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  • Acr.ExtDirect &ndash; Part 1 &ndash; Method Resolvers

    - by Allan Ritchie
    One of the most important things of any open source libraries in my opinion is to be as open as possible while avoiding having your library become invasive to your code/business model design.  I personally could never stand marking my business and/or data access code with attributes everywhere.  XML also isn’t really a fav with too many people these days since it comes with a startup performance hit and requires runtime compiling.  I find that there is a whole ton of communication libraries out there currently requiring this (ie. WCF, RIA, etc).  Even though Acr.ExtDirect comes with its own set of attributes, you can piggy-back the [ServiceContract] & [OperationContract] attributes from WCF if you choose.  It goes beyond that though, there are 2 others “out-of-the-box” implementations – Convention based & XML Configuration.    Convention – I don’t actually recommend using this one since it opens up all of your public instance methods to remote execution calls. XML Configuration – This isn’t so bad but requires you enter all of your methods and there operation types into the Castle XML configuration & as I said earlier, XML isn’t the fav these days.   So what are your options if you don’t like attributes, convention, or XML Configuration?  Well, Acr.ExtDirect has its own extension base to give the API a list of methods and components to make available for remote execution.  1: public interface IDirectMethodResolver { 2:   3: bool IsServiceType(ComponentModel model, Type type); 4: string GetNamespace(ComponentModel model); 5: string[] GetDirectMethodNames(ComponentModel model); 6: DirectMethodType GetMethodType(ComponentModel model, MethodInfo method); 7: }   Now to implement our own method resolver:   1: public class TestResolver : IDirectMethodResolver { 2:   3: #region IDirectMethodResolver Members 4:   5: /// <summary> 6: /// Determine if you are calling a service 7: /// </summary> 8: /// <param name="model"></param> 9: /// <param name="type"></param> 10: /// <returns></returns> 11: public bool IsServiceType(ComponentModel model, Type type) { 12: return (type.Namespace == "MyBLL.Data"); 13: } 14:   15: /// <summary> 16: /// Return the calling name for the client side 17: /// </summary> 18: /// <param name="model"></param> 19: /// <returns></returns> 20: public string GetNamespace(ComponentModel model) { 21: return model.Name; 22: } 23:   24: public string[] GetDirectMethodNames(ComponentModel model) { 25: switch (model.Name) { 26: case "Products" : 27: return new [] { 28: "GetProducts", 29: "LoadProduct", 30: "Save", 31: "Update" 32: }; 33:   34: case "Categories" : 35: return new [] { 36: "GetProducts" 37: }; 38:   39: default : 40: throw new ArgumentException("Invalid type"); 41: } 42: } 43:   44: public DirectMethodType GetMethodType(ComponentModel model, MethodInfo method) { 45: if (method.Name.StartsWith("Save") || method.Name.StartsWith("Update")) 46: return DirectMethodType.FormSubmit; 47: 48: else if (method.Name.StartsWith("Load")) 49: return DirectMethodType.FormLoad; 50:   51: else 52: return DirectMethodType.Direct; 53: } 54:   55: #endregion 56: }   And there you have it, your own custom method resolver.  Pretty easy and pretty open ended!

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  • Struts2 - How to use the Struts2 Annotations?

    - by Aaron
    I'm trying to implement the Struts 2 Annotations in my project, but I don't know how. I added the convention-plugin v 2.1.8.1 to my pom I modified the web.xml ... <init-param> <param-name>actionPackages</param-name> <param-value>org.apache.struts.helloworld.action</param-value> </init-param> ... My Action package org.apache.struts.helloworld.action; import org.apache.struts.helloworld.model.MessageStore; import com.opensymphony.xwork2.ActionSupport; import org.apache.struts2.convention.annotation.Result; import org.apache.struts2.convention.annotation.Results; @Results({ @Result(name="success", location="HelloWorld.jsp") }) public class HelloWorld extends ActionSupport { public String execute() throws Exception { messageStore = new MessageStore() ; return SUCCESS; } The jsp page from where I'm trying to use my action. <body> <h1>Welcome To Struts 2!</h1> <p><a href="<s:url action='helloWorld'/>">Hello World</a></p> </body> When I press the link associated to the action helloWorld, but it's sends me to the exactly the same page. So, from index.jsp, it's sends to index.jsp. The way it should behave: it should send me to HelloWorld.jsp. I uploaded the project (a very simple HelloWorld app) to FileFront, maybe someone sees where is the problem. http://www.filefront.com/16364385/Hello_World.zip

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  • Visual C++ Testing problem

