interfaces and factories and make the whole application much more simple. Note that the current implementation does works just fine and the owner is happy with it (and surprised and even happier that I was able to implement her changes so quickly because of the discussed complexity). I admit that a small part of this doubt is because it is highly likely the new owner isn't going to use me any longer. I don't really care that somebody else will take this over since it has not been a big income generator. But I do care about 2 (related) things I care a bit that the new maintainer will have to think a bit harder when trying to understand the code. Complexity is complexity and I don't want to anger the psycho maniac coming after me. But even more I worry about a competitor seeing this complexity and thinking I just implement design patterns to pad my hours on jobs. Then spreading this rumor to hurt my other business. (I have heard this mentioned.) So... In general should previously needed complexity be removed even though it works and there has been a historically demonstrated need for the complexity but you have no indication that it will be needed in the future? Even if the question above is generally answered "no" is it wise to remove this "un-needed" complexity if handing off the project to a competitor (or stranger)?

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• Static class vs Singleton class in C# [closed]

  - by Floradu88

  Possible Duplicate: What is the difference between all-static-methods and applying a singleton pattern? I need to make a decision for a project I'm working of whether to use static or singleton. After reading an article like this I am inclined to use singleton. What is better to use static class or singleton? Edit 1 : Client Server Desktop Application. Please provide code oriented solutions.

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• Managing 404 error pages with noindex and url rewrite

  - by ZenMaster

  Currently I use custom 404 error pages, having the following meta on them : <meta content="noindex" name="robots"> My guess is this way Google will remove deleted pages faster from the index, anyone has experienced a case where it does ? Also, is it better to have the url path rewritten to the actual error page, like the url pattern: http://{mysite}/{404_error_page} or is it best to keep the old deleted page's url when serving a 404 error ?

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• SQLAuthority News – I am Presenting 2 Sessions at TechEd India

  - by pinaldave

  TechED is the event which I am always excited about. It is one of the largest technology in India. Microsoft Tech Ed India 2011 is the premier technical education and networking event for tech professionals interested in learning, connecting and exploring a broad set of current and soon-to-be released Microsoft technologies, tools, platforms and services. I am going to speak at the TechED on two very interesting and advanced subjects. Venue: The LaLiT Ashok Kumara Krupa High Grounds Bangalore – 560001, Karnataka, India Sessions Date: March 25, 2011 Understanding SQL Server Behavioral Pattern – SQL Server Extended Events Date and Time: March 25, 2011 12:00 PM to 01:00 PM History repeats itself! SQL Server 2008 has introduced a very powerful, yet very minimal reoccurring feature called Extended Events. This advanced session will teach experienced administrators’ capabilities that were not possible before. From T-SQL error to CPU bottleneck, error login to deadlocks –Extended Event can detect it for you. Understanding the pattern of events can prevent future mistakes. SQL Server Waits and Queues – Your Gateway to Perf. Troubleshooting Date and Time: March 25, 2011 04:15 PM to 05:15 PM Just like a horoscope, SQL Server Waits and Queues can reveal your past, explain your present and predict your future. SQL Server Performance Tuning uses the Waits and Queues as a proven method to identify the best opportunities to improve performance. A glance at Wait Types can tell where there is a bottleneck. Learn how to identify bottlenecks and potential resolutions in this fast paced, advanced performance tuning session. My session will be on the third day of the event and I am very sure that everybody will be in groove to learn new interesting subjects. I will have few give-away during and at the end of the session. I will not tell you what I will have but it will be for sure something you will love to have. Please make a point and reserve above time slots to attend my session. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology Tagged: SQL Extended Events

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• How to wire finite state machine into component-based architecture?

