Re: Random Enum

Eric Sosman <esosman@ieee-dot-org.invalid>
Mon, 24 Aug 2009 22:00:16 -0400
Lew wrote:

If you can pass a Class instance to the method, as Eric Sosman

public class RandomEnum // untested, not even compiled yet
  private static final Random rand = new Random();

  public static <E extends Enum<E>> E random( Class <E> clazz )
    E [] values = clazz.getEnumConstants();
    return values [rand.nextInt( values.length )];

As to Eric's fear that this is "unpleasantly intricate", we just have
to get over it.

In use it's very simple. Given an enum 'Foo':

  Foo value = RandomEnum.random( Foo.class );

     Thanks, Lew: My fears are (mostly) allayed. It looks like
type inference saves the day; I was worried that the caller
might have to write out a great big generic gobbledegook just
to invoke the method.

     And I stand by my remarks on the usefulness of not limiting
the operation to enums alone, but on letting it work with many
kinds of groupings: arrays, Collections, and sequences.

Eric Sosman

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