Question

I have a method on which I need to pass an enum as a parameter.

public <T> T doSomething(SomeEnum operation, Class<T> something);

I have several enums and the method is a common one which should work with any enums. What is the correct way to write this method signature to accept any generic enum types? I know that I can use a marker interface to this purpose, but I would like to write it with generic enum signatures. Please advise me on this.

Whats the bad idea with the below one: (It works but I get warnings from IDE saying it is a raw type. I’m not clear about the reason).

 public void doSomething(Enum operation);

Answer 1

public <E extends Enum<E>> void doSomething(E operation);

EDIT: An example according to your modifications:

public class Main {

    public enum Day {
        SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
        THURSDAY, FRIDAY, SATURDAY 
    }

    public <E extends Enum<E>> E doSomething(E operation, Class<E> klazz) {

        return operation;
    }

    public static void main(String[] args) {

        new Main().doSomething(Day.FRIDAY, Day.class);
    }

}

EDIT2:

if you need T and the Enum as separate types, then you’ll need:

public <T, E extends Enum<E>> T doSomething(E operation, Class<T> klazz) {