Method removeOnlyNavigableSet

output/java_guava/1.4.17/Maps.java:1098–1151

(final NavigableSet<E> set)

  }

  @GwtIncompatible // NavigableSet
  private static <E> NavigableSet<E> removeOnlyNavigableSet(final NavigableSet<E> set) {
    return new ForwardingNavigableSet<E>() {
      @Override
      protected NavigableSet<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));
      }

      @Override
      public NavigableSet<E> headSet(E toElement, boolean inclusive) {
        return removeOnlyNavigableSet(super.headSet(toElement, inclusive));
      }

      @Override
      public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
        return removeOnlyNavigableSet(super.tailSet(fromElement, inclusive));
      }

      @Override
      public NavigableSet<E> subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) {
        return removeOnlyNavigableSet(super.subSet(fromElement, fromInclusive, toElement, toInclusive));
      }

      @Override
      public NavigableSet<E> descendingSet() {
        return removeOnlyNavigableSet(super.descendingSet());
      }
    };
  }

  /**
   * Returns an immutable map whose keys are the distinct elements of {@code