class TreeValueSortedMap extends AbstractMap<K, V> implements ValueSortedMap<K, V> {

	@Override
	public boolean isEmpty() {
		return root == null;
	}

	@SuppressWarnings({ "rawtypes", "unchecked" }) protected  TreeValueSortedMap();
	protected  TreeValueSortedMap(Comparator<V> comparator);

}