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  • Repository Pattern Standardization of methods

    - by Nix
    All I am trying to find out the correct definition of the repository pattern. My original understanding was this (extremely dubmed down) Separate your Business Objects from your Data Objects Standardize access methods in data access layer. I have really seen 2 different implementations. Implementation 1 : public Interface IRepository<T>{ List<T> GetAll(); void Create(T p); void Update(T p); } public interface IProductRepository: IRepository<Product> { //Extension methods if needed List<Product> GetProductsByCustomerID(); } Implementation 2 : public interface IProductRepository { List<Product> GetAllProducts(); void CreateProduct(Product p); void UpdateProduct(Product p); List<Product> GetProductsByCustomerID(); } Notice the first is generic Get/Update/GetAll, etc, the second is more of what I would define "DAO" like. Both share an extraction from your data entities. Which I like, but i can do the same with a simple DAO. However the second piece standardize access operations I see value in, if you implement this enterprise wide people would easily know the set of access methods for your repository. Am I wrong to assume that the standardization of access to data is an integral piece of this pattern ? Rhino has a good article on implementation 1, and of course MS has a vague definition and an example of implementation 2 is here.

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  • iPhone OS: KVO: Why is my Observer only getting notified at applicationDidfinishLaunching

    - by nickthedude
    I am basically trying to implement an achievement tracking setup in my app. I have a managedObjectModel class called StatTracker to keep track of all sorts of stats and I want my Achievement tracking class to be notified when those stats change so I can check them against a value and see if the user has earned an achievement. I've tried to impliment KVO and I think I'm pretty close to making it happen but the problem I'm running into is this: So in the appDelegate i have an Ivar for my Achievement tracker class, I attach it as an observer to a property value of my statTracker core data entity in the applicationDidFinishLaunching method. I know its making the connection because I've been able to trigger a UIAlert in my AchievementTracker instance, and I've put several log statements that should be triggered whenever the value on the StatTracker's property changes. the log statement appears only once at the application launch. I'm wondering if I'm missing something in the whole object lifecycle scheme of things, I just don't understand why the observer stops getting notified of changes after the applicationDidFinishLaunching method has run. Does it have something to do with the scope of the AchievementTracker reference or more likely the reference to my core data StatTracker is going away once that method finishes up. I guess I'm not sure the right place to place these if that is the case. Would love some help. Here is the code where I add the observer in my appDidFinishLaunching method: [[CoreDataSingleton sharedCoreDataSingleton] incrementStatTrackerStat:@"timesLaunched"]; achievementsObserver = [[AchievementTracker alloc] init]; StatTracker *object = nil; object = [[[CoreDataSingleton sharedCoreDataSingleton] getStatTracker] objectAtIndex:0]; NSLog(@"%@",[object description]); [[CoreDataSingleton sharedCoreDataSingleton] addObserver:achievementsObserver toStat:@"refreshCount"]; here is the code in my core data singleton: -(void) addObserver:(id)observer toStat:(NSString *) statToObserve { NSLog(@"observer added"); NSArray *array = [[NSArray alloc] init]; array = [self getStatTracker]; [[array objectAtIndex:0] addObserver:observer forKeyPath:statToObserve options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld context:NULL]; } and my AchievementTracker: - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { NSLog(@"achievemnt hit"); //NSLog("%@", [change description]); if ([keyPath isEqual:@"refreshCount"] && ((NSInteger)[change valueForKey:@"NSKeyValueObservingOptionOld"] == 60) ) { NSLog(@"achievemnt hit inside"); UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"title" message:@"achievement unlocked" delegate:self cancelButtonTitle:@"cancel" otherButtonTitles:nil]; [alert show]; } }

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  • Creating Entity Framework objects with Unity for Unit of Work/Repository pattern

