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  • About Data Objects and DAO Design when using Hibernate

    - by X. Ma
    I'm hesitating between two designs of a database project using Hibernate. Design #1. (1) Create a general data provider interface, including a set of DAO interfaces and general data container classes. It hides the underneath implementation. A data provider implementation could access data in database, or an XML file, or a service, or something else. The user of a data provider does not to know about it. (2) Create a database library with Hibernate. This library implements the data provider interface in (1). The bad thing about Design #1 is that in order to hide the implementation details, I need to create two sets of data container classes. One in the general data provider interface - let's call them DPI-Objects, the other set is used in the database library, exclusively for entity/attribute mapping in Hibernate - let's call them H-Objects. In the DAO implementation, I need to read data from database to create H-Objects (via Hibernate) and then convert H-Objects into DPI-Objects. Design #2. Do not create a general data provider interface. Expose H-Objects directly to components that use the database lib. So the user of the database library needs to be aware of Hibernate. I like design #1 more, but I don't want to create two sets of data container classes. Is that the right way to hide H-Objects and other Hibernate implementation details from the user who uses the database-based data provider? Are there any drawbacks of Design #2? I will not implement other data provider in the new future, so should I just forget about the data provider interface and use Design #2? What do you think about this? Thanks for your time!

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  • WpfToolkit DataGrid does not work in Windows Phone 7

    - by Igor Zevaka
    I am trying to use WpfToolkit DataGrid in Windows Phone 7 project (Silverligt 4) and it's not working. Here is the XAML: <UserControl x:Class="SilverlightControls.Grid" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" xmlns:wtk="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" d:DesignHeight="480" d:DesignWidth="480"> <Grid x:Name="LayoutRoot" Background="#FF1F1F1F" Width="960"> <Grid x:Name="TitleGrid"> <TextBlock Text="{Binding Title}" Style="{StaticResource PhoneTextPageTitle2Style}"/> </Grid> <wtk:DataGrid> </wtk:DataGrid> </Grid> </UserControl> The project compiles fine but crashes at runtime trying to load this control. The best clue I got so far is from Visual Studio Designer. Once I add wtk:DataGrid to the control the visual designer does not load and below is the exception it displays. Could it be that WpfToolkit relies on PresentationFramework.dll and it's not available in SL4? System.Reflection.Adds.UnresolvedAssemblyException Type universe cannot resolve assembly: PresentationFramework, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35. at System.Reflection.Adds.AssemblyProxy.GetResolvedAssembly() at System.Reflection.Adds.AssemblyProxy.get_FullName() at Microsoft.Windows.Design.Metadata.ReflectionMetadataContext.PrepareAttributes(Reflectable`1 reflectableAssembly) at Microsoft.Windows.Design.Metadata.ReflectionMetadataContext.PrepareAttributes(Reflectable`1 reflectableType) at MS.Internal.Metadata.ClrType.GetAttributes[T](ReflectionMetadataContext context, IReflectable`1 member, ITypeMetadata attributeType, Boolean merge, AttributeMergeCache& cache) at MS.Internal.Metadata.ClrMember`1.GetLocalAttributes(ITypeMetadata attributeType) at MS.Internal.Design.Metadata.Xaml.XamlType.GetSpecialProperty(Int32 idx, PropertyIdentifier pid) at MS.Internal.Design.Metadata.Xaml.XamlType.get_ContentProperty() at Microsoft.Windows.Design.Metadata.Xaml.XamlExtensionImplementations.GetContentProperty(ITypeMetadata sourceType) at Microsoft.Windows.Design.Metadata.Xaml.XamlExtensions.GetContentProperty(ITypeMetadata source) at MS.Internal.Design.Metadata.ReflectionTypeNode.get_ContentProperty() at MS.Internal.Design.Markup.XmlElement.CalcChildWhitespaceImportant(XamlElement element) at MS.Internal.Design.Markup.XmlElement.ConvertChildrenToXaml(XamlElement result, PrefixScope scope, IParseContext context, IMarkupSourceProvider provider, Boolean childrenAsString) at MS.Internal.Design.Markup.XmlElement.ConvertToXaml(XamlElement parent, PrefixScope parentScope, IParseContext context, IMarkupSourceProvider provider) at MS.Internal.Design.Markup.XmlElement.ConvertChildrenToXaml(XamlElement result, PrefixScope scope, IParseContext context, IMarkupSourceProvider provider, Boolean childrenAsString) at MS.Internal.Design.Markup.XmlElement.ConvertToXaml(XamlElement parent, PrefixScope parentScope, IParseContext context, IMarkupSourceProvider provider) at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlSourceDocument.ParseElementFromSkeleton(XamlParseContext context, SkeletonNode node, XamlElement parent, Boolean fullElement) at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlSourceDocument.UpdateSkeleton(IDamageListener listener) at Microsoft.Windows.Design.DocumentModel.Trees.MarkupDocumentTreeManager.Update() at Microsoft.Windows.Design.DocumentModel.MarkupProducer.Update() at Microsoft.Windows.Design.DocumentModel.MarkupProducer.HandleMessage(DocumentTreeCoordinator sender, MessageKey key, MessageArguments args) at Microsoft.Windows.Design.DocumentModel.MarkupProducer.Microsoft.Windows.Design.DocumentModel.IDocumentTreeConsumer.HandleMessage(DocumentTreeCoordinator sender, MessageKey key, MessageArguments args) at Microsoft.Windows.Design.DocumentModel.DocumentTreeCoordinator.SendMessage[T](MessageKey`1 key, T args, Boolean isPrivateMessage) at Microsoft.Windows.Design.DocumentModel.DocumentTreeCoordinator.QueuedMessage`1.Microsoft.Windows.Design.DocumentModel.IQueuedMessage.Invoke() at Microsoft.Windows.Design.DocumentModel.DocumentTreeCoordinator.ProcessQueuedMessages(Object state) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs) at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)

