Method removeOnlySortedSet

output/java_guava/1.4.17/Maps.java:1064–1096

(final SortedSet<E> set)

  }

  private static <E> SortedSet<E> removeOnlySortedSet(final SortedSet<E> set) {
    return new ForwardingSortedSet<E>() {
      @Override
      protected SortedSet<E> delegate() {
        return set;
      }

      @Override
      public boolean add(E element) {
        throw new UnsupportedOperationException();
      }

      @Override
      public boolean addAll(Collection<? extends E> es) {
        throw new UnsupportedOperationException();
      }

      @Override
      public SortedSet<E> headSet(E toElement) {
        return removeOnlySortedSet(super.headSet(toElement));
      }

      @Override
      public SortedSet<E> subSet(E fromElement, E toElement) {
        return removeOnlySortedSet(super.subSet(fromElement, toElement));
      }

      @Override
      public SortedSet<E> tailSet(E fromElement) {
        return removeOnlySortedSet(super.tailSet(fromElement));
      }
    };
  }

  @GwtIncompatible // NavigableSet
  private static <E> NavigableSet<E> removeOnlyNavigableSet(final NavigableSet<E> set) {