toString() a generic type in Java
How can I print the type of a generic java type? Reflection? Any tricks? public class Foo<K> { private K element; @Override public String toString() { return "Type: " + K; } } ...
generics
what is the best way to have a Generic Comparer
I have a lot of comparer classes where the class being compared is simply checking the name property of the object and doing a string compare. For example: public class ExerciseSorter : IComparer<Exercise> { public int Compare(Exercise x, Exercise y) { return String.Compare(x.Name, y.Name); } } public class CarSort...
Delphi: RTTI and TObjectList<TObject>
Based on one answer to an earlier post, I'm investigating the possibility of the following design TChildClass = class(TObject) private FField1: string; FField2: string; end; TMyClass = class(TObject) private FField1: TChildClass; FField2: TObjectList<TChildClass>; end; Now, in the real world, TMyClass will have 10 differe...
Dynamically Run IQueryable Method
Hi! I'm trying to run the Count() function of a Linq statement in an overriden Gridview function. Basically, I want to be able to assign a linq query to a gridview, and on the OnDataBound(e) event in my new extended gridview have it retrieve the count, using the IQueryable. So, I need to dynamically cast the GridView.DataSource to my L...
Generic type in generic collection
I have generic type that looks like: public class GenericClass<T, U> where T : IComparable<T> { // Class definition here } I then have a collection of these instances. What is the cleanest way to pass through the type constraints? public class GenericCollection<V> where V : GenericClass<T, U> // This won't compile { private...
Auto convert java source to use generic rather than raw types
Is there a way/tool to auto convert Java source code from using raw types to using generic types? I have some legacy code with 677 references to raw types: ArrayList 47 Vector 420 Hashtable 61 Enumeration 64 Class 7 Iterator 78 TOTAL 677 Now I could manually look through the code to infer the generic types and...
Generics and anonymous type
I understood,normally generics is for compile time safe and allow us to keep strongly typed collection.Then how do generic allow us to store anonymous types like List<object> TestList = new List<object>(); TestList.Add(new { id = 7, Name = "JonSkeet" }); TestList.Add(new { id = 11, Name = "Marc Gravell" }); TestList.Add(new { id = 31, N...
FluentNHibernate Overrides: UseOverridesFromAssemblyOf non-generic version
Hi, I have a repository class that inherits from a generic implementation: public namespace RepositoryImplementation { public class PersonRepository : Web.Generics.GenericNHibernateRepository<Person> } The generic repository implementation uses Fluent NHibernate conventions. They're working fine. One of those conventions is that ...
What is the difference between a generic type and a generic type definition?
I'm Studying up on .net reflection and am having a hard time figuring out the difference. From what I understand, List<T> is a generic type definition. Does that mean that to .net reflection T is the generic type? Specifically, I guess I'm looking for more background on the Type.IsGenericType and Type.IsGenericTypeDefinition functions...
Dynamic field type handling
I have to do an export from DB to CSV. (.NET 2) field; fileld; field... etc Have 3 types of fields: Alpha, Numeric and Bool respresented as "alphaValue",intValue and True/False. I try to encapsulate this in a fields collection, in order to export if alpha then set "", if Bool=>True/False if numeric let as is. and try to build a CsvF...
Insert into a generic dictionary with possibility of duplicate keys?
Is there any reason to favor one of these approaches over the other when inserting into a generic dictionary with the possibility of a key conflict? I'm building an in-memory version of a static collection so in the case of a conflict it doesn't matter whether the old or new value is used. If Not mySettings.ContainsKey(key) Then myS...
Creating circular generic references
I am writing an application to do some distributed calculations in a peer to peer network. In defining the network I have two class the P2PNetwork and P2PClient. I want these to be generic and so have the definitions of: P2PNetwork<T extends P2PClient<? extends P2PNetwork<T>>> P2PClient<T extends P2PNetwork<? extends T>> with P2PClie...
Generics : List<? extends Animal> is same as List<Animal>?
Hi, I am just trying to understand the extends keyword in Java Generics. List<? extends Animal> means we can stuff any object in the List which IS A Animal then won't the following also mean the same thing: List<Animal> Can someone help me know the difference between the above two? To me extends just sound redundant here. Thanks! ...
Is there a way to achieve covariance of generic types in C# 3.0?
This has been introduced in C# 4.0, but is there a way to achieve this in c# 3.0? For e.g., consider the following code: class Base { } class Derived1 : Base { } class Derived2 : Base { } class User<T> where T : Base { } class User1 : User<Derived1> { } Now, I would like to have a list of User<T>, in which I can store User<Derive...
Will the "generified" version of JTree (TreeModel, TreeNode, ...) be in JDK7?
I found out recently that JList (finally!) was "generified" in JDK7. Why JTree and related classes/interfaces are not changed the same? It would be a huge improvement. Casting Object is going on one's nerves. NOTE: The javadoc had not yet been updated, see here and here. ...
How do I get the type name of a generic type argument?
If I have a method signature like public string myMethod<T>( ... ) How can I, inside the method, get the name of the type that was given as type argument? I'd like to do something similar to typeof(T).FullName, but that actually works... ...
(Action<T>).Name does not return expected values
I have the following method (used to generate friendly error messages in unit tests): protected string MethodName<TTestedType>(Action<TTestedType> call) { return string.Format("{0}.{1}", typeof(TTestedType).FullName, call.Method.Name); } But when I call it as follows, I don't get the expected results: var nm = MethodName<MyContro...
Is it possible to tie nested generics?
Is it possible to tie nested generics/captures together? I often have the problem of having a Map lookup of class to genericized item of said class. In concrete terms I want something like this (no, T is not declared anywhere). private Map<Class<T>, ServiceLoader<T>> loaders = Maps.newHashMap(); In short, I want loaders.put/get to ha...
What is the best way to write class template-like generic code in C?
I need to write AVL-tree with generic type in C. The best way I know is to use [ void* ] and to write some functions for creating, copying, assignment and destruction. Please, tell me some better way. ...
How to specify generic method type parameters partly
I have an extension method like below: public static T GetValueAs<T, R>(this IDictionary<string, R> dictionary, string fieldName) where T : R { R value; if (!dictionary.TryGetValue(fieldName, out value)) return default(T); return (T)value; } Currently, I can use it in the following way: var dictionary = n...