  - by Pup

  State machines seem to cause harmful dependencies in component-based architectures. How, specifically, is communication handled between a state machine and the components that carry out state-related behavior? Where I'm at: I'm new to component-based architectures. I'm making a fighting game, although I don't think that should matter. I envision my state machine being used to toggle states like "crouching", "dashing", "blocking", etc. I've found this state-management technique to be the most natural system for a component-based architecture, but it conflicts with techniques I've read about: Dynamic Game Object Component System for Mutable Behavior Characters It suggests that all components activate/deactivate themselves by continually checking a condition for activation. I think that actions like "running" or "walking" make sense as states, which is in disagreement with the accepted response here: finite state machine used in mario like platform game I've found this useful, but ambiguous: How to implement behavior in a component-based game architecture? It suggests having a separate component that contains nothing but a state machine. But, this necessitates some kind of coupling between the state machine component and nearly all the other components. I don't understand how this coupling should be handled. These are some guesses: A. Components depend on state machine: Components receive reference to state machine component's getState(), which returns an enumeration constant. Components update themselves regularly and check this as needed. B. State machine depends on components: The state machine component receives references to all the components it's monitoring. It queries their getState() methods to see where they're at. C. Some abstraction between them Use an event hub? Command pattern? D. Separate state objects that reference components State Pattern is used. Separate state objects are created, which activate/deactivate a set of components. State machine switches between state objects. I'm looking at components as implementations of aspects. They do everything that's needed internally to make that aspect happen. It seems like components should function on their own, without relying on other components. I know some dependencies are necessary, but state machines seem to want to control all of my components.

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• PASS Call for Speakers

  - by Paul Nielsen

  It's that time again - the PASS Summit 2010 (Seattle Nov 8-11) Call for Speakers is now open and accepting abstracts until June 5 th . personally, I'm on a pattern that on odd years I present what I'm excited about, and on even years I try try to proesent what I expect other are jazzed about, which takes a bit more work. Last year I offered to Coach any Pass Speakers for free and some success. I’m offering that service again startign with your abstracts. If you’d like me to review your abstracts...(read more)

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• Algorithm for spreading labels in a visually appealing and intuitive way

  - by mac

  Short version Is there a design pattern for distributing vehicle labels in a non-overlapping fashion, placing them as close as possible to the vehicle they refer to? If not, is any of the method I suggest viable? How would you implement this yourself? Extended version In the game I'm writing I have a bird-eye vision of my airborne vehicles. I also have next to each of the vehicles a small label with key-data about the vehicle. This is an actual screenshot: Now, since the vehicles could be flying at different altitudes, their icons could overlap. However I would like to never have their labels overlapping (or a label from vehicle 'A' overlap the icon of vehicle 'B'). Currently, I can detect collisions between sprites and I simply push away the offending label in a direction opposite to the otherwise-overlapped sprite. This works in most situations, but when the airspace get crowded, the label can get pushed very far away from its vehicle, even if there was an alternate "smarter" alternative. For example I get: B - label A -----------label C - label where it would be better (= label closer to the vehicle) to get: B - label label - A C - label EDIT: It also has to be considered that beside the overlapping vehicles case, there might be other configurations in which vehicles'labels could overlap (the ASCII-art examples show for example three very close vehicles in which the label of A would overlap the icon of B and C). I have two ideas on how to improve the present situation, but before spending time implementing them, I thought to turn to the community for advice (after all it seems like a "common enough problem" that a design pattern for it could exist). For what it's worth, here's the two ideas I was thinking to: Slot-isation of label space In this scenario I would divide all the screen into "slots" for the labels. Then, each vehicle would always have its label placed in the closest empty one (empty = no other sprites at that location. Spiralling search From the location of the vehicle on the screen, I would try to place the label at increasing angles and then at increasing radiuses, until a non-overlapping location is found. Something down the line of: try 0°, 10px try 10°, 10px try 20°, 10px ... try 350°, 10px try 0°, 20px try 10°, 20px ...

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• B2B - OSB Action Series

  - by Ramesh Nittur

  What are we planning 1. Why there is a synergy between OSB B2B integration. 2. Integrating OSB - B2B for a healthcare scenario 3. Various Integration pattern for OSB - B2B integration 4. Correlation of messages from OSB perspective 5. Correlation of messges from B2B perspective. 6. User experience in B2B, user experience in OSB.

