Java: How to write generic function that accepts Enum constants that implement a given interface?

Question

So i have a bunch of enum's that all extend an interface:

public interface MyInterface {}

I then have several enums that extend the interface:

public enum A implements MyInterface {}

public enum B implements MyInterface {}

I want a function that will accept only enum's that extend this interface. I cannot do:

public void MyFunction(MyInterface input)

because, inside the function, I create an EnumSet using EnumSet.of(input). I cannod do

public <T extends Enum<T>> void myFunction(T input)

because, inside the function, I need to create a Map that needs to be passed to another function. So is there any type-safe way to do this w/o casting?

Edit: Corrected interface definitions.

That should be `enum A implements MyInterface` – Rohit Jain Feb 11 '14 at 16:43 — Rohit Jain, Feb 11 '14 at 16:43

score 13 · Accepted Answer · answered Feb 11 '14 at 16:40

You can give multiple bounds to your type parameter:

public <T extends Enum<T> & MyInterface> void myFunction(T input)

Note: You're missing return type of the method. I've given void here. Change accordingly. Oh! And please follow Java naming conventions. Method name should start with lowercase letters.

Java: How to write generic function that accepts Enum constants that implement a given interface?

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