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  • Do I need to use any other attributes other than CssClassProperty to enabled design-time support?

    - by keith
    Hi, I'm trying to provide the same design-time support that the CssClass provides on some custom properties of a server control. The documentation suggests that decorating the property with the CssClassProperty is all that's required. [CssClassProperty] public string SomeOtherCssClass{get;set;} This has no effect, in vs2008 or vs2010. I've looked at the WebControl class using reflector and implemented all the attributes, and every combination thereof, to my property and still no class dropdown. Some blog posts suggest that the use of the Editor attribute but a) there's not mention of it in the documentation and b) none of editors which are remotely related to css classes have any effect either. Am I missing something to enable this feature? Thanks in advance, Keith.

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  • is it wasteful/bad design to use a vector/list where in most instances it will only have one element

    - by lucid
    is it wasteful/bad design to use a vector/list where in most instances it will only have one element? example: class dragon { ArrayList<head> = new ArrayList<head> Heads; tail Tail = new tail(); body Body = new body(); dragon() { theHead=new head(); Heads.add(theHead); } void nod() { for (int i=0;i<Heads.size();i++) { heads.get(i).GoUpAndDown(); } } } class firedragon extends dragon { } class icedragon extends dragon { } class lightningdragon extends dragon { } // 10 other one-headed dragon declarations here class hydra extends dragon { hydra() { anotherHead=new head(); for (int i=0;i<2;i++) { Heads.add(anotherHead); } } } class superhydra extends dragon { superhydra() { anotherHead=new head(); for (int i=0;i<4;i++) { Heads.add(anotherHead); } } }

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  • can we have one attribute with multiple values in an eav design?

    - by Shekhar
    i am doing a database design using EAV. I am facing an issue when i try to model an entity with attribute having multiple values? For example Entity id | name | description 1 | configuration1 | configuration1 Attribute id | entityId | name | type 1 | 1 |att1 | string 2 | 1 |att2 | int 3 |1 | att3 | List (How will i model this?) Value id | attributeId | value 1 | 1 | a 2 | 2 | 1 3 | 3 | b 4 | 3 | c 5 | 3 |d Is this the correct way to handle list of values? Please provide any helpful link to model this? Thanks Shekhar

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  • Singleton class design in C#, are these two classes equivalent?

    - by Oskar
    I was reading up on singleton class design in C# on this great resource and decided to go with alternative 4: public sealed class Singleton1 { static readonly Singleton1 _instance = new Singleton1(); static Singleton1() { } Singleton1() { } public static Singleton1 Instance { get { return _instance; } } } Now I wonder if this can be rewritten using auto properties like this? public sealed class Singleton2 { static Singleton2() { Instance = new Singleton2(); } Singleton2() { } public static Singleton2 Instance { get; private set; } } If its only a matter of readability I definitely prefer the second version, but I want to get it right.

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  • How can I avoid properties being reset at design-time in tightly bound user controls?