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• Redirect/rewrite dynamic URL to sub-domain and create DNS for subdomain

  - by Abdul Majeed

  I have created an application in PHP, I would like to re-direct the following URL to corresponding sub-domain. Dynamic URL pattern: http://mydomain.com/mypage.php?user_name=testuser I wish to re-direct this to the corresponding sub domain: http://testuser.mydomain.com/ How do I create a rewrite rule for this purpose? How do I register DNS for sub-domain without using CPANEL? (I want to activate sub-domain when the user registers to the system.)

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• DI Patterns: Constructor Injection

  In this article, an excerpt from the book "Dependency Injection in .NET", we will take a detailed look at the DI pattern known as Constructor Injection.

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• Suddenly I have started getting 404 wordpress errors

  - by rikki

  Suddenly I have started getting 404 error on Google Webmaster. The backend is wordpress. 404 link is http://digitalanalog.in/2011/07/05/augmented-reality-interior-designer-kinect-hack/1345295070000/1345781600000 and it is pointing from this page http://digitalanalog.in/2011/07/05/augmented-reality-interior-designer-kinect-hack/1345295070000/ (this url has been automatically generated. Have no clue how this url exist) I am getting 404 errors of the similar pattern on all the pages

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• Where and how to reference composite MVP components?

  - by Lea Hayes

  I am learning about the MVP (Model-View-Presenter) Passive View flavour of MVC. I intend to expose events from view interfaces rather than using the observer pattern to remove explicit coupling with presenter. Context: Windows Forms / Client-Side JavaScript. I am led to believe that the MVP (or indeed MVC in general) pattern can be applied at various levels of a user interface ranging from the main "Window" to an embedded "Text Field". For instance, the model to the text field is probably just a string whereas the model to the "Window" contains application specific view state (like a persons name which resides within the contained text field). Given a more complex scenario: Documentation viewer which contains: TOC navigation pane Document view Search pane Since each of these 4 user interface items are complex and can be reused elsewhere it makes sense to design these using MVP. Given that each of these user interface items comprises of 3 components; which component should be nested? where? who instantiates them? Idea #1 - Embed View inside View from Parent View public class DocumentationViewer : Form, IDocumentationViewerView { public DocumentationViewer() { ... // Unclear as to how model and presenter are injected... TocPane = new TocPaneView(); } protected ITocPaneView TocPane { get; private set; } } Idea #2 - Embed Presenter inside View from Parent View public class DocumentationViewer : Form, IDocumentationViewerView { public DocumentationViewer() { ... // This doesn't seem like view logic... var tocPaneModel = new TocPaneModel(); var tocPaneView = new TocPaneView(); TocPane = new TocPanePresenter(tocPaneModel, tocPaneView); } protected TocPanePresenter TocPane { get; private set; } } Idea #3 - Embed View inside View from Parent Presenter public class DocumentationViewer : Form, IDocumentationViewerView { ... // Part of IDocumentationViewerView: public ITocPaneView TocPane { get; set; } } public class DocumentationViewerPresenter { public DocumentationViewerPresenter(DocumentationViewerModel model, IDocumentationViewerView view) { ... var tocPaneView = new TocPaneView(); var tocPaneModel = new TocPaneModel(model.Toc); var tocPanePresenter = new TocPanePresenter(tocPaneModel, tocPaneView); view.TocPane = tocPaneView; } } Some better idea...

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• Premature-Optimization and Performance Anxiety

