Question

Assume I have a generic type P which is an Enum, that is <P extends Enum<P>>, and I want to get the Enum value from a string, for example:

String foo = "foo";
P fooEnum = Enum.valueOf(P.class, foo);

This will get a compile error because P.class is invalid. So what can I do in order to make the above code work?

Answer 1

You must have a runtime instance of this generic type somewhere so that you can just grab the declaring class by Enum#getDeclaringClass(). Assuming that you’ve declared P p somewhere as a method argument, here’s an example.

E.g.

public static <P extends Enum<P>> P valueOf(P p, String name) {
    return Enum.valueOf(p.getDeclaringClass(), name);
}