* iterator} method of {@link #entrySet}. If you override {@link #entrySet}, you may wish to
   * override {@link #containsKey} to forward to this implementation.
   *
   * @since 7.0
   */
  protected boolean standardContainsKey(@CheckForNull Object key) {
    return Maps.containsKeyImpl(this, key);
  }

  /**
   * A sensible implementation of {@link Map#values} in terms of the following methods: {@link

      this.backingMap = backingMap;
    }

    @Override
    protected Map<K, V> delegate() {
      return backingMap;
    }

    @Override
    public boolean containsKey(Object key) {
      return standardContainsKey(key);
    }

    @Override
    public boolean containsValue(Object value) {
      return standardContainsValue(value);
    }

    @Override
    public void putAll(Map<? extends K, ? extends V> map) {

      this.backingMap = backingMap;
    }

    @Override
    protected Map<K, V> delegate() {
      return backingMap;
    }

    @Override
    public boolean containsKey(Object key) {
      return standardContainsKey(key);
    }

    @Override
    public boolean containsValue(Object value) {
      return standardContainsValue(value);
    }

    @Override
    public void putAll(Map<? extends K, ? extends V> map) {

   * iterator} method of {@link #entrySet}. If you override {@link #entrySet}, you may wish to
   * override {@link #containsKey} to forward to this implementation.
   *
   * @since 7.0
   */
  protected boolean standardContainsKey(@CheckForNull Object key) {
    return Maps.containsKeyImpl(this, key);
  }

  /**
   * A sensible implementation of {@link Map#values} in terms of the following methods: {@link