    - by JamesMCCullum
    Hi there I have installed VisualAssert and cFix. I have been using Visual Studio C++ and programming in CLI/C++. I have a working Chess Game Program that works perfectly by itself.....and I have been studying testing and have many examples(with tutorials) I have found on the net, that compile and run in Visual Studio..... But as soon as I try and implement those tests on my chess game......I get this problem.... This is what its telling me 1>------ Build started: Project: ChessRound1, Configuration: Debug Win32 ------ 1>Compiling... 1>stdafx.cpp 1>C:\Program Files\VisualAssert\include\cfixpe.h(137) : error C3641: 'CfixpCrtInitEmbedding' : invalid calling convention '__cdecl ' for function compiled with /clr:pure or /clr:safe 1>C:\Program Files\VisualAssert\include\cfixpe.h(235) : error C4394: 'CfixpCrtInitEmbeddingRegistration' : per-appdomain symbol should not be marked with __declspec(allocate) 1>C:\Program Files\VisualAssert\include\cfixpe.h(235) : error C2393: 'CfixpCrtInitEmbeddingRegistration' : per-appdomain symbol cannot be allocated in segment '.CRT$XCX' 1>C:\Program Files\VisualAssert\include\cfixpe.h(244) : error C2440: 'initializing' : cannot convert from 'void (__cdecl *)(void)' to 'const CFIX_CRT_INIT_ROUTINE' 1> Address of a function yields __clrcall calling convention in /clr:pure and /clr:safe; consider using __clrcall in target type 1>C:\Program Files\VisualAssert\include\cfixpe.h(137) : error C3641: 'CfixpCrtInitEmbedding' : invalid calling convention '__cdecl ' for function compiled with /clr:pure or /clr:safe 1>Build log was saved at "file://c:\Users\james\Documents\Visual Studio 2008\Projects\ChessRound1\ChessRound1\Debug\BuildLog.htm" 1>ChessRound1 - 4 error(s), 0 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== Any ideas what I'm doing wrong? Im working with windows forms and have a heap of cpp source files. Any help would be appreciated. Thanks

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  • Conventions for the behavior of double or triple "click to select text" features?

    - by John Sullivan
    Almost any mature program that involves text implements "double click to select the word" and, in some cases, "triple click to select additional stuff like an entire line" as a feature. I find these features useful but they are often inconsistent between programs. Example - some programs' double clicks do not select the ending space after a word, but most do. Some recognize the - character as the end of a word, others do not. SO likes to select the entire paragraph as I write this post when I triple click it, VS web developer 2005 has no triple click support, and ultra-edit 32 will select one line upon triple clicking. We could come up with innumerable inconsistencies about how double and triple click pattern matching is implemented across programs. I am concerned about how to implement this behavior in my program if nobody else has achieved a convention about how the pattern matching should work. My question is, does a convention (conventions? maybe an MS or Linux convention?) exist that dictates how these features are supposed to behave to the end user? What, if any, are they?

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  • System Calls in windows & Native API?

    - by claws
    Recently I've been using lot of Assembly language in *NIX operating systems. I was wondering about the windows domain. Calling convention in linux: mov $SYS_Call_NUM, %eax mov $param1 , %ebx mov $param2 , %ecx int $0x80 Thats it. That is how we should make a system call in linux. Reference of all system calls in linux: Regarding which $SYS_Call_NUM & which parameters we can use this reference : http://docs.cs.up.ac.za/programming/asm/derick_tut/syscalls.html OFFICIAL Reference : http://kernel.org/doc/man-pages/online/dir_section_2.html Calling convention in Windows: ??? Reference of all system calls in Windows: ??? Unofficial : http://www.metasploit.com/users/opcode/syscalls.html , but how do I use these in assembly unless I know the calling convention. OFFICIAL : ??? If you say, they didn't documented it. Then how is one going to write libc for windows without knowing system calls? How is one gonna do Windows Assembly programming? Atleast in the driver programming one needs to know these. right? Now, whats up with the so called Native API? Is Native API & System calls for windows both are different terms referring to same thing? In order to confirm I compared these from two UNOFFICIAL Sources System Calls: http://www.metasploit.com/users/opcode/syscalls.html Native API: http://undocumented.ntinternals.net/aindex.html My observations: All system calls are beginning with letters Nt where as Native API is consisting of lot of functions which are not beginning with letters Nt. System Call of windows are subset of Native API. System calls are just part of Native API. Can any one confirm this and explain.

