public static <GItem> boolean appendAll(final Collection<GItem> collection, final Iterator<? extends GItem> iterator) throws NullPointerException {
		if (collection == null) throw new NullPointerException("collection = null");
		if (iterator == null) throw new NullPointerException("iterator = null");
		boolean modified = false;
		while (iterator.hasNext()) {
			if (collection.add(iterator.next())) {
				modified = true;
			}
		}
		return modified;
	}