pure interface of interface java.util.SortedSet<A>

public interface SortedSet<A>
  implements Set<A>
{
    public abstract Comparator<A> comparator();
    public abstract SortedSet<A> subSet(A fromElement,
                                        A toElement);
    public abstract SortedSet<A> headSet(A toElement);
    public abstract SortedSet<A> tailSet(A fromElement);
    public abstract A first();
    public abstract A last();
}