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  • Apply PHP regex replace on a multi-line repeted pattern

    - by Hussain
    Let's say I have this input: I can haz a listz0rs! # 42 # 126 I can haz another list plox? # Hello, world! # Welcome! I want to split it so that each set of hash-started lines becomes a list: I can haz a listz0rs! <ul> <li>42</li> <li>126</li> </ul> I can haz another list plox? <ul> <li>Hello, world!</li> <li>Welcome!</li> </ul> If I run the input against the regex "/(?:(?:(?<=^# )(.*)$)+)/m", I get the following result: Array ( [0] => Array ( [0] => 42 ) Array ( [0] => 126 ) Array ( [0] => Hello, world! ) Array ( [0] => Welcome! ) ) This is fine and dandy, but it doesn't distinguish between the two different lists. I need a way to either make the quantifier return a concatenated string of all the occurrences, or, ideally, an array of all the occurrences. Idealy, this should be my output: Array ( [0] = Array ( [0] = 42 [1] = 126 ) Array ( [0] = Hello, world! [1] = Welcome! ) ) Is there any way of achieving this, and if not, is there a close alternative? Thanks in advance!

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  • Regex and Pattern Matching in Scala

    - by Bruce Ferguson
    I am not strong in regex, and pretty new to Scala. I would like to be able to find a match between the first letter of a word, and one of the letters in a group such as "ABC". In pseudocode, this might look something like: case Process(word) => word.firstLetter match { case([a-c][A-C]) => case _ => } } but I don't know how to grab the first letter in Scala instead of Java, how to express the regular expression properly, nor if it's possible to do this within a case class. Any suggestions? Thanks in advance. Bruce

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  • Building a control-flow graph from an AST with a visitor pattern using Java

    - by omegatai
    Hi guys, I'm trying to figure out how to implement my LEParserCfgVisitor class as to build a control-flow graph from an Abstract-Syntax-Tree already generated with JavaCC. I know there are tools that already exist, but I'm trying to do it in preparation for my Compilers final. I know I need to have a data structure that keeps the graph in memory, and I want to be able to keep attributes like IN, OUT, GEN, KILL in each node as to be able to do a control-flow analysis later on. My main problem is that I haven't figured out how to connect the different blocks together, as to have the right edge between each blocks depending on their nature: branch, loops, etc. In other words, I haven't found an explicit algorithm that could help me build my visitor. Here is my empty Visitor. You can see it works on basic langage expressions, like if, while and basic operations (+,-,x,^,...) public class LEParserCfgVisitor implements LEParserVisitor { public Object visit(SimpleNode node, Object data) { return data; } public Object visit(ASTProgram node, Object data) { data = node.childrenAccept(this, data); return data; } public Object visit(ASTBlock node, Object data) { } public Object visit(ASTStmt node, Object data) { } public Object visit(ASTAssignStmt node, Object data) { } public Object visit(ASTIOStmt node, Object data) { } public Object visit(ASTIfStmt node, Object data) { } public Object visit(ASTWhileStmt node, Object data) { } public Object visit(ASTExpr node, Object data) { } public Object visit(ASTAddExpr node, Object data) { } public Object visit(ASTFactExpr node, Object data) { } public Object visit(ASTMultExpr node, Object data) { } public Object visit(ASTPowerExpr node, Object data) { } public Object visit(ASTUnaryExpr node, Object data) { } public Object visit(ASTBasicExpr node, Object data) { } public Object visit(ASTFctExpr node, Object data) { } public Object visit(ASTRealValue node, Object data) { } public Object visit(ASTIntValue node, Object data) { } public Object visit(ASTIdentifier node, Object data) { } } Can anyone give me a hand? Thanks!

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  • F# pattern matching when mixing DU's and other values

    - by Roger Alsing
    What would be the most effective way to express the following code? match cond.EvalBool() with | true -> match body.Eval() with | :? ControlFlowModifier as e -> match e with | Break(scope) -> e :> obj //Break is a DU element of ControlFlowModifier | _ -> next() //other members of CFM should call next() | _ -> next() //all other values should call next() | false -> null cond.EvalBool returns a boolean result where false should return null and true should either run the entire block again (its wrapped in a func called next) or if the special value of break is found, then the loop should exit and return the break value. Is there any way to compress that block of code to something smaller?