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  • Fast Society Creates Mini and Mobile Temporary Social Networks

    - by ETC
    You’re out on the town or at a convention with a bunch of friends. How do you keep in touch with the entire group simultaneously? Fast Society offers a smartphone-based solution: a temporary social network for group talking, texting, and more. Fast Society was originally an iPhone only application and has recently updated to include and Android app too. The premise is simple: You set up a Fast Society group, link your friends into it, and for that night (or convention weekend) you’re all part of the same mini group. You can text the entire group, share pictures, set up sub-groups (let’s say that half your group is going to stay up late and party while half need to hit the rack to get up early for presentations, you can create a new group for the night owls to communicate), share your location, and send in-app and SMS messages to the entire group. Check out the video above to see it in action or hit up the link below to read more and grab a copy. Face Society [via Mashable] Latest Features How-To Geek ETC How to Get Amazing Color from Photos in Photoshop, GIMP, and Paint.NET Learn To Adjust Contrast Like a Pro in Photoshop, GIMP, and Paint.NET Have You Ever Wondered How Your Operating System Got Its Name? Should You Delete Windows 7 Service Pack Backup Files to Save Space? What Can Super Mario Teach Us About Graphics Technology? Windows 7 Service Pack 1 is Released: But Should You Install It? Peaceful Alpine River on a Sunny Day [Wallpaper] Fast Society Creates Mini and Mobile Temporary Social Networks Page Zipper Unpacks Multi-Page Articles for Single-Page Display Minty Bug: Build an FM Bug Inside a Mint Container Get the MakeUseOf eBook Guide to Hacker Proofing Your PC Sync Your Windows Computer with Your Ubuntu One Account [Desktop Client]

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  • SQLAuthority News – Story of Seattle – SQLPASS 2011 Event Log

    - by pinaldave
    Just like every year I attended SQL PASS in Seattle earlier this month. The event was scheduled from Oct 11-14, 2011 in the convention center of the Seattle. I have been to Seattle more than 6 times so far so it is not a new city for me anymore. The city has always impressed me with its vibrant life and pleasant weather. Just like every other time, I had excellent experience once again in the city. Though I just arrived on the day of the event and left right after the event was over – I hardly visited Seattle – still some good experience to share. Here are few quick photographs from my quick trip of Seattle city. Skyline of Seattle Seattle Convention Center A Shop Tenzing Momo and Co at Pike St Market The Seattle Gum Wall Shoreline in Seattle Nigel and Paras First Starbucks (Relocated) People on Street of Seattle Food at Sandy’s – All Veg Well, this is a short summary of my extremely quick city tour of Seattle. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL PASS, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL, Technology

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  • Variable naming conventions?

    - by Ziv
    I've just started using ReSharper (for C#) and I kind of like its code smells finder, it shows me some things about my writing that I meant to fix a long time ago (mainly variable naming conventions). It caused me to reconsider some of my naming conventions for methods and instance variables. ReSharper suggests that instance variable be lower camel case and begin with an underscore. For a while I meant to make all my local variables lower camel case but is the underscore necessary? Do you find it comfortable? I don't like this convention but I also haven't tried it yet, what is you opinion of it? The second thing it prompted me to re-evaluate is my naming conventions for GUI event handlers. I usually use the VS standard of ControlName_Action and my controls usually use hungarian notation (as a suffix, to help clarify in code what is visible to the user and what isn't when dealing with similarly named variable) so I end up with OK_btn_Click(), what is your opinion of that? Should I succumb to the ReSharper convention or there are other equally valid options?

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  • EF4 CPT5 Code First Remove Cascading Deletes

    - by Dane Morgridge
    I have been using EF4 CTP5 with code first and I really like the new code.  One issue I was having however, was cascading deletes is on by default.  This may come as a surprise as using Entity Framework with anything but code first, this is not the case.  I ran into an exception with some one-to-many relationships I had: Introducing FOREIGN KEY constraint 'ProjectAuthorization_UserProfile' on table 'ProjectAuthorizations' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. Could not create constraint. See previous errors. To get around this, you can use the fluent API and put some code in the OnModelCreating: 1: protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) 2: { 3: modelBuilder.Entity<UserProfile>() 4: .HasMany(u => u.ProjectAuthorizations) 5: .WithRequired(a => a.UserProfile) 6: .WillCascadeOnDelete(false); 7: } This will work to remove the cascading delete, but I have to use the fluent API and it has to be done for every one-to-many relationship that causes the problem. I am personally not a fan of cascading deletes in general (for several reasons) and I’m not a huge fan of fluent APIs.  However, there is a way to do this without using the fluent API.  You can in the OnModelCreating, remove the convention that creates the cascading deletes altogether. 1: protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) 2: { 3: modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>(); 4: } Thanks to Jeff Derstadt from Microsoft for the info on removing the convention all together.  There is a way to build a custom attribute to remove it on a case by case basis and I’ll have a post on how to do this in the near future.