    - by David Anderson
    I have UserControl 'A' with a label, and this property: /// <summary> /// Gets or Sets the text of the control /// </summary> [ Browsable(true), EditorBrowsable(EditorBrowsableState.Always), Category("Appearance") ] public override string Text { get { return uxLabel.Text; } set { uxLabel.Text = value; } } I then have UserControl 'B' which has UserControl 'A' on it, and I set the Text Property to "My Example Label" in the designer. Then, I have my MainForm, which has UserControl 'B' on it. Each time I do a build or run, the Text property of UserControl 'A' is reset to its default value. I suppose this is because since I am doing a rebuild, it rebuilds both UserControl 'A' and 'B', thus causing the problem. How can I go about a better approach to design pattern to avoid this type of behavior when working with tightly bound controls and forms in a application?

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  • how can I design a good architechture for a Transaction Processing System?

    - by ghedas
    I have a project that must design an architecture for it. This project is a something like a Transaction Processing system and I need to know something like this: when and where I must use synchronous and asynchronous relations between its components? If always I use synchronous relations, the amount of messages maybe become exceeded and makes problem for TP system, and on the other hand synchronous relations make lots of delay, I think a mixture of them is required! If other parameters required to considering please help me! the most nonfunctional requirements of this project are performance and availability of it. I need useful materials and suggestions for it.

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  • Is using a FSM a good design for general text parsing?

    - by eSKay
    I am reading a file that is filled with hex numbers. I have to identify a particular pattern, say "aaad" (without quotes) from it. Every time I see the pattern, I generate some data to some other file. This would be a very common case in designing programs - parsing and looking for a particular pattern. I have designed it as a Finite State Machine and structured structured it in C using switch-case to change states. This was the first implementation that occured to me. DESIGN: Are there some better designs possible? IMPLEMENTATION: Do you see some problems with using a switch case as I mentioned?

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  • Stream classes ... design, pattern for creating views over streams

    - by ToxicAvenger
    A question regarding the design of stream classes - I need a pattern to create independent views over a single stream instance (in my case for reading). A view would be a consecutive part of the stream. The problem I have with the stream classes is that the state (reading or writing) is coupled with the underlying data/storage. So if I need to partition a stream into different segments (whether segments overlap or not doesn't matter), I cannot easily create views over the stream, the views would store start and end position. Because reading from a view - which would translate to reading from the underlying stream adjusted based on the start/end positions - would change the state of the underlying stream instance. So what I could do is take a read on a view instance, adjust the Position of the stream, read the chunks I need. But I cannot do that concurrently. Why is it designed in such a way, and what kind of pattern could I implement to create independet views over a single stream instance which would allow to read/write independently (and concurrently)?

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  • ASP.NET (AJAX) UI Design Tools for Artistically Challenged?

    - by davemackey
    I'm building an application but I'm artistically challenged and I'd rather not spend my time writing widgets (e.g. ability to collapse/expand/close/drag-drop) if there is already controls available. I've worked with the Microsoft AJAX Control Toolkit - but these tools still require a lot of work to get a working widget (which in my case, won't look too pretty). The CollapsiblePanel is pretty nice - but then you have to program in the minimize button, close button, maximize button, etc. Looking for suggestions that will help me design better UI faster...

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  • What problems do you find with this view on domain-driven design?

    - by Bozho
    I just wrote a long (and messy) blogpost about my view on domain-driven design at present day, with frameworks like spring and hibernate massively in use. I'd ask you to spot any problems with my views on the matter - why this won't work, why it isn't giving the benefits of DDD, why it is not a good idea in general. The blogpost is here (I don't think I need to copy-paste it on SO - if you think I should, tell me). I know the question is subjective, but it is aimed at gathering the most predominant opinions. (I'm tagging Java, since the frameworks discussed are Java frameworks)

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  • Is there a design pattern for injecting methods into a class?

    - by glenn I.
    I have a set of classes that work together (I'm coding in javascript). There is one parent class and a number of child classes that are instantiated by the parent class. I have a number of clients of these classes that each need to add on one more methods to the parent or child classes. Rather than having each client inherit from these classes, which is doable but messy because of the child classes, I am having these clients pass functions into the parent class when they instantiate the main class. The main class creates the methods dynamically and the clients can call the methods like they were there all along. My questions are: is this a sensible thing to do? what would the design pattern be for what I am doing?

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  • How can I handle multiple views of a data object? Which design pattern is acceptable?

    - by tranquil.byte
    I have a person object. class Person { private $name; ... } I need to be able to change how they are displayed on the front-end ( visitors have control ). They can choose list view, grid view, photo view for example. class PersonDisplay { public function displayList() { // Query database // Output html to display in list mode } public function displayPhoto() { // Query database // Output html to display in photo mode } } Is this an acceptable way to handle the presentation of the items on the front-end or is there a specific design pattern I should be researching to help me with this task? Does anyone have any suggestions or ideas where this could go wrong or if this could potentially make maintenance a nightmare? The Person object was just an example very similiar to what I am using.