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  • Apply PHP regex replace on a multi-line repeated pattern

    - by Hussain
    Let's say I have this input: I can haz a listz0rs! # 42 # 126 I can haz another list plox? # Hello, world! # Welcome! I want to split it so that each set of hash-started lines becomes a list: I can haz a listz0rs! <ul> <li>42</li> <li>126</li> </ul> I can haz another list plox? <ul> <li>Hello, world!</li> <li>Welcome!</li> </ul> If I run the input against the regex "/(?:(?:(?<=^# )(.*)$)+)/m", I get the following result: Array ( [0] => Array ( [0] => 42 ) [1] => Array ( [0] => 126 ) [2] => Array ( [0] => Hello, world! ) [3] => Array ( [0] => Welcome! ) ) This is fine and dandy, but it doesn't distinguish between the two different lists. I need a way to either make the quantifier return a concatenated string of all the occurrences, or, ideally, an array of all the occurrences. Ideally, this should be my output: Array ( [0] => Array ( [0] => 42 [1] => 126 ) [1] => Array ( [0] => Hello, world! [1] => Welcome! ) ) Is there any way of achieving this, and if not, is there a close alternative? Thanks in advance!

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  • Problem updating through LINQtoSQL in MVC application using StructureMap, Repository Pattern and UoW

    - by matt
    I have an ASP MVC application using LINQ to SQL for data access. I am trying to use the Repository and Unit of Work patterns, with a service layer consuming the repositories and unit of work. I am experiencing a problem when attempting to perform updates on a particular repository. My application architecture is as follows: My service class: public class MyService { private IRepositoryA _RepositoryA; private IRepositoryB _RepositoryB; private IUnitOfWork _unitOfWork; public MyService(IRepositoryA ARepositoryA, IRepositoryB ARepositoryB, IUnitOfWork AUnitOfWork) { _unitOfWork = AUnitOfWork; _RepositoryA = ARepositoryA; _RepositoryB = ARepositoryB; } public PerformActionOnObject(Guid AID) { MyObject obj = _RepositoryA.GetRecords() .WithID(AID); obj.SomeProperty = "Changed to new value"; _RepositoryA.UpdateRecord(obj); _unitOfWork.Save(); } } Repository interface: public interface IRepositoryA { IQueryable<MyObject> GetRecords(); UpdateRecord(MyObject obj); } Repository LINQtoSQL implementation: public class LINQtoSQLRepositoryA : IRepositoryA { private MyDataContext _DBContext; public LINQtoSQLRepositoryA(IUnitOfWork AUnitOfWork) { _DBConext = AUnitOfWork as MyDataContext; } public IQueryable<MyObject> GetRecords() { return from records in _DBContext.MyTable select new MyObject { ID = records.ID, SomeProperty = records.SomeProperty } } public bool UpdateRecord(MyObject AObj) { MyTableRecord record = (from u in _DB.MyTable where u.ID == AObj.ID select u).SingleOrDefault(); if (record == null) { return false; } record.SomeProperty = AObj.SomePropery; return true; } } Unit of work interface: public interface IUnitOfWork { void Save(); } Unit of work implemented in data context extension. public partial class MyDataContext : DataContext, IUnitOfWork { public void Save() { SubmitChanges(); } } StructureMap registry: public class DataServiceRegistry : Registry { public DataServiceRegistry() { // Unit of work For<IUnitOfWork>() .HttpContextScoped() .TheDefault.Is.ConstructedBy(() => new MyDataContext()); // RepositoryA For<IRepositoryA>() .Singleton() .Use<LINQtoSQLRepositoryA>(); // RepositoryB For<IRepositoryB>() .Singleton() .Use<LINQtoSQLRepositoryB>(); } } My problem is that when I call PerformActionOnObject on my service object, the update never fires any SQL. I think this is because the datacontext in the UnitofWork object is different to the one in RepositoryA where the data is changed. So when the service calls Save() on it's IUnitOfWork, the underlying datacontext does not have any updated data so no update SQL is fired. Is there something I've done wrong in the StrutureMap registry setup? Or is there a more fundamental problem with the design? Many thanks.

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  • Complex pattern replacement using PHP preg_replace function ignoring quoted strings

    - by Saiful
    Consider the following string: this is a STRING WHERE some keywords ARE available. 'i need TO format the KEYWORDS from the STRING' In the above string keywords are STRING and WHERE Now i need to get an output as follows: this is a <b>STRING</b> <b>WHERE</b> some keywords ARE available. 'i need TO format the KEYWORDS from the STRING' So that the html output will be like: this is a STRING WHERE some keywords ARE available. 'i need TO format the KEYWORDS from the STRING' Note that the keywords within a quoted ('...') string will be ignored. in the above example i ignored the STRING keyword within the quoted string. Please give a modified version of the following PHP script so that I can have my desired result as above : $patterns = array('/STRING/','/WHERE/'); $replaces = array('<b>STRING</b>', '<b>WHERE</b>'); $string = "this is a STRING WHERE some keywords ARE available. 'i need TO format the KEYWORDS from the STRING'"; preg_replace($patterns, $replaces, $string);

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  • How do I rotate a view in Interface Builder?

