private static final String RESULT_DATA = "SUCCESS";

  private SettableFuture<String> outputFuture;
  // Signals that the function is waiting to complete
  private CountDownLatch funcIsWaitingLatch;
  // Signals the function so it will complete
  private CountDownLatch funcCompletionLatch;

  @Override
  protected ListenableFuture<String> buildChainingFuture(ListenableFuture<Integer> inputFuture) {

  }

  public void complete(RuntimeException e) {
    if (!super.setException(new WrapperException(checkNotNull(e)))) {
      throw new IllegalStateException("Future was already complete: " + this);
    }
  }

  public void complete(Error e) {
    if (!super.setException(new WrapperException(checkNotNull(e)))) {
      throw new IllegalStateException("Future was already complete: " + this);
    }
  }

   * computation is {@linkplain java.util.concurrent.Future#isDone() complete} or, if the
   * computation is already complete, immediately.
   *
   * <p>The callback is run on {@code executor}. There is no guaranteed ordering of execution of
   * callbacks, but any callback added through this method is guaranteed to be called once the
   * computation is complete.
   *
   * <p>Example:
   *
   * <pre>{@code

   * The listener will run when the {@code Future}'s computation is {@linkplain Future#isDone()
   * complete} or, if the computation is already complete, immediately.
   *
   * <p>There is no guaranteed ordering of execution of listeners, but any listener added through
   * this method is guaranteed to be called once the computation is complete.
   *
   * <p>Exceptions thrown by a listener will be propagated up to the executor. Any exception thrown

  }

  public void complete(RuntimeException e) {
    if (!super.setException(new WrapperException(checkNotNull(e)))) {
      throw new IllegalStateException("Future was already complete: " + this);
    }
  }

  public void complete(Error e) {
    if (!super.setException(new WrapperException(checkNotNull(e)))) {
      throw new IllegalStateException("Future was already complete: " + this);
    }
  }

 *
 * <h3>Extension</h3>
 *
 * If you want a class like {@code FluentFuture} but with extra methods, we recommend declaring your
 * own subclass of {@link ListenableFuture}, complete with a method like {@link #from} to adapt an
 * existing {@code ListenableFuture}, implemented atop a {@link ForwardingListenableFuture} that
 * forwards to that future and adds the desired methods.
 */
@GwtCompatible

  private static final String RESULT_DATA = "SUCCESS";

  private SettableFuture<String> outputFuture;
  // Signals that the function is waiting to complete
  private CountDownLatch funcIsWaitingLatch;
  // Signals the function so it will complete
  private CountDownLatch funcCompletionLatch;

  @Override
  protected ListenableFuture<String> buildChainingFuture(ListenableFuture<Integer> inputFuture) {

   * Clears fields that are no longer needed after this future has completed -- or at least all its
   * inputs have completed (more precisely, after {@link #handleAllCompleted()} has been called).
   * Often called multiple times (that is, both when the inputs complete and when the output
   * completes).
   *
   * <p>This is similar to our proposed {@code afterCommit} method but not quite the same. See the
   * description of CL 265462958.
   */

      message += "delay)";
    }
    // It's confusing to see a completed future in a timeout message; if isDone() returns false,
    // then we know it must have given a pending toString value earlier. If not, then the future
    // completed after the timeout expired, and the message might be success.
    if (isDone()) {
      throw new TimeoutException(message + " but future completed as timeout expired");
    }

      }

      /** Transition to the COMPLETED state and set the value. */
      boolean set(@Nullable V v) {
        return complete(v, null, COMPLETED);
      }

      /** Transition to the COMPLETED state and set the exception. */
      boolean setException(Throwable t) {
        return complete(null, t, COMPLETED);
      }

      /** Transition to the CANCELLED or INTERRUPTED state. */