public boolean cancel(boolean mayInterruptIfRunning) {
    logger.get().log(FINER, "cancelling {0}", this);
    boolean cancelled = future.cancel(mayInterruptIfRunning);
    if (cancelled) {
      close();
    }
    return cancelled;
  }

  private void close() {
    logger.get().log(FINER, "closing {0}", this);
    closeables.close();
  }

 * A {@link ListenableFuture} whose result can be set by a {@link #set(Object)}, {@link
 * #setException(Throwable)} or {@link #setFuture(ListenableFuture)} call. It can also, like any
 * other {@code Future}, be {@linkplain #cancel cancelled}.
 *
 * <p>{@code SettableFuture} is the recommended {@code ListenableFuture} implementation when your
 * task cannot be implemented with {@link ListeningExecutorService}, the various {@link Futures}

   * either from cancellation or because an input future has completed. If N futures are passed in,
   * and M delegates are cancelled, the remaining M input futures will be cancelled once N - M of
   * the input futures complete. If all the delegates are cancelled, all the input futures will be
   * too.
   *
   * @since 17.0
   */

      return;
    }

    /*
     * Any of the setException() calls below can fail if the output Future is cancelled between now
     * and then. This means that we're silently swallowing an exception -- maybe even an Error. But
     * this is no worse than what FutureTask does in that situation. Additionally, because the
     * Future was cancelled, its listeners have been run, so its consumers will not hang.
     *

            }

          case CANCELLED:
          case INTERRUPTED:
            throw cancellationExceptionWithCause("Task was cancelled.", exception);

          default:
            throw new IllegalStateException("Error, synchronizer in invalid state: " + state);
        }
      }

      /** Checks if the state is {@link #COMPLETED}, {@link #CANCELLED}, or {@link #INTERRUPTED}. */
      boolean isDone() {

      // before the cancelled future completes, it will synchronously complete both the newFuture
      // from the cancelled operation and its own. This can cause one runnable to queue two tasks,
      // breaking the invariant this method relies on to iteratively run the next task after the
      // previous one completes.
      if (get() == RunningState.CANCELLED) {
        delegate = null;
        sequencer = null;

  public boolean cancel(boolean mayInterruptIfRunning) {
    logger.get().log(FINER, "cancelling {0}", this);
    boolean cancelled = future.cancel(mayInterruptIfRunning);
    if (cancelled) {
      close();
    }
    return cancelled;
  }

  private void close() {
    logger.get().log(FINER, "closing {0}", this);
    closeables.close();
  }

/** Measures the size of AbstractFuture implementations. */
@NullUnmarked
public class AbstractFutureFootprintBenchmark {

  enum State {
    NOT_DONE,
    FINISHED,
    CANCELLED,
    FAILED
  }

  @Param State state;
  @Param Impl impl;

  @Param({"0", "1", "5", "10"})
  int numListeners;

  @Param({"0", "1", "5", "10"})
  int numThreads;

   * input future and that of the future returned by the chain function. That is, if the returned
   * {@code Future} is cancelled, it will attempt to cancel the other two, and if either of the
   * other two is cancelled, the returned {@code Future} will receive a callback in which it will
   * attempt to cancel itself.
   *

  override fun completed(response: SimpleHttpResponse) {
  }

  override fun failed(ex: Exception) {
    println("Failed: $ex")
  }

  override fun cancelled() {
    println("Cancelled")
  }