Creates an enum set initialized from the specified collection. If the specified collection is an EnumSet instance, this static factory method behaves identically to copyOf(EnumSet). Otherwise, the specified collection must contain at least one element (in order to determine the new enum set's element type).

Parameters:

<E>		The class of the elements in the collection
c		the collection from which to initialize this enum set

Returns:  An enum set initialized from the given collection.

Exceptions:

IllegalArgumentException		if c is not an EnumSet instance and contains no elements
NullPointerException		if c is null