/*
    * Copyright (C) 2009 The Guava Authors
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.google.common.collect;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Set;
  
  import javax.annotation.Nullable;
  
  /**
   * GWT implementation of {@link ImmutableSet} that forwards to another {@code Set} implementation.
   *
   * @author Hayward Chan
   */
  @SuppressWarnings("serial")  // Serialization only done in GWT.
  public abstract class ForwardingImmutableSet<E> extends ImmutableSet<E> {
    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 public boolean contains(@Nullable Object object) {
      return object != null && delegate.contains(object);
    }
  
    @Override public boolean containsAll(Collection<?> targets) {
      return delegate.containsAll(targets);
    }
  
    @Override public int size() {
      return delegate.size();
    }
  
    @Override public boolean isEmpty() {
      return delegate.isEmpty();
    }
  
    @Override public Object[] toArray() {
      return delegate.toArray();
    }
  
    @Override public <T> T[] toArray(T[] other) {
      return delegate.toArray(other);
    }
  
    @Override public String toString() {
      return delegate.toString();
    }
  
    // TODO(cpovirk): equals(), as well, in case it's any faster than Sets.equalsImpl?
  
    @Override public int hashCode() {
      return delegate.hashCode();
    }
  }