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  • Adventures in MVVM &ndash; My ViewModel Base &ndash; Silverlight Support!

    - by Brian Genisio's House Of Bilz
    More Adventures in MVVM In my last post, I outlined the powerful features that are available in the ViewModelSupport.  It takes advantage of the dynamic features of C# 4.0 (as well as some 3.0 goodies) to help eliminate the plumbing that often comes with writing ViewModels.  If you are interested in learning about the capabilities, please take a look at that post and look at the code on CodePlex.  When I wrote about the ViewModel base class, I complained that the features did not work in Silverlight because as of 4.0, it does not support binding to dynamic properties.  Although I still think this is a bummer, I am happy to say that I have come up with a workaround.  In the Silverlight version of my base class, I include a PropertyCollectionConverter that lets you bind to dynamic properties in the ViewModelBase, especially the convention-based commands that the base class supports. To take advantage of any properties that are not statically defined, you can bind to the Properties property of the ViewModel and pass in a converter parameter for the name of the property you want to bind. For example, a ViewModel that looks like this: public class ExampleViewModel : ViewModelBase { public void Execute_MyCommand() { Set("Text", "Foo"); } } Can bind to the dynamic property and the convention-based command with the following XAML. <TextBlock Text="{Binding Properties, Converter={StaticResource PropertiesConverter}, ConverterParameter=Text}" Margin="5" /> <Button Content="Execute MyCommand" Command="{Binding Properties, Converter={StaticResource PropertiesConverter}, ConverterParameter=MyCommand}" Margin="5" /> Of course, it is not as pretty as binding to Text and MyCommand like you can in WPF.  But, it is better than having a failed feature.  This allows you to share your ViewModels between WPF and Silverlight very easily.  <BeatDeadHorse>Hopefully, in Silverlight 5.0, we will see binding to dynamic properties more directly????</BeatDeadHorse>

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  • JavaOne India Early Bird Discount Ends April 2nd

    - by Tori Wieldt
    JavaOne India3-4 May, 2012Hyderabad International Convention Centre Register Now and Save – For A Limited Time!If you register by 2 April, you'll save INR 1080 on this premier Java technology conference. JavaOne will return for the second straight year to India May 3, 4 at the Hyderabad Convention Center. This year's line up will once again bring some of the leading experts in from all over the world as well as local Indian content. Sharat Chander (Director - Java Technology Outreach) said, "JavaOne is the premier Java technology conference in the world, for developers by developers.  Every year we keep increasing community participation in both the content selection and content delivery, and this year we expect even more."The JavaOne India tracks are:Client-Side Technologies and Rich User ExperiencesLearn about developments in Java for the desktop and practices for building rich, immersive, and powerful user experiences across multiple hardware platforms and form factors. Core Java PlatformDiscover the latest innovations in Java virtual machines. Get deep technical explanations in security and networking and enhancements that allow dynamic programming languages to drive Java platform adoption. Java EE Web Profile, Platform Technologies, Web Services, and the Cloud Update your knowledge on topics such as Web application development, persistence, security, and transactions. This track will also address modularity, enterprise caching, Web sockets, and internet identity. Mobile, Java Card, Embedded, and DevicesThis track is devoted to Java technology as the ultimate platform for mobile computing. It also covers embedded and device usages of Java technologies, including Java SE, Java ME, Java Card, and JavaFX. Share this event: #javaoneIndia

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  • Using prefix incremented loops in C#

    - by KChaloux
    Back when I started programming in college, a friend encouraged me to use the prefix incrementation operator ++i instead of the postfix i++, citing that there was a slight chance of better performance with no real chance of a downside. I realize this is true in C++, and it's become a general habit that I continue to do. I'm led to believe that it makes little to no difference when used in a loop in C#, regardless of data type. Apparently the ++ operator can't be overridden. Nevertheless, I like the appearance more, and don't see a direct downside to it. It did astonish a coworker just a moment ago though, he made the (fairly logical) assumption that my loop would terminate early as a result. He's a self-taught programmer, and apparently never came across the C++ convention. That made me question whether or not the equivalent behavior of pre- and post-fix increment and decrement operators in loops is well known enough. Is it acceptable for me to continue using ++i in looping constructs because of style preference, even though it has no real performance benefit? Or is it likely to cause confusion amongst other programmers? Note: This is assuming the ++i convention is used consistently throughout all code.

