How to find an object of class Java generic type?

Question

Suppose I have a generic type Pthat is 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 result in a compilation error because it is P.classnot valid. So what can I do to make the above code work?

Answer 1

You should have a runtime instance of this generic type somewhere, so that you can just grab the declaration class Enum#getDeclaringClass(). Assuming you declared P psomewhere as an argument to a method, here is an example.

eg.

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

Answer 2

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Answer 3

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Answer 4

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class Converter<P extends Enum> {
    private Class<P> type;

    //setter and getter

    public P valueOf(String name) {
        return Enum.valueOf(type, name);
    }
}

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