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  • What is the best design for these data base tables?

    - by Mohammed Jamal
    I need to find the best solution to make the DB Normalized with large amount of data expected. My site has a Table Tags (contain key word,id) and also 4 types of data related to this tags table like(articles,resources,jobs,...). The big question is:- for the relation with tags what best solution for optimazaion & query speed? make a table for each relation like: table articlesToTags(ArticleID,TagID) table jobsToTags(jobid,tagid) etc. or put it all in one table like table tagsrelation(tagid,itemid,itemtype) I need your help. Please provide me with articles to help me in this design consider that in future the site can conation new section relate to tag Thanks

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  • How would you go to "design" a cart within a Zend Framework project?

    - by ÉricP
    Hi, I know ZF well, and a little bit of Magento, but I'm new to E-commerce, and I'm sure there are best practice to follow when designing a cart model. How would go to design a cart? I though of two models, Model_Cart and Model_Cart_Item used in conjonction with Zend_Session to store the cart in session. What are your feedbacks? How would you go to do that? What should I know about writing a cart system? Note that I need a simple system, I even don't need to work with quantity

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  • What are you using for Web UI/layout design?

    - by brendan
    What are folks out there using for web/ui design? For the most part we use PowerPoint at my company. The UI folks will mock up a screen in PowerPoint and we (the development group) will take it from there. So, for a side gig of mine I decided to do some mock ups to show the client prior to dev and I'm quickly feeling that PowerPoint is not the right tool for this. What are you using for this type of stuff - some other software? pen/paper?

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  • Ideas for using R to create a T-shirt design (for useR 2010) ?

    - by Tal Galili
    There is now a competition for creating a T-shirt design for useR2010. Someone proposed the idea to use R for creating the T-shirt image. Which leads me to my questions: What type of images do you think might be fitting for this? How would you suggest to use R to create the images ? Would anyone here want to have a go at it? (p.s: I understand this is not a pure "programming" question. Yet it involves R programming, the understanding of R aesthetics, and some caring for the R community. I also understand I am at the risk of annoying people here with this question, so in case that happens - I deeply apologies! My only justification is that I am acting in good faith and in the purpose of having nice things for R users to enjoy, while learning something in the process) Related thread I once opened: http://stackoverflow.com/questions/2162131/how-can-i-learn-to-create-beautiful-infographics-with-connection-to-my-r-knowled

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  • c# class design - what can I use instead of "static abstract"?

    - by Ryan
    I want to do the following public abstract class MyAbstractClass { public static abstract int MagicId { get; } public static void DoSomeMagic() { // Need to get the MagicId value defined in the concrete implementation } } public class MyConcreteClass : MyAbstractClass { public static override int MagicId { get { return 123; } } } However I can't because you can't have static abstract members. I understand why I can't do this - any recommendations for a design that will achieve much the same result? (For clarity - what I am trying to do is provide a library with an abstract base class but the concrete versions MUST implement a few properties/methods themselves and yes, there are good reasons for keeping it static.)

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  • How can Domain driven design be combined with aspect oriented programming?

    - by anthares
    I'm doing research and one point I want to cover is "What is the relationship between Domain-driven Design and Aspect oriented programming?" I know that a main principle in DDD is separation of concerns and I understand that. What I'm not really certain is, whether aspects in AOP acts like "sub domains" in our domain in DDD. Are these two concepts, basically the same thing. I mean, If I develop an application following AOP and DDD, at the end of the day will it be true that "a sub domain" == "an aspect". I will also appreciate any other opinions what is the common between AOP and DDD.

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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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  • Question on the implementation of my Entity System