    - by thekevinscott
    Hello, I realize this is a painfully noob question but I just don't know what to do. I'm trying to rotate my view in Interface Builder, and everyone refers to the rotate icon in the top right of the view. My Interface Builder doesn't have this icon. See screenshot: What am I doing wrong? Do I have to enable this in preferences or something? I'm using Interface Builder 3.2.2

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  • java - check if string ends with certain pattern

    - by The Learner
    I have string like: This.is.a.great.place.too.work. (or) This/is/a/great/place/too/work/ than my java program should give me that the sentence is valid and it has "work". if i Have : This.is.a.great.place.too.work.hahahha (or) This/is/a/great/place/too/work/hahahah Should not give me that there is a work in the sentance. so I am looking at java strings to find a word at the end of the sentance having . (or),(or)/ before it. How can I achieve that

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  • Best Practice, objects design ASP.NET MVC

    - by DoomStone
    Hello Stackoverflow I have a code design question that have been torbeling me for a while, you see I’m doing a refactoring of my website Cosplay Denmark, a site where cospalyers can upload images of them self in their costumes. The original site was done in php, Zend MVC, but my refactoring is being done in ASP.NET MVC 2. If you take the site http://www.cosplaydanmark.dk/Costumes/ (You can switch to English in the left column (Sprog)) Here you see a list of all the anime’s we have on the site with images, we show the name, how many different characters and how many images there are under this anime. http://www.cosplaydanmark.dk/Costumes/Bleach If you click on an anime will you get a list of characters within the given anime which we have images in, here do we show the character name, how many galleries and how many images. http://www.cosplaydanmark.dk/Costumes/Bleach/Ichigo_Kurosaki/ If you click on the character name, will you get a list of the galleries under the given character in the given anime. Here we have some information about the gallery, such as image count. http://www.cosplaydanmark.dk/Costumes/Bleach/Ichigo_Kurosaki/Admi/ Should you click the gallery do you get a list of the images in the gallery. My database look like this at the moment. As you can might imagine there are a lot of different query’s to create the site, on the first site I need to do a select on the on the “animes” table and for each result, I need to do a count select on characters and galleries. My plan to create this will be one of the following Where the IList, would be a lazy load list. But I can’t decide what would be the best solution for this would be, also if there is a better way of doing this. My priority is to have good performance with a minimum lose of features and code upkeep. I’m using a service pattern with a linq to sql repository. My design is not absolute, I’m willing to change it if it could increase performance :D I hope that I have describe my question good enough for you to understand what I mean, but ask away if there are anything I have missed.

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  • Does my use of the strategy pattern violate the fundamental MVC pattern in iOS?

    - by Goodsquirrel
    I'm about to use the 'strategy' pattern in my iOS app, but feel like my approach violates the somehow fundamental MVC pattern. My app is displaying visual "stories", and a Story consists (i.e. has @properties) of one Photo and one or more VisualEvent objects to represent e.g. animated circles or moving arrows on the photo. Each VisualEvent object therefore has a eventType @property, that might be e.g. kEventTypeCircle or kEventTypeArrow. All events have things in common, like a startTime @property, but differ in the way they are being drawn on the StoryPlayerView. Currently I'm trying to follow the MVC pattern and have a StoryPlayer object (my controller) that knows about both the model objects (like Story and all kinds of visual events) and the view object StoryPlayerView. To chose the right drawing code for each of the different visual event types, my StoryPlayer is using a switch statement. @implementation StoryPlayer // (...) - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { switch (event.eventType) { case kEventTypeCircle: [self showCircleEvent:event onStoryPlayerView:storyPlayerView]; break; case kEventTypeArrow: [self showArrowDrawingEvent:event onStoryPlayerView:storyPlayerView]; break; // (...) } But switch statements for type checking are bad design, aren't they? According to Uncle Bob they lead to tight coupling and can and should almost always be replaced by polymorphism. Having read about the "Strategy"-Pattern in Head First Design Patterns, I felt this was a great way to get rid of my switch statement. So I changed the design like this: All specialized visual event types are now subclasses of an abstract VisualEvent class that has a showOnStoryPlayerView: method. @interface VisualEvent : NSObject - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView; // abstract Each and every concrete subclass implements a concrete specialized version of this drawing behavior method. @implementation CircleVisualEvent - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView { [storyPlayerView drawCircleAtPoint:self.position color:self.color lineWidth:self.lineWidth radius:self.radius]; } The StoryPlayer now simply calls the same method on all types of events. @implementation StoryPlayer - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { [event showOnStoryPlayerView:storyPlayerView]; } The result seems to be great: I got rid of the switch statement, and if I ever have to add new types of VisualEvents in the future, I simply create new subclasses of VisualEvent. And I won't have to change anything in StoryPlayer. But of cause this approach violates the MVC pattern since now my model has to know about and depend on my view! Now my controller talks to my model and my model talks to the view calling methods on StoryPlayerView like drawCircleAtPoint:color:lineWidth:radius:. But this kind of calls should be controller code not model code, right?? Seems to me like I made things worse. I'm confused! Am I completely missing the point of the strategy pattern? Is there a better way to get rid of the switch statement without breaking model-view separation?