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  • Co-worker renamed all of my queries

    - by anon
    I don't know if I should be very irritated or what. I single handedly built over 300 queries for a large database, and developed a naming convention so I could find them later. No one else in my office even knows how to build a query, but I came in yesterday to find that all of them had been renamed. I am now having a very hard time finding things, and I am trying to figure out what to do. I spoke with the person responsible, and she just downplayed the whole thing. She said she renamed them so she can find them more easily. Unfortunately, I am the only one who knows how to build, edit, and maintain them, and the only reason she needed to find them was to test the queries. The new naming convention doesn't make sense at all, and I feel like we have taken a backwards step in the development process. What I'm trying to figure out is: 1) Am I overreacting? 2) What is the best way to handle this? I hate to mention this to my boss, but after speaking with my co-worker yesterday, I can already tell she feels like she did nothing wrong.

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  • JavaScript Class Patterns

    - by Liam McLennan
    To write object-oriented programs we need objects, and likely lots of them. JavaScript makes it easy to create objects: var liam = { name: "Liam", age: Number.MAX_VALUE }; But JavaScript does not provide an easy way to create similar objects. Most object-oriented languages include the idea of a class, which is a template for creating objects of the same type. From one class many similar objects can be instantiated. Many patterns have been proposed to address the absence of a class concept in JavaScript. This post will compare and contrast the most significant of them. Simple Constructor Functions Classes may be missing but JavaScript does support special constructor functions. By prefixing a call to a constructor function with the ‘new’ keyword we can tell the JavaScript runtime that we want the function to behave like a constructor and instantiate a new object containing the members defined by that function. Within a constructor function the ‘this’ keyword references the new object being created -  so a basic constructor function might be: function Person(name, age) { this.name = name; this.age = age; this.toString = function() { return this.name + " is " + age + " years old."; }; } var john = new Person("John Galt", 50); console.log(john.toString()); Note that by convention the name of a constructor function is always written in Pascal Case (the first letter of each word is capital). This is to distinguish between constructor functions and other functions. It is important that constructor functions be called with the ‘new’ keyword and that not constructor functions are not. There are two problems with the pattern constructor function pattern shown above: It makes inheritance difficult The toString() function is redefined for each new object created by the Person constructor. This is sub-optimal because the function should be shared between all of the instances of the Person type. Constructor Functions with a Prototype JavaScript functions have a special property called prototype. When an object is created by calling a JavaScript constructor all of the properties of the constructor’s prototype become available to the new object. In this way many Person objects can be created that can access the same prototype. An improved version of the above example can be written: function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { toString: function() { return this.name + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); In this version a single instance of the toString() function will now be shared between all Person objects. Private Members The short version is: there aren’t any. If a variable is defined, with the var keyword, within the constructor function then its scope is that function. Other functions defined within the constructor function will be able to access the private variable, but anything defined outside the constructor (such as functions on the prototype property) won’t have access to the private variable. Any variables defined on the constructor are automatically public. Some people solve this problem by prefixing properties with an underscore and then not calling those properties by convention. function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { _getName: function() { return this.name; }, toString: function() { return this._getName() + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); Note that the _getName() function is only private by convention – it is in fact a public function. Functional Object Construction Because of the weirdness involved in using constructor functions some JavaScript developers prefer to eschew them completely. They theorize that it is better to work with JavaScript’s functional nature than to try and force it to behave like a traditional class-oriented language. When using the functional approach objects are created by returning them from a factory function. An excellent side effect of this pattern is that variables defined with the factory function are accessible to the new object (due to closure) but are inaccessible from anywhere else. The Person example implemented using the functional object construction pattern is: var personFactory = function(name, age) { var privateVar = 7; return { toString: function() { return name + " is " + age * privateVar / privateVar + " years old."; } }; }; var john2 = personFactory("John Lennon", 40); console.log(john2.toString()); Note that the ‘new’ keyword is not used for this pattern, and that the toString() function has access to the name, age and privateVar variables because of closure. This pattern can be extended to provide inheritance and, unlike the constructor function pattern, it supports private variables. However, when working with JavaScript code bases you will find that the constructor function is more common – probably because it is a better approximation of mainstream class oriented languages like C# and Java. Inheritance Both of the above patterns can support inheritance but for now, favour composition over inheritance. Summary When JavaScript code exceeds simple browser automation object orientation can provide a powerful paradigm for controlling complexity. Both of the patterns presented in this article work – the choice is a matter of style. Only one question still remains; who is John Galt?