    - by TobyEvans
    Hi there, I'm trying to implement the Unit of Work/Repository pattern, as described here: http://blogs.msdn.com/adonet/archive/2009/06/16/using-repository-and-unit-of-work-patterns-with-entity-framework-4-0.aspx This requires each Repository to accept an IUnitOfWork implementation, eg an EF datacontext extended with a partial class to add an IUnitOfWork interface. I'm actually using .net 3.5, not 4.0. My basic Data Access constructor looks like this: public DataAccessLayer(IUnitOfWork unitOfWork, IRealtimeRepository realTimeRepository) { this.unitOfWork = unitOfWork; this.realTimeRepository = realTimeRepository; } So far, so good. What I'm trying to do is add Dependency Injection using the Unity Framework. Getting the EF data context to be created with Unity was an adventure, as it had trouble resolving the constructor - what I did in the end was to create another constructor in my partial class with a new overloaded constructor, and marked that with [InjectionConstructor] [InjectionConstructor] public communergyEntities(string connectionString, string containerName) :this() { (I know I need to pass the connection string to the base object, that can wait until once I've got all the objects initialising correctly) So, using this technique, I can happily resolve my entity framework object as an IUnitOfWork instance thus: using (IUnityContainer container = new UnityContainer()) { container.RegisterType<IUnitOfWork, communergyEntities>(); container.Configure<InjectedMembers>() .ConfigureInjectionFor<communergyEntities>( new InjectionConstructor("a", "b")) DataAccessLayer target = container.Resolve<DataAccessLayer>(); Great. What I need to do now is create the reference to the repository object for the DataAccessLayer - the DAL only needs to know the interface, so I'm guessing that I need to instantiate it as part of the Unity Resolve statement, passing it the appropriate IUnitOfWork interface. In the past, I would have just passed the Repository constructor the db connection string, and it would have gone away, created a local Entity Framework object and used that just for the lifetime of the Repository method. This is different, in that I create an Entity Framework instance as an IUnitOfWork implementation during the Unity Resolve statement, and it's that instance I need to pass into the constructor of the Repository - is that possible, and if so, how? I'm wondering if I could make the Repository a property and mark it as a Dependency, but that still wouldn't solve the problem of how to create the Repository with the IUnitOfWork object that the DAL is being Resolved with I'm not sure if I've understood this pattern correctly, and will happily take advice on the best way to implement it - Entity Framework is staying, but Unity can be swapped out if not the best approach. If I've got the whole thing upside down, please tell me thanks

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  • ASP.NET MVC ViewModel Pattern

    - by Omu
    EDIT: I made something much better to fill and read data from a view using ViewModels, called it ValueInjecter. http://valueinjecter.codeplex.com/documentation using the ViewModel to store the mapping logic was not such a good idea because there was repetition and SRP violation, but now with the ValueInjecter I have clean ViewModels and dry mapping code I made a ViewModel pattern for editing stuff in asp.net mvc this pattern is usefull when you have to make a form for editing an entity and you have to put on the form some dropdowns for the user to choose some values public class OrganisationViewModel { //paramterless constructor required, cuz we are gonna get an OrganisationViewModel object from the form in the post save method public OrganisationViewModel() : this(new Organisation()) {} public OrganisationViewModel(Organisation o) { Organisation = o; Country = new SelectList(LookupFacade.Country.GetAll(), "ID", "Description", CountryKey); } //that's the Type for whom i create the viewmodel public Organisation Organisation { get; set; } #region DropDowns //for each dropdown i have a int? Key that stores the selected value public IEnumerable<SelectListItem> Country { get; set; } public int? CountryKey { get { if (Organisation.Country != null) { return Organisation.Country.ID; } return null; } set { if (value.HasValue) { Organisation.Country = LookupFacade.Country.Get(value.Value); } } } #endregion } and that's how i use it public ViewResult Edit(int id) { var model = new OrganisationViewModel(organisationRepository.Get(id)); return View(model); } [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(OrganisationViewModel model) { organisationRepository.SaveOrUpdate(model.Organisation); return RedirectToAction("Index"); } and the markup <p> <label for="Name"> Name:</label> <%= Html.Hidden("Organisation.ID", Model.Organisation.ID)%> <%= Html.TextBox("Organisation.Name", Model.Organisation.Name)%> <%= Html.ValidationMessage("Organisation.Name", "*")%> </p> <p> ... <label for="CountryKey"> Country:</label> <%= Html.DropDownList("CountryKey", Model.Country, "please select") %> <%= Html.ValidationMessage("CountryKey", "*") %> </p> so tell me what you think about it

