/**
   * Returns the backing delegate instance that methods are forwarded to. Abstract subclasses
   * generally override this method with an abstract method that has a more specific return type,
   * such as {@link ForwardingSet#delegate}. Concrete subclasses override this method to supply the
   * instance being decorated.
   */
  protected abstract Object delegate();

                      @Override
                      public Set<Entry<String>> entrySet() {
                        final Set<Entry<String>> backingSet = super.entrySet();
                        return new ForwardingSet<Entry<String>>() {
                          @Override
                          protected Set<Entry<String>> delegate() {
                            return backingSet;
                          }

 *
 * @author Mike Bostock
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class ForwardingSortedSet<E extends @Nullable Object> extends ForwardingSet<E>
    implements SortedSet<E> {

  /** Constructor for use by subclasses. */
  protected ForwardingSortedSet() {}

  @Override
  protected abstract SortedSet<E> delegate();

  @Override
  @CheckForNull

                      @Override
                      public Set<Entry<String>> entrySet() {
                        final Set<Entry<String>> backingSet = super.entrySet();
                        return new ForwardingSet<Entry<String>>() {
                          @Override
                          protected Set<Entry<String>> delegate() {
                            return backingSet;
                          }

        cast(getKey(), value);
        return super.setValue(value);
      }
    };
  }

  @Override
  public Set<Entry<Class<? extends @NonNull B>, B>> entrySet() {
    return new ForwardingSet<Entry<Class<? extends @NonNull B>, B>>() {

      @Override
      protected Set<Entry<Class<? extends @NonNull B>, B>> delegate() {
        return MutableClassToInstanceMap.this.delegate().entrySet();
      }

          return true;
        }
      }
    }
    return false;
  }

  // Views

  @Override
  Set<E> createElementSet() {
    Set<E> delegate = countMap.keySet();
    return new ForwardingSet<E>() {
      @Override
      protected Set<E> delegate() {
        return delegate;
      }

      @Override
      public boolean contains(@CheckForNull Object object) {

              .that(immutableCopy)
              .isIn(distinctCandidatesByAscendingSize);
        }
      }
    }
  }

  private static final class MutatedOnQuerySet<E> extends ForwardingSet<E> {
    final Iterator<ImmutableSet<E>> infiniteCandidates;

    MutatedOnQuerySet(Iterable<ImmutableSet<E>> infiniteCandidates) {
      this.infiniteCandidates = infiniteCandidates.iterator();
    }

    CountingSupplier<Set<Integer>> factory =
        new SetSupplier() {
          @Override
          public Set<Integer> getImpl() {
            final Set<Integer> backing = super.getImpl();
            return new ForwardingSet<Integer>() {
              @Override
              protected Set<Integer> delegate() {
                return backing;
              }

              @Override

      return asMap(set.descendingSet(), function);
    }
  }

  private static <E extends @Nullable Object> Set<E> removeOnlySet(final Set<E> set) {
    return new ForwardingSet<E>() {
      @Override
      protected Set<E> delegate() {
        return set;
      }

      @Override
      public boolean add(@ParametricNullness E element) {

      return asMap(set.descendingSet(), function);
    }
  }

  private static <E extends @Nullable Object> Set<E> removeOnlySet(final Set<E> set) {
    return new ForwardingSet<E>() {
      @Override
      protected Set<E> delegate() {
        return set;
      }

      @Override
      public boolean add(@ParametricNullness E element) {