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  • JavaScript Class Patterns

    - by Liam McLennan
    To write object-oriented programs we need objects, and likely lots of them. JavaScript makes it easy to create objects: var liam = { name: "Liam", age: Number.MAX_VALUE }; But JavaScript does not provide an easy way to create similar objects. Most object-oriented languages include the idea of a class, which is a template for creating objects of the same type. From one class many similar objects can be instantiated. Many patterns have been proposed to address the absence of a class concept in JavaScript. This post will compare and contrast the most significant of them. Simple Constructor Functions Classes may be missing but JavaScript does support special constructor functions. By prefixing a call to a constructor function with the ‘new’ keyword we can tell the JavaScript runtime that we want the function to behave like a constructor and instantiate a new object containing the members defined by that function. Within a constructor function the ‘this’ keyword references the new object being created -  so a basic constructor function might be: function Person(name, age) { this.name = name; this.age = age; this.toString = function() { return this.name + " is " + age + " years old."; }; } var john = new Person("John Galt", 50); console.log(john.toString()); Note that by convention the name of a constructor function is always written in Pascal Case (the first letter of each word is capital). This is to distinguish between constructor functions and other functions. It is important that constructor functions be called with the ‘new’ keyword and that not constructor functions are not. There are two problems with the pattern constructor function pattern shown above: It makes inheritance difficult The toString() function is redefined for each new object created by the Person constructor. This is sub-optimal because the function should be shared between all of the instances of the Person type. Constructor Functions with a Prototype JavaScript functions have a special property called prototype. When an object is created by calling a JavaScript constructor all of the properties of the constructor’s prototype become available to the new object. In this way many Person objects can be created that can access the same prototype. An improved version of the above example can be written: function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { toString: function() { return this.name + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); In this version a single instance of the toString() function will now be shared between all Person objects. Private Members The short version is: there aren’t any. If a variable is defined, with the var keyword, within the constructor function then its scope is that function. Other functions defined within the constructor function will be able to access the private variable, but anything defined outside the constructor (such as functions on the prototype property) won’t have access to the private variable. Any variables defined on the constructor are automatically public. Some people solve this problem by prefixing properties with an underscore and then not calling those properties by convention. function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { _getName: function() { return this.name; }, toString: function() { return this._getName() + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); Note that the _getName() function is only private by convention – it is in fact a public function. Functional Object Construction Because of the weirdness involved in using constructor functions some JavaScript developers prefer to eschew them completely. They theorize that it is better to work with JavaScript’s functional nature than to try and force it to behave like a traditional class-oriented language. When using the functional approach objects are created by returning them from a factory function. An excellent side effect of this pattern is that variables defined with the factory function are accessible to the new object (due to closure) but are inaccessible from anywhere else. The Person example implemented using the functional object construction pattern is: var john = new Person("John Galt", 50); console.log(john.toString()); var personFactory = function(name, age) { var privateVar = 7; return { toString: function() { return name + " is " + age * privateVar / privateVar + " years old."; } }; }; var john2 = personFactory("John Lennon", 40); console.log(john2.toString()); Note that the ‘new’ keyword is not used for this pattern, and that the toString() function has access to the name, age and privateVar variables because of closure. This pattern can be extended to provide inheritance and, unlike the constructor function pattern, it supports private variables. However, when working with JavaScript code bases you will find that the constructor function is more common – probably because it is a better approximation of mainstream class oriented languages like C# and Java. Inheritance Both of the above patterns can support inheritance but for now, favour composition over inheritance. Summary When JavaScript code exceeds simple browser automation object orientation can provide a powerful paradigm for controlling complexity. Both of the patterns presented in this article work – the choice is a matter of style. Only one question still remains; who is John Galt?

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  • org.apache.struts2.dispatcher.Dispatcher: Could not find action or result Error