  - by James Michael Hare

  While writing my post analyzing the new .NET 4 ConcurrentDictionary class (here), I fell into one of the classic blunders that I myself always love to warn about.  After analyzing the differences of time between a Dictionary with locking versus the new ConcurrentDictionary class, I noted that the ConcurrentDictionary was faster with read-heavy multi-threaded operations.  Then, I made the classic blunder of thinking that because the original Dictionary with locking was faster for those write-heavy uses, it was the best choice for those types of tasks.  In short, I fell into the premature-optimization anti-pattern. Basically, the premature-optimization anti-pattern is when a developer is coding very early for a perceived (whether rightly-or-wrongly) performance gain and sacrificing good design and maintainability in the process.  At best, the performance gains are usually negligible and at worst, can either negatively impact performance, or can degrade maintainability so much that time to market suffers or the code becomes very fragile due to the complexity. Keep in mind the distinction above.  I'm not talking about valid performance decisions.  There are decisions one should make when designing and writing an application that are valid performance decisions.  Examples of this are knowing the best data structures for a given situation (Dictionary versus List, for example) and choosing performance algorithms (linear search vs. binary search).  But these in my mind are macro optimizations.  The error is not in deciding to use a better data structure or algorithm, the anti-pattern as stated above is when you attempt to over-optimize early on in such a way that it sacrifices maintainability. In my case, I was actually considering trading the safety and maintainability gains of the ConcurrentDictionary (no locking required) for a slight performance gain by using the Dictionary with locking.  This would have been a mistake as I would be trading maintainability (ConcurrentDictionary requires no locking which helps readability) and safety (ConcurrentDictionary is safe for iteration even while being modified and you don't risk the developer locking incorrectly) -- and I fell for it even when I knew to watch out for it.  I think in my case, and it may be true for others as well, a large part of it was due to the time I was trained as a developer.  I began college in in the 90s when C and C++ was king and hardware speed and memory were still relatively priceless commodities and not to be squandered.  In those days, using a long instead of a short could waste precious resources, and as such, we were taught to try to minimize space and favor performance.  This is why in many cases such early code-bases were very hard to maintain.  I don't know how many times I heard back then to avoid too many function calls because of the overhead -- and in fact just last year I heard a new hire in the company where I work declare that she didn't want to refactor a long method because of function call overhead.  Now back then, that may have been a valid concern, but with today's modern hardware even if you're calling a trivial method in an extremely tight loop (which chances are the JIT compiler would optimize anyway) the results of removing method calls to speed up performance are negligible for the great majority of applications.  Now, obviously, there are those coding applications where speed is absolutely king (for example drivers, computer games, operating systems) where such sacrifices may be made.  But I would strongly advice against such optimization because of it's cost.  Many folks that are performing an optimization think it's always a win-win.  That they're simply adding speed to the application, what could possibly be wrong with that?  What they don't realize is the cost of their choice.  For every piece of straight-forward code that you obfuscate with performance enhancements, you risk the introduction of bugs in the long term technical debt of the application.  It will become so fragile over time that maintenance will become a nightmare.  I've seen such applications in places I have worked.  There are times I've seen applications where the designer was so obsessed with performance that they even designed their own memory management system for their application to try to squeeze out every ounce of performance.  Unfortunately, the application stability often suffers as a result and it is very difficult for anyone other than the original designer to maintain. I've even seen this recently where I heard a C++ developer bemoaning that in VS2010 the iterators are about twice as slow as they used to be because Microsoft added range checking (probably as part of the 0x standard implementation).  To me this was almost a joke.  Twice as slow sounds bad, but it almost never as bad as you think -- especially if you're gaining safety.  The only time twice is really that much slower is when once was too slow to begin with.  Think about it.  2 minutes is slow as a response time because 1 minute is slow.  But if an iterator takes 1 microsecond to move one position and a new, safer iterator takes 2 microseconds, this is trivial!  The only way you'd ever really notice this would be in iterating a collection just for the sake of iterating (i.e. no other operations).  To my mind, the added safety makes the extra time worth it. Always favor safety and maintainability when you can.  I know it can be a hard habit to break, especially if you started out your career early or in a language such as C where they are very performance conscious.  But in reality, these type of micro-optimizations only end up hurting you in the long run. Remember the two laws of optimization.  I'm not sure where I first heard these, but they are so true: For beginners: Do not optimize. For experts: Do not optimize yet. This is so true.  If you're a beginner, resist the urge to optimize at all costs.  And if you are an expert, delay that decision.  As long as you have chosen the right data structures and algorithms for your task, your performance will probably be more than sufficient.  Chances are it will be network, database, or disk hits that will be your slow-down, not your code.  As they say, 98% of your code's bottleneck is in 2% of your code so premature-optimization may add maintenance and safety debt that won't have any measurable impact.  Instead, code for maintainability and safety, and then, and only then, when you find a true bottleneck, then you should go back and optimize further.

