Hi all, I've got a problem with generic classes in java. I've got this class: public abstract class MyMotherClass<C extends AbstractItem> { private C item; public void setItem(C item) { this.item = item; } public C getItem() { return item; } } An implementation of this class can be: public...
I have a foreach loop reading a list of objects of one type and producing a list of objects of a different type. I was told that a lambda expression can achieve the same result. var origList = List<OrigType>(); // assume populated var targetList = List<TargetType>(); foreach(OrigType a in origList) { targetList.Add(new TargetType(...
I am trying to learn Java generics. I am not clear when you will use <T extends Foo> and when you will use <T super Foo>. What do each one of these things mean about T? Lets say I have <T extends Comparable> and <T super Comparable>, what do each of these mean? I've read several tutorials at sun.com but I'm still lost. Can somebody illu...
I'm using the Microsoft.Data.Entity.CTP (in the Entity Framework CTP) under the .NET 4 framework to create the EDMX metadata from my C# classes to create a database schema. I setup a simple model as such: public class AModelContainer : ObjectContext { public IObjectSet<RegularClass> RegularClasses { get { return CreateObje...
I am working on a generic game engine for simple board games and such. I am defining interfaces that I will require each game to implement I have classes like IGame, IGameState, IBoardEvaluator, and IMove. I have methods like IGame.PerformMove(IMove move), that I would like to restrict. If I am playing tic-tac-toe I would like to enforc...
I want to check if a given Class is assignable to a java.util.Collection, and if so create a new instance of it. I tried the following: Class<?> clazz = ... // I got this from somewhere if (!clazz.isInterface() && java.util.Collection.class.isAssignableFrom(clazz)) { java.util.Collection<?> collection = clazz.newInstance(); } ...
i want to write a generic stored procedure in oracle .For example i want to take table name as input and then do maipulations on it. I want to learn some sample generic codes and the basica of writing generic stored procedures in oracle. Can any one provie code snippets/ links to websites or other material for this? ...
i want to create instance of any class by generic way. is that possible?i know ,this is madly but this is only a question waits the its answer. i tried this but doesnt work. public class blabla { public void bla(); } public class Foo<T> { Dictionary<string, Func<object>> factory; public Foo() { fac...
Does .net CLR typecast the objects to the ones mentioned in the collection declaration? If i declare a List<string> lststrs= new List<string>(); lststrs.add("ssdfsf"); does .net typecasts this object while adding and retriving????? Well i think the question itself was not clearly understood by everyone.Let me elaborate. In java ther...
Currently I'm working on a service interface which retrieves domain objects based on a primary key. However I get the feeling I'm not efficiently using generics. Base domain objects look as follows: public interface DomainObject<PK extends Serializable> extends Serializable { PK getID(); } My service interface looks as follows: ...
Hello these, This does not compile, any suggestion appreciated. ... List<Object> list = getList(); return (List<Customer>) list; Compiler says: cannot cast List<Object> to List<Customer> ...
I want to write a PLSQL stored procedure that accepts a table name as argument. This table is source table. Now inside my procedure i want to manipulate the fields of that table. EX: I want to insert the records of this source table into another target table whose name is XYZ_<source table name>. The column names for source and targ...
We have: class A{} class B extends A{} class C extends B{} class D extends C{} we can define Lists like: List<? super B> lsb1 = new ArrayList<Object>(); //List<? super B> lsb2 = new ArrayList<Integer>();//Integer, we expect this List<? super B> lsb3 = new ArrayList<A>(); List<? super B> lsb4 = new ArrayList<B>(); //List<? super B...
I've got a custom class, which derives from UserControl. The code: public partial class Gallery<T> : UserControl where T : class, IElement, new() This classworks like it's supposed to work. But, when I try to enter design mode of the form which contains these Gallery classes, it gives me errors: Could not find type 'PresentrBu...
In my CMS I have a load of modules which allow me to do some clever item listing stuff. I am trying to use them to pull out a list of their child objects via reflection, but am getting stuck with the level of generics involved. I have got as far as this method: var myList = moduleObj.GetType().GetMethod("ChildItems").Invoke(moduleObj, ...
i have a method that returns a map defined as: public Map<String, ?> getData(); the actual implementation of this method is not clear to me, but: when i try to do: obj.getData().put("key","value") I get following compile time error message: The method put(String, capture#9-of ?) in the type Map is not applicable for the ar...
So I have an object, lets say Item<U>. I want to create a(n) (I)List<T> containing a collection of these items. The problem that I am running into is that the collection of Item<U> can have any number of different types for U in them. What I can not figure out is the signature to use for the IList. I tryed IList<Item<T>>, but because...
I have a class that I fill from the database: public class Option<T> { public T Value { get; set; } public T DefaultValue { get; set; } public List<T> AvailableValues { get; set; } } I want to have a collection of them: List<Option<T>> list = new List<Option<T>>(); Option<bool> TestBool = new Option<bool>(); TestBool.Value = tr...
Hello, Im developing some wpf app. Basically i have two types of windows: search windows and insert/edit windows. When i developed win forms apps, i used a trick, called MdiParent. In that way i had ability to put my caled search type windows in a "stack". In orher words if i called 5 different search windows from meniu, they apeared in ...
I have this Player class which implements the Comparable interface. Then I have an ArrayList of Players. I'm trying to use binarySearch() on the list of Players to find one Player, but Java is giving me a "cannot find symbol: method binarySearch(java.util.ArrayList< Player>,Player)". This the Player class: class Player implements Compa...