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  • Refactor Regex Pattern - Java

    - by UK
    Hello All, I have the following aaaa_bb_cc string to match and written a regex pattern like \\w{4}+\\_\\w{2}\\_\\w{2} and it works. Is there any simple regex which can do this same ?

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  • Pattern Matching with XSLT

    - by genesis11
    I'm trying to match a pattern into a string in XSLT/XPath using the matches function, as follows: <xsl:when test="matches('awesome','awe')"> ... </xsl:when> However, in both Firefox 3.5.9 and IE8, it doesn't show up. IE8 tells me that "'matches' is not a valid XSLT or XPath function." Is this due to XSLT 2.0 not being supported, and is there a way around this?

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  • java filenames filter pattern

    - by Sergey
    Hello, I need to implement File[] files = getFiles( String folderName, String ptrn ); Where ptrn is a command prompt style pattern like "*2010*.txt" I'm familar with FilenameFilter class, but can't implement public boolean accept(File dir, String filename) because String.matches() doesn't accept such patterns. Thanks!

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  • Java - is this an idiom or pattern, behavior classes with no state

    - by Berlin Brown
    I am trying to incorporate more functional programming idioms into my java development. One pattern that I like the most and avoids side effects is building classes that have behavior but they don't necessarily have any state. The behavior is locked into the methods but they only act on the parameters passed in. The code below is code I am trying to avoid: public class BadObject { private Map<String, String> data = new HashMap<String, String>(); public BadObject() { data.put("data", "data"); } /** * Act on the data class. But this is bad because we can't * rely on the integrity of the object's state. */ public void execute() { data.get("data").toString(); } } The code below is nothing special but I am acting on the parameters and state is contained within that class. We still may run into issues with this class but that is an issue with the method and the state of the data, we can address issues in the routine as opposed to not trusting the entire object. Is this some form of idiom? Is this similar to any pattern that you use? public class SemiStatefulOOP { /** * Private class implies that I can access the members of the <code>Data</code> class * within the <code>SemiStatefulOOP</code> class and I can also access * the getData method from some other class. * * @see Test1 * */ class Data { protected int counter = 0; public int getData() { return counter; } public String toString() { return Integer.toString(counter); } } /** * Act on the data class. */ public void execute(final Data data) { data.counter++; } /** * Act on the data class. */ public void updateStateWithCallToService(final Data data) { data.counter++; } /** * Similar to CLOS (Common Lisp Object System) make instance. */ public Data makeInstance() { return new Data(); } } // End of Class // Issues with the code above: I wanted to declare the Data class private, but then I can't really reference it outside of the class: I can't override the SemiStateful class and access the private members. Usage: final SemiStatefulOOP someObject = new SemiStatefulOOP(); final SemiStatefulOOP.Data data = someObject.makeInstance(); someObject.execute(data); someObject.updateStateWithCallToService(data);

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  • Is scala's cake pattern possible with parametrized components?

    - by Nicolas
    Parametrized components work well with the cake pattern as long as you are only interested in a unique component for each typed component's, example: trait AComponent[T] { val a:A[T] class A[T](implicit mf:Manifest[T]) { println(mf) } } class App extends AComponent[Int] { val a = new A[Int]() } new App Now my application requires me to inject an A[Int] and an A[String], obviously scala's type system doesn't allow me to extends AComponent twice. What is the common practice in this situation ?