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• const vs. readonly for a singleton

  - by GlenH7

  First off, I understand there are folk who oppose the use of singletons. I think it's an appropriate use in this case as it's constant state information, but I'm open to differing opinions / solutions. (See The singleton pattern and When should the singleton pattern not be used?) Second, for a broader audience: C++/CLI has a similar keyword to readonly with initonly, so this isn't strictly a C# type question. (Literal field versus constant variable in C++/CLI) Sidenote: A discussion of some of the nuances on using const or readonly. My Question: I have a singleton that anchors together some different data structures. Part of what I expose through that singleton are some lists and other objects, which represent the necessary keys or columns in order to connect the linked data structures. I doubt that anyone would try to change these objects through a different module, but I want to explicitly protect them from that risk. So I'm currently using a "readonly" modifier on those objects*. I'm using readonly instead of const with the lists as I read that using const will embed those items in the referencing assemblies and will therefore trigger a rebuild of those referencing assemblies if / when the list(s) is/are modified. This seems like a tighter coupling than I would want between the modules, but I wonder if I'm obsessing over a moot point. (This is question #2 below) The alternative I see to using "readonly" is to make the variables private and then wrap them with a public get. I'm struggling to see the advantage of this approach as it seems like wrapper code that doesn't provide much additional benefit. (This is question #1 below) It's highly unlikely that we'll change the contents or format of the lists - they're a compilation of things to avoid using magic strings all over the place. Unfortunately, not all the code has converted over to using this singleton's presentation of those strings. Likewise, I don't know that we'd change the containers / classes for the lists. So while I normally argue for the encapsulations advantages a get wrapper provides, I'm just not feeling it in this case. A representative sample of my singleton public sealed class mySingl { private static volatile mySingl sngl; private static object lockObject = new Object(); public readonly Dictionary<string, string> myDict = new Dictionary<string, string>() { {"I", "index"}, {"D", "display"}, }; public enum parms { ABC = 10, DEF = 20, FGH = 30 }; public readonly List<parms> specParms = new List<parms>() { parms.ABC, parms.FGH }; public static mySingl Instance { get { if(sngl == null) { lock(lockObject) { if(sngl == null) sngl = new mySingl(); } } return sngl; } } private mySingl() { doSomething(); } } Questions: Am I taking the most reasonable approach in this case? Should I be worrying about const vs. readonly? is there a better way of providing this information?

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• What strategy to use when starting in a new project with no documentation?

  - by Amir Rezaei

  Which is the best why to go when there are no documentation? For example how do you learn business rules? I have done the following steps: Since we are using a ORM tool I have printed a copy of database schema where I can see relations between objects. I have made a list of short names/table names that I will get explained. The project is client/server enterprise application using MVVM pattern.

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• Silverlight MVVM File Manager

  An implementation of the MVVM pattern to create a simple Silverlight 4 File Manager...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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• Naming Convention for Dedicated Thread Locking objects