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  • Java Spotlight Episode 78: Jasper Potts on the JavaFX Scene Builder

    - by Roger Brinkley
    Tweet An interview with Jasper Potts about the new JavaFX Scene Builder. Joining us this week on the Java All Star Developer Panel are Dalibor Topic, Java Free and Open Source Software Ambassador and Arun Gupta, Java EE Guy. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link:  Java Spotlight Podcast in iTunes. Show Notes News JavaFX Scene Builder Developer Preview available for testing. Java EE Unlock the Java EE 6 Platform using NetBeans 7.1 Tuning GlassFish for Production JSF 2.2 Update from Ed Burns John Rose at Microsoft's Lang.NEXT summit Recording of John's Java 8 presentation Jeroen Frijters' presentation on IKVM.NET Martin Odersky's keynote JVM Language Summit 2012 July 30 – August 1; Oracle Santa Clara (same as last year) CFP coming in a few days JVM Language Summit 2011 Presentations & Recordings Proposed development schedule for JDK 8 Say hello to Mathias Axelsson Events April 11, Cleveland JUG, Cleveland, OH April 12, GreenJUG, Greenville, SC April 17-18, JavaOne Russia, Moscow Russia April 18–20, Devoxx France, Paris, France April 17-20, GIDS, Bangalore April 21, Java Summit, Chennai April 26, Mix-IT, Lyon, France, May 3-4, JavaOne India, Hyderabad, India May 5, Bangalore, Pune, ?? - JUG outreach May 7, OTN Developer Day, Mumbai May 8, OTN Developer Day, Delhi Feature InterviewJasper Potts is the Developer Experience Architect for the Java Client Group at Oracle. Responsible for technical design for everything thats sis on the core platform including Controls, Tools, Samples and Blueprints. Formally a lead engineer on the JavaFX & Swing teams working on the new JavaFX UI Controls and Graphics frameworks. Also responsible for designing, developing and presenting demos during the keynotes at JavaOne and Devoxx. A JavaOne Rockstar presenter having presented many sessions on JavaFX and Swing at many conferences. Prior to Sun he founded Xerto a desktop applications company developing Imagery a Java professional photo management application. In this interview Jasper talks about the recently release JavaFX Scene Builder. Mail Bag What’s Cool Contribute to GlassFish in Five Different Ways Stephen Chin and James Weaver join Oracle Adam Bien - Building Java FX 2 Libraries From Source With Maven 3 Paul Sandoz - Java Boomerang Building Jigsaw on Mac OS X using VirtualBox Mandy Chung: Jigsaw for Mac OS X

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  • APEX Tabs als Pulldown-Menü: wie im Application Builder

    - by carstenczarski
    Jeder kennt die Reiterkarten im APEX Application Builder, mit der eleganten Möglichkeit, das Untermenü als Pulldown-Menü aufzuklappen. Und viele fragen sich, wie man sowas in eigenen APEX-Anwendungen verwenden könnte. Spätestens, wenn man dabei noch mehr als eine Hiararchieebene unterstützen möchte, kommen APEX Reiterkarten (Tabs) nicht mehr in Frage, denn diese unterstützen nur zwei Ebenen. Im Internet findet sich der eine oder andere Tipp zum Thema; allerdings basieren viele dieser Tipps auf den JavaScript-Funktionen, die auch der Application Builder intern verwendet. Allerdings sind diese nicht dokumentiert - man kann sich also nicht darauf verlassen, dass der Ansatz in künftigen APEX-Versionen noch funktioniert. Besser ist es also, eine Lösung zu erstellen, die keinerlei Abhängigkeiten zu undokumentierten Funktionen hat. Dieser Tipp stellt eine Lösung auf der Basis von APEX-Listen vor. Listen haben den Vorteil, dass Sie beliebig geschachtelt werden können, bei Klick können sie auf beliebige Ziele verweisen und mit Listentemplates kann die Darstellung ebenfalls beliebig gestaltet werden. Mehr dazu in unserem aktuellen Tipp.