    - by miguel.martin
    I am currently creating an Entity System, in C++, it is almost completed (I have all the code there, I just have to add a few things and test it). The only thing is, I can't figure out how to implement some features. This Entity System is based off a bit from the Artemis framework, however it is different. I'm not sure if I'll be able to type this out the way my head processing it. I'm going to basically ask whether I should do something over something else. Okay, now I'll give a little detail on my Entity System itself. Here are the basic classes that my Entity System uses to actually work: Entity - An Id (and some methods to add/remove/get/etc Components) Component - An empty abstract class ComponentManager - Manages ALL components for ALL entities within a Scene EntitySystem - Processes entities with specific components Aspect - The class that is used to help determine what Components an Entity must contain so a specific EntitySystem can process it EntitySystemManager - Manages all EntitySystems within a Scene EntityManager - Manages entities (i.e. holds all Entities, used to determine whether an Entity has been changed, enables/disables them, etc.) EntityFactory - Creates (and destroys) entities and assigns an ID to them Scene - Contains an EntityManager, EntityFactory, EntitySystemManager and ComponentManager. Has functions to update and initialise the scene. Now in order for an EntitySystem to efficiently know when to check if an Entity is valid for processing (so I can add it to a specific EntitySystem), it must recieve a message from the EntityManager (after a call of activate(Entity& e)). Similarly the EntityManager must know when an Entity is destroyed from the EntityFactory in the Scene, and also the ComponentManager must know when an Entity is created AND destroyed. I do have a Listener/Observer pattern implemented at the moment, but with this pattern I may remove a Listener (which is this case is dependent on the method being called). I mainly have this implemented for specific things related to a game, i.e. Teams, Tagging of entities, etc. So... I was thinking maybe I should call a private method (using friend classes) to send out when an Entity has been activated, deleted, etc. i.e. taken from my EntityFactory void EntityFactory::killEntity(Entity& e) { // if the entity doesn't exsist in the entity manager within the scene if(!getScene()->getEntityManager().doesExsist(e)) { return; // go back to the caller! (should throw an exception or something..) } // tell the ComponentManager and the EntityManager that we killed an Entity getScene()->getComponentManager().doOnEntityWillDie(e); getScene()->getEntityManager().doOnEntityWillDie(e); // notify the listners for(Mouth::iterator i = getMouth().begin(); i != getMouth().end(); ++i) { (*i)->onEntityWillDie(*this, e); } _idPool.addId(e.getId()); // add the ID to the pool delete &e; // delete the entity } As you can see on the lines where I am telling the ComponentManager and the EntityManager that an Entity will die, I am calling a method to make sure it handles it appropriately. Now I realise I could do this without calling it explicitly, with the help of that for loop notifying all listener objects connected to the EntityFactory's Mouth (an object used to tell listeners that there's an event), however is this a good idea (good design, or what)? I've gone over the PROS and CONS, I just can't decide what I want to do. Calling Explicitly: PROS Faster? Since these functions are explicitly called, they can't be "removed" CONS Not flexible Bad design? (friend functions) Calling through Listener objects (i.e. ComponentManager/EntityManager inherits from a EntityFactoryListener) PROS More Flexible? Better Design? CONS Slower? (virtual functions) Listeners can be removed, i.e. may be removed and not get called again during the program, which could cause in a crash. P.S. If you wish to view my current source code, I am hosting it on BitBucket.

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  • In hindsight, is basing XAML on XML a mistake or a good approach?

    - by romkyns
    XAML is essentially a subset of XML. One of the main benefits of basing XAML on XML is said to be that it can be parsed with existing tools. And it can, to a large degree, although the (syntactically non-trivial) attribute values will stay in text form and require further parsing. There are two major alternatives to describing a GUI in an XML-derived language. One is to do what WinForms did, and describe it in real code. There are numerous problems with this, though it’s not completely advantage-free (a question to compare XAML to this approach). The other major alternative is to design a completely new syntax specifically tailored for the task at hand. This is generally known as a domain-specific language. So, in hindsight, and as a lesson for the future generations, was it a good idea to base XAML on XML, or would it have been better as a custom-designed domain-specific language? If we were designing an even better UI framework, should we pick XML or a custom DSL? Since it’s much easier to think positively about the status quo, especially one that is quite liked by the community, I’ll give some example reasons for why building on top of XML might be considered a mistake. Basing a language off XML has one thing going for it: it’s much easier to parse (the core parser is already available), requires much, much less design work, and alternative parsers are also much easier to write for 3rd party developers. But the resulting language can be unsatisfying in various ways. It is rather verbose. If you change the type of something, you need to change it in the closing tag. It has very poor support for comments; it’s impossible to comment out an attribute. There are limitations placed on the content of attributes by XML. The markup extensions have to be built "on top" of the XML syntax, not integrated deeply and nicely into it. And, my personal favourite, if you set something via an attribute, you use completely different syntax than if you set the exact same thing as a content property. It’s also said that since everyone knows XML, XAML requires less learning. Strictly speaking this is true, but learning the syntax is a tiny fraction of the time spent learning a new UI framework; it’s the framework’s concepts that make the curve steep. Besides, the idiosyncracies of an XML-based language might actually add to the "needs learning" basket. Are these disadvantages outweighted by the ease of parsing? Should the next cool framework continue the tradition, or invest the time to design an awesome DSL that can’t be parsed by existing tools and whose syntax needs to be learned by everyone? P.S. Not everyone confuses XAML and WPF, but some do. XAML is the XML-like thing. WPF is the framework with support for bindings, theming, hardware acceleration and a whole lot of other cool stuff.

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