  - by Chris Sinclair

  A relatively minor question, but I haven't been able to find official documentation or even blog opinion/discussions on it. Simply put: when I have a private object whose sole purpose is to serve for private lock, what do I name that object? class MyClass { private object LockingObject = new object(); void DoSomething() { lock(LockingObject) { //do something } } } What should we name LockingObject here? Also consider not just the name of the variable but how it looks in-code when locking. I've seen various examples, but seemingly no solid go-to advice: Plenty of usages of SyncRoot (and variations such as _syncRoot). Code Sample: lock(SyncRoot), lock(_syncRoot) This appears to be influenced by VB's equivalent SyncLock statement, the SyncRoot property that exists on some of the ICollection classes and part of some kind of SyncRoot design pattern (which arguably is a bad idea) Being in a C# context, not sure if I'd want to have a VBish naming. Even worse, in VB naming the variable the same as the keyword. Not sure if this would be a source of confusion or not. thisLock and lockThis from the MSDN articles: C# lock Statement, VB SyncLock Statement Code Sample: lock(thisLock), lock(lockThis) Not sure if these were named minimally purely for the example or not Kind of weird if we're using this within a static class/method. Several usages of PadLock (of varying casing) Code Sample: lock(PadLock), lock(padlock) Not bad, but my only beef is it unsurprisingly invokes the image of a physical "padlock" which I tend to not associate with the abstract threading concept. Naming the lock based on what it's intending to lock Code Sample: lock(messagesLock), lock(DictionaryLock), lock(commandQueueLock) In the VB SyncRoot MSDN page example, it has a simpleMessageList example with a private messagesLock object I don't think it's a good idea to name the lock against the type you're locking around ("DictionaryLock") as that's an implementation detail that may change. I prefer naming around the concept/object you're locking ("messagesLock" or "commandQueueLock") Interestingly, I very rarely see this naming convention for locking objects in code samples online or on StackOverflow. Question: What's your opinion generally about naming private locking objects? Recently, I've started naming them ThreadLock (so kinda like option 3), but I'm finding myself questioning that name. I'm frequently using this locking pattern (in the code sample provided above) throughout my applications so I thought it might make sense to get a more professional opinion/discussion about a solid naming convention for them. Thanks!

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• How accurate is "Business logic should be in a service, not in a model"?

  - by Jeroen Vannevel

  Situation Earlier this evening I gave an answer to a question on StackOverflow. The question: Editing of an existing object should be done in repository layer or in service? For example if I have a User that has debt. I want to change his debt. Should I do it in UserRepository or in service for example BuyingService by getting an object, editing it and saving it ? My answer: You should leave the responsibility of mutating an object to that same object and use the repository to retrieve this object. Example situation: class User { private int debt; // debt in cents private string name; // getters public void makePayment(int cents){ debt -= cents; } } class UserRepository { public User GetUserByName(string name){ // Get appropriate user from database } } A comment I received: Business logic should really be in a service. Not in a model. What does the internet say? So, this got me searching since I've never really (consciously) used a service layer. I started reading up on the Service Layer pattern and the Unit Of Work pattern but so far I can't say I'm convinced a service layer has to be used. Take for example this article by Martin Fowler on the anti-pattern of an Anemic Domain Model: There are objects, many named after the nouns in the domain space, and these objects are connected with the rich relationships and structure that true domain models have. The catch comes when you look at the behavior, and you realize that there is hardly any behavior on these objects, making them little more than bags of getters and setters. Indeed often these models come with design rules that say that you are not to put any domain logic in the the domain objects. Instead there are a set of service objects which capture all the domain logic. These services live on top of the domain model and use the domain model for data. (...) The logic that should be in a domain object is domain logic - validations, calculations, business rules - whatever you like to call it. To me, this seemed exactly what the situation was about: I advocated the manipulation of an object's data by introducing methods inside that class that do just that. However I realize that this should be a given either way, and it probably has more to do with how these methods are invoked (using a repository). I also had the feeling that in that article (see below), a Service Layer is more considered as a façade that delegates work to the underlying model, than an actual work-intensive layer. Application Layer [his name for Service Layer]: Defines the jobs the software is supposed to do and directs the expressive domain objects to work out problems. The tasks this layer is responsible for are meaningful to the business or necessary for interaction with the application layers of other systems. This layer is kept thin. It does not contain business rules or knowledge, but only coordinates tasks and delegates work to collaborations of domain objects in the next layer down. It does not have state reflecting the business situation, but it can have state that reflects the progress of a task for the user or the program. Which is reinforced here: Service interfaces. Services expose a service interface to which all inbound messages are sent. You can think of a service interface as a façade that exposes the business logic implemented in the application (typically, logic in the business layer) to potential consumers. And here: The service layer should be devoid of any application or business logic and should focus primarily on a few concerns. It should wrap Business Layer calls, translate your Domain in a common language that your clients can understand, and handle the communication medium between server and requesting client. This is a serious contrast to other resources that talk about the Service Layer: The service layer should consist of classes with methods that are units of work with actions that belong in the same transaction. Or the second answer to a question I've already linked: At some point, your application will want some business logic. Also, you might want to validate the input to make sure that there isn't something evil or nonperforming being requested. This logic belongs in your service layer. "Solution"? Following the guidelines in this answer, I came up with the following approach that uses a Service Layer: class UserController : Controller { private UserService _userService; public UserController(UserService userService){ _userService = userService; } public ActionResult MakeHimPay(string username, int amount) { _userService.MakeHimPay(username, amount); return RedirectToAction("ShowUserOverview"); } public ActionResult ShowUserOverview() { return View(); } } class UserService { private IUserRepository _userRepository; public UserService(IUserRepository userRepository) { _userRepository = userRepository; } public void MakeHimPay(username, amount) { _userRepository.GetUserByName(username).makePayment(amount); } } class UserRepository { public User GetUserByName(string name){ // Get appropriate user from database } } class User { private int debt; // debt in cents private string name; // getters public void makePayment(int cents){ debt -= cents; } } Conclusion All together not much has changed here: code from the controller has moved to the service layer (which is a good thing, so there is an upside to this approach). However this doesn't look like it had anything to do with my original answer. I realize design patterns are guidelines, not rules set in stone to be implemented whenever possible. Yet I have not found a definitive explanation of the service layer and how it should be regarded. Is it a means to simply extract logic from the controller and put it inside a service instead? Is it supposed to form a contract between the controller and the domain? Should there be a layer between the domain and the service layer? And, last but not least: following the original comment Business logic should really be in a service. Not in a model. Is this correct? How would I introduce my business logic in a service instead of the model?

