static <E extends Enum<E>> String toString(EnumSet<E> set) {
			if (set == null || set.isEmpty()) {
				return "";
			} else {
				final StringBuilder b = new StringBuilder();
				final Iterator<E> i = set.iterator();
				b.append(i.next());
				for (; i.hasNext();) {
					b.append(',').append(i.next());
				}
				return b.toString();
			}
		}