Java: Array of primitive data types does not autobox
There is no autoboxing for arrays, only for primitives. I believe this is your problem.
generics
Convert existing generics to diamond syntax
Oh yes, I have successfully done this on IntelliJ (free Community Edition). Menu > Analyze > Inspect Code… In the result, select “Java language level migration aids > Explicity type can be replaced with <>” Right click, run “Apply Fix ‘Replace with <>’” And you got diamonds. There was a bug about diamond on anomymous … Read more
C++ equivalent of using for a java parameter/return type
Technically, as the other answers show, there are ways to restrict it to subtypes of a certain type at compile time. However, most of the time, you would just do template <typename T> T foo(T bar) {…} without needing to specify a bound. In Java, bounds are needed for generics because the generic class or … Read more
Why doesn’t ICollection implement ICollection? [duplicate]
As Nick said, ICollection is pretty much useless. These interfaces are similar only by their name, CopyTo and Count are the only properties in common. Add, Remove, Clear, Contains and IsReadOnly have been added while IsSychronized and SyncRoot have been removed. In essence, ICollection<T> is mutable, ICollection is not. Krzysztof Cwalina has more on this … Read more
Generics compilation error with ternary operator in Java 8, but not in Java 7
I’m going to go out on a limb and say that this error (while it may or may not conform to the updated JLS, which I admit I haven’t read in detail) is due to an inconsistency in type handling by the JDK 8 compiler. In general the ternary operator used the same type inference … Read more
Loop over values in an IEnumerable using reflection
foreach (var property in yourObject.GetType().GetProperties()) { if (property.PropertyType.GetInterfaces().Contains(typeof(IEnumerable))) { foreach (var item in (IEnumerable)property.GetValue(yourObject, null)) { //do stuff } } }
Wildcard equivalent in C# generics
Generics in C# make stronger guarantees than generics in Java. Therefore, to do what you want in C#, you have to let the GeneralPropertyMap<T> class inherit from a non-generic version of that class (or interface). public class GeneralPropertyMap<T> : GeneralPropertyMap { } public class GeneralPropertyMap { // Only you can implement it: internal GeneralPropertyMap() { … Read more
C# interface static method call with generics
Try an extension method instead: public interface IMyInterface { string GetClassName(); } public static class IMyInterfaceExtensions { public static void PrintClassName<T>( this T input ) where T : IMyInterface { Console.WriteLine(input.GetClassName()); } } This allows you to add static extension/utility method, but you still need an instance of your IMyInterface implementation. You can’t have interfaces … Read more
Declare a generic type instance dynamically [duplicate]
If you don’t know the type at compile-time, but you want the actual type (i.e. not List<object>) and you’re not in a generic method/type with the appropriate type parameter, then you have to use reflection. To make the reflection simpler, I’ve sometimes introduced a new generic type or method in my own code, so I … Read more