    - by peterwkc
    i tried to code the following simple struts but encounter this error during run time. [org.apache.struts2.dispatcher.Dispatcher] Could not find action or result: No result defined for action com.peter.action.LoginAction and result success index.jsp <%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <%@ taglib prefix="s" uri="/struts-tags" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Struts Tutorial</title> </head> <body> <h2>Hello Struts</h2> <s:form action="login" > <s:textfield name="username" label="Username:" /> <s:password name="password" label="Password:"/> <s:submit /> </s:form> </body> </html> LoginAction.java /** * */ package com.peter.action; //import org.apache.struts2.convention.annotation.Namespace; import org.apache.struts2.convention.annotation.ResultPath; import org.apache.struts2.convention.annotation.Result; import org.apache.struts2.convention.annotation.Action; import com.opensymphony.xwork2.ActionSupport; /** * @author nicholas_tse * */ //@Namespace("/") To define URL namespace @ResultPath("/") // To instruct Struts where to search result page(jsp) public class LoginAction extends ActionSupport { private String username, password; /** * */ private static final long serialVersionUID = -8992836566328180883L; /** * */ public LoginAction() { // TODO Auto-generated constructor stub } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } @Override @Action(value = "login", results = {@Result(name="success", location="welcome.jsp")}) public String execute() { return SUCCESS; } } /* Remove * struts2-gxp-plugin * struts2-portlet-plugin * struts2-jsf-plugin * struts2-osgi-plugin and its related osgi-plugin * struts-rest-plugin * * Add * velocity-tools-view * * */ web.xml <?xml version="1.0" encoding="UTF-8"?> <web-app id="WebApp_ID" version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <display-name>Struts</display-name> <!-- org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter org.apache.struts2.dispatcher.FilterDispatcher --> <filter> <filter-name>Struts_Filter</filter-name> <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class> <init-param> <param-name>actionPackages</param-name> <param-value>com.peter.action</param-value> </init-param> </filter> <filter-mapping> <filter-name>Struts_Filter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app> Besides the runtime error, there is deployment error which is ERROR [com.opensymphony.xwork2.util.finder.ClassFinder] (MSC service thread 1-2) Unable to read class [WEB-INF.classes.com.peter.action.LoginAction]: Could not load WEB-INF/classes/com/peter/action/LoginAction.class - [unknown location] at com.opensymphony.xwork2.util.finder.ClassFinder.readClassDef(ClassFinder.java:785) [xwork-core-2.3.1.2.jar:2.3.1.2] AFAIK, the scanning methodology of struts will scan the default packages named struts2 for any annotated class but i have instructed struts2 to scan in com.peter.action using init-param but still unable to find the class. It is pretty weird. Please help. Thanks.

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  • Is there an algorithm for converting quaternion rotations to Euler angle rotations?

    - by Will Baker
    Is there an existing algorithm for converting a quaternion representation of a rotation to an Euler angle representation? The rotation order for the Euler representation is known and can be any of the six permutations (i.e. xyz, xzy, yxz, yzx, zxy, zyx). I've seen algorithms for a fixed rotation order (usually the NASA heading, bank, roll convention) but not for arbitrary rotation order. Furthermore, because there are multiple Euler angle representations of a single orientation, this result is going to be ambiguous. This is acceptable (because the orientation is still valid, it just may not be the one the user is expecting to see), however it would be even better if there was an algorithm which took rotation limits (i.e. the number of degrees of freedom and the limits on each degree of freedom) into account and yielded the 'most sensible' Euler representation given those constraints. I have a feeling this problem (or something similar) may exist in the IK or rigid body dynamics domains. Solved: I just realised that it might not be clear that I solved this problem by following Ken Shoemake's algorithms from Graphics Gems. I did answer my own question at the time, but it occurs to me it may not be clear that I did so. See the answer, below, for more detail. Just to clarify - I know how to convert from a quaternion to the so-called 'Tait-Bryan' representation - what I was calling the 'NASA' convention. This is a rotation order (assuming the convention that the 'Z' axis is up) of zxy. I need an algorithm for all rotation orders. Possibly the solution, then, is to take the zxy order conversion and derive from it five other conversions for the other rotation orders. I guess I was hoping there was a more 'overarching' solution. In any case, I am surprised that I haven't been able to find existing solutions out there. In addition, and this perhaps should be a separate question altogether, any conversion (assuming a known rotation order, of course) is going to select one Euler representation, but there are in fact many. For example, given a rotation order of yxz, the two representations (0,0,180) and (180,180,0) are equivalent (and would yield the same quaternion). Is there a way to constrain the solution using limits on the degrees of freedom? Like you do in IK and rigid body dynamics? i.e. in the example above if there were only one degree of freedom about the Z axis then the second representation can be disregarded. I have tracked down one paper which could be an algorithm in this pdf but I must confess I find the logic and math a little hard to follow. Surely there are other solutions out there? Is arbitrary rotation order really so rare? Surely every major 3D package that allows skeletal animation together with quaternion interpolation (i.e. Maya, Max, Blender, etc) must have solved exactly this problem?

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  • Naming conventions and field naming question for CakePHP

    - by jphenow
    Okay so two questions very related: 1) Does following the naming convention for classes, controllers, database fields, etc. affect the framework's ability to work the way it was intended? (I'm a little new to working with a framework from the beginning of app development) 2) This question is more important if 1 is a yes. Say I have a table, A, that has 2 foreign keys pointing at the same table, B, but different entries (they're like edges of a graph that point at two vertices) how would I follow the naming convention of their database fields? All I can think to do is something like vertex_1_id and vertex_2_id but I don't know how the framework would handle that if the naming conventions are necessary for its functioning correctly.

