Check if a generic T implements an interface

Question

so I have this class in Java:

public class Foo{
}

and inside this class I want to know if T implements certain interface.

The

Answer 1

Generics, oddly enough, use extends for interfaces as well.¹ You'll want to use:

public class Foo{
    //use T as you wish
}

This is actually a requirement for the implementation, not a true/false check.

For a true/false check, use unbounded generics(class Foo{) and make sure you obtain a Class so you have a refiable type:

if(SomeInterface.class.isAssignableFrom(tClazz));

where tClazz is a parameter of type java.lang.Class.

If you get a parameter of refiable type, then it's nothing more than:

if(tParam instanceof SomeInterface){

but this won't work with just the generic declaration.

¹If you want to require extending a class and multiple interfaces, you can do as follows: The class(only one, as there is no multiple inheritance in Java) must go first, and any interfaces after that in any order.