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  • The Dispose Pattern (and FxCop warnings)

    - by Scott Dorman
    [This is actually a response to Bill’s blog post, but since it isn’t possible to leave this as a comment on his blog it’s a post here.] There are many different ways to implement the Dispose pattern correctly. Some are (in my opinion) better than others. In Bill’s blog post he presents a particular pattern, which is an excerpt from his book (Effective C#). The issue centers around the fact that a reader took the code sample presented in the book and ran FxCop (Code Analysis) on it, which generated a warning: “Ensure that base.Dispose() is always called.” The “lesson learned” that Bill presents is that “tools are there to help us, not control us.” While I completely agree with the belief that tools are there to help us, I think it’s important to understand why FxCop is raising this particular warning. The code presented in Bill’s book looks like: // Have its own disposed flag.private bool disposed = false;protected override void Dispose(bool isDisposing){ // Don't dispose more than once. if (disposed) return; if (isDisposing) { // TODO: free managed resources here. } // TODO: free unmanaged resources here. // Let the base class free its resources. // Base class is responsible for calling // GC.SuppressFinalize( ) base.Dispose(isDisposing); // Set derived class disposed flag: disposed = true;} This code does follow all of the guidelines for implementing the Dispose pattern. In this case, it’s presumably part of a larger example showing how to implement the pattern as part of a base class. The reason FxCop is warning you about this code is the first if statement in the Dispose method, which will cause the method to exit if disposed is true. The problem here is that there is the possibility that if the disposed flag is true, the call to base.Dispose() will never be executed. As Bill points out, it is possible for some other code elsewhere in the class to set this flag. He states that this is an “unlikely occurrence.” While that is probably true, it can be a potentially dangerous assumption to make and is one that can be easily corrected. By changing the code slightly you can remove this assumption and correct the FxCop violation. private bool disposed = false;protected override void Dispose(bool disposing){ if (!disposed) { if (disposing) { // Dispose managed resources. } // Dispose unmanaged resources. disposed = true; } base.Dispose(disposing);} Using this implementation allows the call to base.Dispose() to always occur, which ensures that the the disposal chain is always properly followed. Technorati Tags: .NET,C#,Dispose Pattern

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  • C# String builder, displaying data nicely spaced out.

    - by Sef
    Hello, I am wondering how exactly can i order my date nicely in a stringbuilder? Meaning something equal to ("{0,2}", ....) to space the data nicely out. I do not want to use consolewrites of any kind, so the class can be re-used in a form, console code etc... Currently i am using " " for the spacing, but in overall it does not give a proper display. (it messed up when i have numbers with more then 1 digit) public override string ToString() { StringBuilder builder = new StringBuilder(); foreach (int value in tabel) { builder.Append(value); // should have something similiar to ("{0,2}", ....) builder.Append(" "); // should have something similiar to ("{0,2}", ....) } builder.Append("(top:"); builder.Append(top); builder.Append(")"); return builder.ToString(); }/*ToString*/ Regards.

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  • Pattern for Accessing MySQL connection

    - by Dipan Mehta
    We have an application which is C++ trying to access MySQL database. There are several (about 5 or so) threads in the application (with Boost library for threading) and in each thread has a few objects, each of which is trying to access Database for its' own purpose. It has a simple ORM kind of model but that really is not an important factor here. There are three potential access patterns i can think of: There could be single connection object per application or thread and is shared between all (or group). The object needs to be thread safe and there will be contentions but MySQL will not be fired with too many connections. Every object could initiate connection on its own. The database needs to take care of concurrency (which i think MySQL can) and the design could be much simpler. There could be two possibilities here. a. either object keeps a persistent connection for its life OR b. object initiate connection as and when needed. To simplify the contention as in case of 1 and not to create too many sockets as in case of 2, we can have group/set based connections. So there could be there could be more than one connection (say N), each of this connection could be shared connection across M objects. Naturally, each of the pattern has different resource cost and would work under different constraints and objectives. What criteria should i use to choose the pattern of this for my own application? What are some of the advantages and disadvantages of each of these pattern over the other? Are there any other pattern which is better? PS: I have been through these questions: mysql, one connection vs multiple and MySQL with mutiple threads and processes But they don't quite answer exactly what i am trying to ask.

