RegularImmutableAsList(ImmutableCollection<E> delegate, ImmutableList<? extends E> delegateList) {
    this.delegate = delegate;
    this.delegateList = delegateList;
  }

  RegularImmutableAsList(ImmutableCollection<E> delegate, Object[] array) {
    this(delegate, ImmutableList.<E>asImmutableList(array));
  }

  @Override
  ImmutableCollection<E> delegateCollection() {
    return delegate;
  }

  private final transient Set<E> delegate;

  ForwardingImmutableSet(Set<E> delegate) {
    // TODO(cpovirk): are we over-wrapping?
    this.delegate = Collections.unmodifiableSet(delegate);
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return Iterators.unmodifiableIterator(delegate.iterator());
  }

  @Override

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

  @CanIgnoreReturnValue
  @Override
  public int drainTo(Collection<? super E> c, int maxElements) {
    return delegate().drainTo(c, maxElements);
  }

  @CanIgnoreReturnValue
  @Override
  public int drainTo(Collection<? super E> c) {
    return delegate().drainTo(c);
  }

  @CanIgnoreReturnValue // TODO(kak): consider removing this

  }

  private InvalidatableSet(
      Set<E> delegate, Supplier<Boolean> validator, Supplier<String> errorMessage) {
    this.delegate = delegate;
    this.validator = validator;
    this.errorMessage = errorMessage;
  }

  // Override hashCode() to access delegate directly (so that it doesn't trigger the validate() call
  // via delegate()); it seems inappropriate to throw ISE on this method.
  @Override
  public int hashCode() {

  private final ListenableFuture<V> delegate;

  ForwardingFluentFuture(ListenableFuture<V> delegate) {
    this.delegate = checkNotNull(delegate);
  }

  @Override
  public void addListener(Runnable listener, Executor executor) {
    delegate.addListener(listener, executor);
  }

  @Override
  public boolean cancel(boolean mayInterruptIfRunning) {
    return delegate.cancel(mayInterruptIfRunning);
  }

   *
   * @since 10.0
   */
  public abstract static class SimpleForwardingLoadingCache<K, V>
      extends ForwardingLoadingCache<K, V> {
    private final LoadingCache<K, V> delegate;

    protected SimpleForwardingLoadingCache(LoadingCache<K, V> delegate) {
      this.delegate = Preconditions.checkNotNull(delegate);
    }

    @Override
    protected final LoadingCache<K, V> delegate() {

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

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

  @Override
  public NavigableSet<E> elementSet() {
    return delegate().elementSet();
  }

  /**
   * A sensible implementation of {@link SortedMultiset#elementSet} in terms of the following

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

  @Override
  public void add(@ParametricNullness E element) {
    delegate().add(element);
  }

  @Override
  public boolean hasPrevious() {
    return delegate().hasPrevious();
  }

  @Override
  public int nextIndex() {
    return delegate().nextIndex();
  }

  @CanIgnoreReturnValue
  @Override

    implements SortedMultiset<E> {
  UnmodifiableSortedMultiset(SortedMultiset<E> delegate) {
    super(delegate);
  }

  @Override
  protected SortedMultiset<E> delegate() {
    return (SortedMultiset<E>) super.delegate();
  }

  @Override
  public Comparator<? super E> comparator() {
    return delegate().comparator();
  }

  @Override
  SortedSet<E> createElementSet() {

need it so that empty directory does not get deleted...