Java Enums: List enumerated values from a Class<? extends Enum>

Question

I\'ve got the class object for an enum (I have a Class) and I need to get a list of the enumerated values represented by this enum. The

Answer 1

I am suprised to see that EnumSet#allOf() is not mentioned:

public static > EnumSet allOf(Class elementType)

Creates an enum set containing all of the elements in the specified element type.

Consider the following enum:

enum MyEnum {
  TEST1, TEST2
}

Simply call the method like this:

Set allElementsInMyEnum = EnumSet.allOf(MyEnum.class);

Of course, this returns a Set, not a List, but it should be enough in many (most?) use cases.

Or, if you have an unknown enum:

Class enumClass = MyEnum.class;
Set allElementsInMyEnum = EnumSet.allOf(enumClass);

The advantage of this method, compared to Class#getEnumConstants(), is that it is typed so that it is not possible to pass anything other than an enum to it. For example, the below code is valid and returns null:

String.class.getEnumConstants();

While this won't compile:

EnumSet.allOf(String.class); // won't compile