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  • Using visitor pattern with large object hierarchy

    - by T. Fabre
    Context I've been using with a hierarchy of objects (an expression tree) a "pseudo" visitor pattern (pseudo, as in it does not use double dispatch) : public interface MyInterface { void Accept(SomeClass operationClass); } public class MyImpl : MyInterface { public void Accept(SomeClass operationClass) { operationClass.DoSomething(); operationClass.DoSomethingElse(); // ... and so on ... } } This design was, however questionnable, pretty comfortable since the number of implementations of MyInterface is significant (~50 or more) and I didn't need to add extra operations. Each implementation is unique (it's a different expression or operator), and some are composites (ie, operator nodes that will contain other operator/leaf nodes). Traversal is currently performed by calling the Accept operation on the root node of the tree, which in turns calls Accept on each of its child nodes, which in turn... and so on... But the time has come where I need to add a new operation, such as pretty printing : public class MyImpl : MyInterface { // Property does not come from MyInterface public string SomeProperty { get; set; } public void Accept(SomeClass operationClass) { operationClass.DoSomething(); operationClass.DoSomethingElse(); // ... and so on ... } public void Accept(SomePrettyPrinter printer) { printer.PrettyPrint(this.SomeProperty); } } I basically see two options : Keep the same design, adding a new method for my operation to each derived class, at the expense of maintainibility (not an option, IMHO) Use the "true" Visitor pattern, at the expense of extensibility (not an option, as I expect to have more implementations coming along the way...), with about 50+ overloads of the Visit method, each one matching a specific implementation ? Question Would you recommand using the Visitor pattern ? Is there any other pattern that could help solve this issue ?

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  • MVC Architecture

    Model-View-Controller (MVC) is an architectural design pattern first written about and implemented by  in 1978. Trygve developed this pattern during the year he spent working with Xerox PARC on a small talk application. According to Trygve, “The essential purpose of MVC is to bridge the gap between the human user's mental model and the digital model that exists in the computer. The ideal MVC solution supports the user illusion of seeing and manipulating the domain information directly. The structure is useful if the user needs to see the same model element simultaneously in different contexts and/or from different viewpoints.”  Trygve Reenskaug on MVC The MVC pattern is composed of 3 core components. Model View Controller The Model component referenced in the MVC pattern pertains to the encapsulation of core application data and functionality. The primary goal of the model is to maintain its independence from the View and Controller components which together form the user interface of the application. The View component retrieves data from the Model and displays it to the user. The View component represents the output of the application to the user. Traditionally the View has read-only access to the Model component because it should not change the Model’s data. The Controller component receives and translates input to requests on the Model or View components. The Controller is responsible for requesting methods on the model that can change the state of the model. The primary benefit to using MVC as an architectural pattern in a project compared to other patterns is flexibility. The flexibility of MVC is due to the distinct separation of concerns it establishes with three distinct components.  Because of the distinct separation between the components interaction is limited through the use of interfaces instead of classes. This allows each of the components to be hot swappable when the needs of the application change or needs of availability change. MVC can easily be applied to C# and the .Net Framework. In fact, Microsoft created a MVC project template that will allow new project of this type to be created with the standard MVC structure in place before any coding begins. The project also creates folders for the three key components along with default Model, View and Controller classed added to the project. Personally I think that MVC is a great pattern in regards to dealing with web applications because they could be viewed from a myriad of devices. Examples of devices include: standard web browsers, text only web browsers, mobile phones, smart phones, IPads, IPhones just to get started. Due to the potentially increasing accessibility needs and the ability for components to be hot swappable is a perfect fit because the core functionality of the application can be retained and the View component can be altered based on the client’s environment and the View component could be swapped out based on the calling device so that the display is targeted to that specific device.

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  • iOS - Unit tests for KVO/delegate codes

    - by ZhangChn
    I am going to design a MVC pattern. It could be either designed as a delegate pattern, or a Key-Value-Observing(KVO), to notify the controller about changing models. The project requires certain quality control procedures to conform to those verification documents. My questions: Does delegate pattern fit better for unit testing than KVO? If KVO fits better, would you please suggest some sample codes?

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