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  • Why use I-prefix for interfaces in Java?

    - by Lars Andren
    Is there some reason why people use I-prefix for interfaces in Java? It seems to be a C#-convention spilling over. For C# it makes sense, as the answers to this question explains. However, for Java a class declaration clearly states which class that is extended and which interfaces that are implemented: public class Crow extends Animal implements Bird I think Joshua Bloch didn't suggest this in Effective Java, and I think he usually makes a lot of sense. I get the I-verbing as presented in an answer to the question above, but is there some other use with this convention for Java?

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  • Python Core Library and PEP8

    - by Szymon Guz
    I was trying to understand why Python is said to be a beautiful language. I was directed to the beauty of PEP 8... and it was strange. In fact it says that you can use any convention you want, just be consistent... and suddenly I found some strange things in the core library: request() getresponse() set_debuglevel() endheaders() http://docs.python.org/py3k/library/http.client.html The below functions are new in the Python 3.1. What part of PEP 8 convention is used here? popitem() move_to_end() http://docs.python.org/py3k/library/collections.html So my question is: is PEP 8 used in the core library, or not? Why is it like that? Is there the same situation as in PHP where I cannot just remember the name of the function because there are possible all ways of writing the name? Why PEP 8 is not used in the core library even for the new functions?

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  • variable names in function definition, call and declaration

    - by yCalleecharan
    Hi, I see C books that use the same variable names in the function definition, calling function and declaration. Others use the same variable names in the calling function and in the declaration/prototype but a different one in the definition as in: void blabla(int something); //prototype blabla(something) // calling function inside main after something has been initialized to int void blabla(int something_else) //definition I have two questions: What convention is best to use in C?; Does the convention apply regardless whether a value is being passed "by-value" or if it's being passed by a pointer? Thanks a lot...

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  • Interface naming in Java

    - by Allain Lalonde
    Most OO languages prefix their interface names with a capital I, why does Java not do this? What was the rationale for not following this convention? To demonstrate what I mean, if I wanted to have a User interface and a User implementation I'd have two choices in Java: Class = User, Interface = UserInterface Class = UserImpl, Interface = User Where in most languages: Class = User, Interface = IUser Now, you might argue that you could always pick a most descriptive name for the user implementation and the problem goes away, but Java's pushing a POJO approach to things and most IOC containers use DynamicProxies extensively. These two things together mean that you'll have lots of interfaces with a single POJO implementation. So, I guess my question boils down to: "Is it worth following the broader Interface naming convention especially in light of where Java Frameworks seem to be heading?"

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  • Java Spring 3.0 MVC Annotation vs COC. Whats the preferred method in the Java community?

    - by Athens
    I am using Spring's MVC framework for an application I'm hosting on Google's App Engine. So far, my controllers are registered via the @Controller annotation; however, prior to getting into Spring, I evaluated ASP.net MVC 2 which requires no configuration and is based on convention. Is convention over configuration (COC) the current and preferred method in the Java community to implement MVC with Spring. Also, this may be a result of my limited knowledge so far but i noticed that i could only instantiate my Controllers the required constuctor injection if i use the COC method via the ControllerClassNameHandlerMapping. For instance the following controller bean config will fail if i use the defaultannotationhandlermapping. <bean id="c" class="com.domain.TestController"> <constructor-arg ref="service" /> </bean> <bean id="service" class="com.domain.Service" /> My com.domain.TestController controller works fine if i use ControllerClassNameHandlerMapping/COC but it results in an error when i use defaultannotationhandlermapping/Annotations.

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  • Java Spring 3.0 MVC Annotation vs COC. Whats the prefered method in the Java community?

    - by Athens
    I am using Spring's MVC framework for an application I'm hosting on Google's App Engine. So far, my controllers are registered via the @Controller annotation; however, prior to getting into Spring, I evaluated ASP.net MVC 2 which requires no configuration and is based on convention. Is convention over configuration (COC) the current and preferred method in the Java community to implement MVC with Spring. Also, this may be a result of my limited knowledge so far but i noticed that i could only instantiate my Controllers the required constuctor injection if i use the COC method via the ControllerClassNameHandlerMapping. For instance the following controller bean config will fail if i use the defaultannotationhandlermapping. My com.domain.TestController controller works fine if i use ControllerClassNameHandlerMapping/COC but it results in an error when i use defaultannotationhandlermapping/Annotations.

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