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  • Command Design Pattern

    - by pchajer
    After reading command design pattern, I have a couple of question - Why we are creating concrete command and receiver object on client. Can't this initialization on invoker class? I think client should create invoker and pass it's request to invoker. Invoker should take care of all the stuff. By doing this, We have less dependency on client. The design of class diagram is totally different from actual design.

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  • MVC repository pattern design decision

    - by bradjive
    I have an asp .net MVC application and recently started implementing the repository pattern with a service validation layer, much like this. I've been creating one repository/service for each model that I create. Is this overkill? Instead, should I create one repository/service for each logical business area that provides CRUD for many different models? To me, it seems like I'm either cluttering the project tree with many files or cluttering a class with many methods. 6 one way half dozen the other. Can you think of any good arguments either way?

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  • Using a Generic Repository pattern with fluent nHibernate

    - by alex
    I'm currently developing a medium sized application, which will access 2 or more SQL databases, on different sites etc... I am considering using something similar to this: http://mikehadlow.blogspot.com/2008/03/using-irepository-pattern-with-linq-to.html However, I want to use fluent nHibernate, in place of Linq-to-SQL (and of course nHibernate.Linq) Is this viable? How would I go about configuring this? Where would my mapping definitions go etc...? This application will eventually have many facets - from a WebUI, WCF Library and Windows applications / services. Also, for example on a "product" table, would I create a "ProductManager" class, that has methods like: GetProduct, GetAllProducts etc... Any pointers are greatly received.

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  • Parametrized Strategy Pattern

    - by ott
    I have several Java classes which implement the strategy pattern. Each class has variable number parameters of different types: interface Strategy { public data execute(data); } class StrategyA implements Strategy { public data execute(data); } class StrategyB implements Strategy { public StrategyB(int paramA, int paramB); public data execute(data); } class StrategyB implements Strategy { public StrategyB(int paramA, String paramB, double paramC); public data execute(data); } Now I want that the user can enter the parameters in some kind of UI. The UI should be chosen at runtime, i.e. the strategies should be independent of it. The parameter dialog should not be monolithic and there should be the possibility to make it behave and look different for each strategy and UI (e.g. console or Swing). How would you solve this problem?

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  • myth about factory pattern

    - by leiz
    This has bothered me for awhile, and I have no clues if this is a myth. It seems that a factory pattern can ease the pain of adding a dependency for a class. For example, in a book, it has something like this Suppose that you have a class named Order. Initially it did not depend on anything. Therefore you didn't bother using a factory to create Order objects and you just used plain new to instantiate the objects. However, you now have a requirement that Order has to be created in association with a Customer. There are million places you need to change to add this extra parameter. If only you had de?ned a factory for the Order class, you would have met the new requirement without the same pain. How is this not same pain as adding an extra parameter to the constructor? I mean you would still need to provide an extra argument for the factory and that is also used by million places, right?

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  • C# ProgressBar design pattern

    - by MadSeb
    Hi, I'm working on a database upgrader application. The upgrader updates the schema of a database ( adds new columns, renames columns , adds new tables, new views to an existing database by executing SQL statements ). When a user wants to upgrade from version 1.0 to 2.0 , "Upgrader" objects are taken from an object factory and the "Execute" method of each "Upgrader" is called. The GUI of the application has a progress bar and each time an upgrader object performs a SQL statement the progress bar gets incremented. while (!version.Equal(CurrentVersion)) { IUpgrader myUpgrader = UpgraderFactory.GetUpgrader(version); myUpgrader.Execute(UpgradedFile,progressbar); version.Increment(); } My question is very simple : how should the upgrader object communicate with the progressbar. In the code above, the upgrader object is given direct access to the progressbar but I'm wondering if some better way of doing this or better design pattern exists. Regards, Seb

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  • makefile pattern rules: single wildcard, multiple instances in prerequisite