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• In defense of SELECT * in production code, in some limited cases?

  - by Alexander Kuznetsov

  It is well known that SELECT * is not acceptable in production code, with the exception of this pattern: IF EXISTS( SELECT * We all know that whenever we see code code like this: Listing 1. "Bad" SQL SELECT Column1 , Column2 FROM ( SELECT c. * , ROW_NUMBER () OVER ( PARTITION BY Column1 ORDER BY Column2 ) AS rn FROM data.SomeTable AS c ) AS c WHERE rn < 5 we are supposed to automatically replace * with an explicit list of columns, as follows: Listing 2. "Good" SQL SELECT Column1 , Column2 FROM...(read more)

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• What are the software design essentials? [closed]

  - by Craig Schwarze

  I've decided to create a 1 page "cheat sheet" of essential software design principles for my programmers. It doesn't explain the principles in any great depth, but is simply there as a reference and a reminder. Here's what I've come up with - I would welcome your comments. What have I left out? What have I explained poorly? What is there that shouldn't be? Basic Design Principles The Principle of Least Surprise – your solution should be obvious, predictable and consistent. Keep It Simple Stupid (KISS) - the simplest solution is usually the best one. You Ain’t Gonna Need It (YAGNI) - create a solution for the current problem rather than what might happen in the future. Don’t Repeat Yourself (DRY) - rigorously remove duplication from your design and code. Advanced Design Principles Program to an interface, not an implementation – Don’t declare variables to be of a particular concrete class. Rather, declare them to an interface, and instantiate them using a creational pattern. Favour composition over inheritance – Don’t overuse inheritance. In most cases, rich behaviour is best added by instantiating objects, rather than inheriting from classes. Strive for loosely coupled designs – Minimise the interdependencies between objects. They should be able to interact with minimal knowledge of each other via small, tightly defined interfaces. Principle of Least Knowledge – Also called the “Law of Demeter”, and is colloquially summarised as “Only talk to your friends”. Specifically, a method in an object should only invoke methods on the object itself, objects passed as a parameter to the method, any object the method creates, any components of the object. SOLID Design Principles Single Responsibility Principle – Each class should have one well defined purpose, and only one reason to change. This reduces the fragility of your code, and makes it much more maintainable. Open/Close Principle – A class should be open to extension, but closed to modification. In practice, this means extracting the code that is most likely to change to another class, and then injecting it as required via an appropriate pattern. Liskov Substitution Principle – Subtypes must be substitutable for their base types. Essentially, get your inheritance right. In the classic example, type square should not inherit from type rectangle, as they have different properties (you can independently set the sides of a rectangle). Instead, both should inherit from type shape. Interface Segregation Principle – Clients should not be forced to depend upon methods they do not use. Don’t have fat interfaces, rather split them up into smaller, behaviour centric interfaces. Dependency Inversion Principle – There are two parts to this principle: High-level modules should not depend on low-level modules. Both should depend on abstractions. Abstractions should not depend on details. Details should depend on abstractions. In modern development, this is often handled by an IoC (Inversion of Control) container.

