@Override
    public boolean contains(@CheckForNull Object rowKey, @CheckForNull Object columnKey) {
      synchronized (mutex) {
        return delegate().contains(rowKey, columnKey);
      }
    }

    @Override
    public boolean containsRow(@CheckForNull Object rowKey) {
      synchronized (mutex) {
        return delegate().containsRow(rowKey);
      }
    }

    @Override

    final AbstractFuture<V> owner;
    final ListenableFuture<? extends V> future;

    SetFuture(AbstractFuture<V> owner, ListenableFuture<? extends V> future) {
      this.owner = owner;
      this.future = future;
    }

    @Override
    public void run() {
      if (owner.value != this) {
        // nothing to do, we must have been cancelled, don't bother inspecting the future.
        return;

  }

  /**
   * Determines whether a BMP character is lower case according to {@linkplain
   * Character#isLowerCase(char) Java's definition}.
   *
   * @deprecated Some lowercase characters are supplementary characters; see the class
   *     documentation.
   * @since 19.0 (since 1.0 as constant {@code JAVA_LOWER_CASE})
   */
  @Deprecated
  public static CharMatcher javaLowerCase() {

  }

  /**
   * Determines whether a BMP character is lower case according to {@linkplain
   * Character#isLowerCase(char) Java's definition}.
   *
   * @deprecated Some lowercase characters are supplementary characters; see the class
   *     documentation.
   * @since 19.0 (since 1.0 as constant {@code JAVA_LOWER_CASE})
   */
  @Deprecated
  public static CharMatcher javaLowerCase() {