@Override
public SortedSet<E> subSet(E fromElement, E toElement) {
Comparator<E> comparator = naturalComparator();
return ((comparator.compare(this.element, toElement) < 0)
&& (comparator.compare(this.element, fromElement) >= 0))
? this
: Collections.<E>emptySortedSet();
}
@Override
public SortedSet<E> tailSet(E fromElement) {
return (naturalComparator().compare(this.element, fromElement) >= 0)
? this
: Collections.<E>emptySortedSet();
}
@Override
public SortedSet<E> headSet(E toElement) {
return (naturalComparator().compare(this.element, toElement) < 0)
? this
: Collections.<E>emptySortedSet();
}
@Test
public void emptySortedSet() {
this.verify(Collections.<Integer>emptySortedSet(), new TreeSet<Integer>(), 0, 1);
}