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• Design patterns to avoiding breaking the SRP while performing heavy data logging

  - by Kazark

  A class that performs both computations and data logging seems to have at least two responsibilities. Given a system for which the specifications require heavy data logging, what kind of design patterns or architectural patterns can be used to avoid bloating all the classes with logging calls every time they compute something? The decorator pattern be used (e.g. Interpolator decorated to LoggingInterpolator), but it seems that would result in a situation hardly more desirable in which almost every major class would need to be decorated with logging.

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• The worst anti-patterns you have came across.

  - by ?????????

  What are the worst anti-patterns you have came across in your career as a programmer? I'm mostly involved in java, although it is probably language-independent. I think the worst of it is what I call the main anti-pattern. It means program consisting of single, extremely big class (sometimes accompanied with a pair of little classes) which contains all logic. Typically with a big loop in which all business logic is contained, sometimes having tens of thousands of lines of code.

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• Bay Area Coherence Special Interest Group Next Meeting July 21, 2011

  - by csoto

  Date: Thursday, July 21, 2011 Time: 4:30pm - 8:15pm ET (note that Parking at 475 Sansome Closes at 8:30pm) Where: Oracle Office, 475 Sansome Street, San Francisco, CA Google Map We will be providing snacks and beverages. Register! - Registration is required for building security. Presentation Line Up:? 5:10pm - Batch Processing Using Coherence in Oracle Group Policy Administration - Paul Cleary, Oracle Oracle Insurance Policy Administration (OIPA) is a flexible, rules-based policy administration solution that provides full record keeping for all policy lifecycle transactions. One component of OIPA is Cycle processing, which is the batch processing of pending insurance transactions. This presentation introduces OIPA and Cycle processing, describing the unique challenges of processing a high volume of transactions within strict time windows. It then reviews how OIPA uses Oracle Coherence and the Processing Pattern to meet these challenges, describing implementation specifics that highlight the simplicity and robustness of the Processing Pattern. 6:10pm - Secure, Optimize, and Load Balance Coherence with F5 - Chris Akker, F5 F5 Networks, Inc., the global leader in Application Delivery Networking, helps the world’s largest enterprises and service providers realize the full value of virtualization, cloud computing, and on-demand IT. Recently, F5 and Oracle partnered to deliver a novel solution that integrates Oracle Coherence 3.7 with F5 BIG-IP Local Traffic Manager (LTM). This session will introduce F5 and how you can leverage BIG-IP LTM to secure, optimize, and load balance application traffic generated from Coherence*Extend clients across any number of servers in a cluster and to hardware-accelerate CPU-intensive SSL encryption. 7:10pm - Using Oracle Coherence to Enable Database Partitioning and DC Level Fault Tolerance - Alexei Ragozin, Independent Consultant and Brian Oliver, Oracle Partitioning is a very powerful technique for scaling database centric applications. One tricky part of partitioned architecture is routing of requests to the right database. The routing layer (routing table) should know the right database instance for each attribute which may be used for routing (e.g. account id, login, email, etc): it should be fast, it should fault tolerant and it should scale. All the above makes Oracle Coherence a natural choice for implementing such routing tables in partitioned architectures. This presentation will cover synchronization of the grid with multiple databases, conflict resolution, cross cluster replication and other aspects related to implementing robust partitioned architecture. Additional Info:?? - Download Past Presentations: The presentations from the previous meetings of the BACSIG are available for download here. Click on the presentation titles to download the PDF files. - Join the Coherence online community on our Oracle Coherence Users Group on LinkedIn. - Contact BACSIG with any comments, questions, presentation proposals and content suggestions.

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