How can I implement generics in this program so I do not have to cast to String in this line: String d = (String) h.get ("Dave"); import java.util.*; public class TestHashTable { public static void main (String[] argv) { Hashtable h = new Hashtable (); // Insert a string and a key. h.put ("Ali", "Anorexic Ali")...
I have the following method that takes in a details object, validates it, converts it to a request and enqueues it. Everything is fine apart from the validate request which I am having trouble with. Basically, there is different validation logic for each different details object. I know from the generic constraint that the details object...
I have been working on Google AdWords and came across this code adwords-api-6.4.0, com.google.api.adwords.lib.AdWordsUser public <T extends java.rmi.Remote> T getService(AdWordsService service) throws ServiceException { try { return (T) AdWordsServiceFactory.generateSerivceStub(service, this, service.getEndpointSe...
I have a method that checks if a type is generic and then checks if the GenericTypeDefinition is of IEnumerable<>. static Type GetEnumerableType(Type type) { if(type.IsGenericType) { var genericTypeDefinition = type.GetGenericTypeDefinition(); if (genericTypeDefinition == typeof(IEnumerable<>)) { ...
My obviously wrong understanding of Java Generics was up to now, that Type Erasure removes all type information such that there is nothing left at all at runtime. Recently i stumbled upon a code fragment where i had to ask myself: How the hack does this work? Simplified it presents as import java.lang.reflect.ParameterizedType; import...
I have recently been trying to learn more about the Entity Framework technologies from Microsoft. I have found a situation which I am not sure if it is possible (or correct) to solve using EF. I have lots of entities that can be referred to by lots of different names. For example, a persons occupation maybe described as "Coder", "Progra...
What is the better way to reuse implementation: inheritance or generics? The model is following: Script has Steps, Steps have Elements. Tree structure is double linked, i.e. Steps know their Script and Elements now their Step. Now, there are 2 types of Scripts: Templates and Runs, where a Run is created at first as a copy of the Templ...
I am creating a custom generic class: class Widget< T1, T2> { ... public bool Bar( T1 type1 ) { ... } public bool Bar( T2 type2 ) { ... } ... } The following lines, of course, creates an ambiguous call compile error: Widget<int, int> Foo = new Widget<int, int>(); ... Foo.Bar(5); ... I...
I fail to remove duplicates from my List. What am I doing wrong? Dim Contacts As New List(Of Person) ... ' remove duplicates ' Contacts = Contacts.Distinct(New PersonEqualityComparer).ToList my equality comparer: Public Class PersonEqualityComparer Implements IEqualityComparer(Of Person) Public Function Equals1(ByVal x As ...
Examine the code below public abstract class ClassA<ClassBType extends ClassB<ClassCType>,ClassCType extends ClassC> { public void method(ClassBType type) { type.myClassA = this; //Error. Type mismatch: cannot convert from TestGameMain.ClassA<ClassBType,ClassCType> to TestGameMain.ClassA<TestGameMain.ClassB<ClassCType>,Cla...
I am trying to determine if an object x is a list. It may be a list of any type and with any generic parameter. If it is, then I want to iterate over it if it is. This is the best I could come up with, but it fails due to a compilation error if(x is List){ foreach(Object o in (List)x){ ; } } How can I do this? ...
If 'value' is an incoming generic dictionary whose types are unknown/don't matter, how do I take its entries and put them into a target dictionary of type IDictionary<object, object> ? if(type == typeof(IDictionary<,>)) { // this doesn't compile // value is passed into the method as object and must be cast IDictionar...
I understand that I can't extend static classes in C#, I don't really understand the reason why, but I do understand that it can't be done. So, with that in mind, here is what I wanted to achieve: public static class GenericXmlSerialisationExtender { public static void WriteToXML<T>(this T targetObject, string fileName) { ...
I saw in a projekt many interfaces which just wrapped a generic class. An example: public interface IAssertionViewModelMapper : IMapper<Assertion, AssertionViewModel> {} public interface ISearchPageViewModelMapper : IMapper<IList<Tag>, SearchPageViewModel> {} Could someone explain why they did this ? I mean I can just straight impl...
What is the easiest way to do this? The results should be: 1: one 2: two 3: 4: 5: five Code: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TestLines8833 { class Program { static void Main(string[] args) { List<string> lines = new List<string>(); ...
Somebody help me with these generics! If you have an overloaded method with different types which can be an argument, can one write a generic method which at runtime call the right one? (Sorry if my java-nology is poor, if so) Example: public interface CoolInterface { setOverloadedValue(String o); setOverloadedValue(Integer o);...
I need to often convert a "string block" (a string containing return characters, e.g. from a file or a TextBox) into List<string>. What is a more elegant way of doing it than the ConvertBlockToLines method below? using System; using System.Collections.Generic; using System.Linq; namespace TestConvert9922 { class Program { ...
I want to be able to write extension methods so that I can say: lines.ForceSpaceGroupsToBeTabs(); instead of: lines = lines.ForceSpaceGroupsToBeTabs(); However, the following code currently outputs: ....one ........two instead of: Tone TTtwo What do I have to change in the following code to make it output: Tone TTtwo (not...
I use a Height for all the Foos members. Like this public class Foo<T> { public static int FoosHeight; } public partial class Form1 : Form { public Form1() { InitializeComponent(); Foo<???>.FoosHeight = 50; // DO I Set "object" here? } } The same situation is in VB.NET. ...
I have a generic business object collection class which contains some business objects: public abstract class BusinessObjectCollection<T> : ICollection<T> where T : BusinessObject I want to write a method on my Collection class that returns the type T and a method that returns a newly-instantiated object of type T. In C++, thi...