    - by johndashen
    Hi all, hopefully this is a basic question about make pattern rules: I want to use a wildcard more than once in a prerequisite for a rule, i.e. in my Makefile I have data/%P1.m: $(PROJHOME)/data/%/ISCAN/%P1.RAW @echo " Writing temporary matlab file for $*" # do something data/%P2.m: $(PROJHOME)/data/%/ISCAN/AGP2.RAW @echo " Writing temporary matlab file for $*" # do something In this example, I try to invoke make when the wildcard % is AG. Both files $(PROJHOME)/data/AG/ISCAN/AGP1.RAW and $(PROJHOME)/data/AG/ISCAN/AGP2.RAW exist. I attempt the following make commands and get this output: [jshen@iLab10 gender-diffs]$ make data/AGP1.m make: *** No rule to make target `data/AGP1.m'. Stop. [jshen@iLab10 gender-diffs]$ make data/AGP2.m Writing temporary matlab file for AG, part 2... [jshen@iLab10 gender-diffs]$ ls data/AG/ISCAN/AG* data/AG/ISCAN/AGP1.RAW data/AG/ISCAN/AGP2.RAW How can I implement multiple instances of the same wildcard in the first make rule?

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  • augment the factory pattern in java

    - by TP
    I am trying to use a factory pattern to create a QuestionTypeFactory where the instantiated classes will be like MultipleChoice, TrueFalseQuestion etc. The factory code looks something like this class QuestionFactory { public enum QuestionType { TrueFalse, MultipleChoice, Essay } public static Question createQuestion(QuestionType quesType) { switch (quesType) { case TrueFalse: return new TrueFalseQuestion(); case MultipleChoice: return new MultipleChoiceQuestion(); case Essay: return new EssayQuestion(); } throw new IllegalArgumentException("Not recognized."); } } This works ok for now. If I want to add another question type I will need to modify the factory class and I do not want to do that. How can I set it up so that each question class registers itself with the Factory so that when I add a new question type, I do not have to change the code for the factory? I am a bit new to java and am not sure how to do this.

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  • State pattern: Why doesn't the context class implement or inherit the State abstract interface/class

    - by Ricket
    I'm reading about the State pattern. I have only just begun, so of course I begin by reading the entire Wikipedia article on it. I noticed that both of the examples in the article have some base abstract class or Java interface for a generic State's methods/functions. Then there are some states which inherit from the base and implement those methods/functions in different ways. Then there's a Context class which has a private member of type State and which, at any time, can be equal to an instance of one of the implementations. That context class also implements the same methods, and passes them onto the current state instance, and then has an additional method to change the state (or depending on design I understand the change of state could be a reaction to one of the implemented methods). Why doesn't this context class specifically "extend" or "implement" the generic State base class/interface?

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  • C++ visitor pattern handling templated string types?

    - by Steve the Plant
    I'm trying to use the visitor pattern to serialize the contents of objects. However one snag I'm hitting is when I'm visiting strings. My strings are of a templated type, similar to STL's basic_string. So something like: basic_string<char_type, memory_allocator, other_possible_stuff> \\ many variations possible! Since I can have very many different templated string types, I can't go and add them to my visitor interface. It would be ridiculous. But I can't add templates to my VisitString method because C++ prevents using templates parameters in virtual methods. So what are my options to work around this?

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  • XSD string pattern independent of leading/trailing space

    - by AndiDog
    I have a XSD simple type that should match UUIDs: <simpleType name="UuidT"> <restriction base="string"> <pattern value="[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}" /> </restriction> </simpleType> It correctly matches the following content: <!-- valid --> <Uuid>12345678-1234-5678-9012-123456789012</Uuid> But it doesn't match content that contains excess whitespace: <!-- not valid --> <Uuid> 2de25a81-b117-4b2a-b910-50f0878884f7 </Uuid> Sure, I could add \s* to both sides of the regex, but isn't there a simpler solution in XSD?

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