On Aug 4, 2017 2:11 PM, "Gary Gregory" <[email protected]> wrote:
For example, I have a enum like:
public enum CardinalDirection (NORTH,SOUTH,EAST,WEST)
public CardinalDirection nextRandomDirection() {
return rng.next(CardinalDirection.class);
}
This approach may be a bit slow if the random values are near an inner
loop.
In order to select a random enum value, you need to get hold of an array
containing all the possible values (equivalent to what gets returned by the
generated "public static CardinalDirection[] values()".
This requires calling Class::getEnumConstants, which does a little
reflection, caches the result, then returns a clone of the resultant array.
It may be better to construct a random enum value generator object that
holds a copy of the values array, plus an RNG with the desired
characteristics.
A more general method would take an array of values, or a Supplier<T[]>
function (e.g. CardinalDirection::values).
You could use a cache in the RNG, keyed by the class, but that's still
going to be a bit expensive in the middle of a tight loop.
Simon
Simon
