*
   * <p>Cancelling a delegate future propagates to input futures once all the delegates complete,
   * 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

    }

    private final ClosingFuture<V1> future1;
    private final ClosingFuture<V2> future2;
    private final ClosingFuture<V3> future3;

    private Combiner3(
        ClosingFuture<V1> future1, ClosingFuture<V2> future2, ClosingFuture<V3> future3) {
      super(true, ImmutableList.of(future1, future2, future3));
      this.future1 = future1;
      this.future2 = future2;
      this.future3 = future3;
    }

    }

    private final ClosingFuture<V1> future1;
    private final ClosingFuture<V2> future2;
    private final ClosingFuture<V3> future3;

    private Combiner3(
        ClosingFuture<V1> future1, ClosingFuture<V2> future2, ClosingFuture<V3> future3) {
      super(true, ImmutableList.of(future1, future2, future3));
      this.future1 = future1;
      this.future2 = future2;
      this.future3 = future3;
    }

   *   <li>To retrieve a result from a {@code Future} that is already done, use {@link
   *       Futures#getDone Futures.getDone}.
   *   <li>To treat {@link InterruptedException} uniformly with other exceptions, use {@link
   *       Futures#getChecked(Future, Class, long, TimeUnit) Futures.getChecked}.
   *   <li>To get uninterruptibility and remove checked exceptions, use {@link
   *       Futures#getUnchecked}.
   * </ul>
   *

    private final ListenableFuture<@Nullable Void> future;
    private boolean called = false;

    private TestCallable(ListenableFuture<@Nullable Void> future) {
      this.future = future;
    }

    @Override
    public ListenableFuture<@Nullable Void> call() throws Exception {
      called = true;
      return future;
    }
  }

  CollectionFuture(
      ImmutableCollection<? extends ListenableFuture<? extends V>> futures,
      boolean allMustSucceed) {
    super(futures, allMustSucceed, true);

    List<@Nullable Present<V>> values =
        futures.isEmpty()
            ? Collections.<@Nullable Present<V>>emptyList()
            : Lists.<@Nullable Present<V>>newArrayListWithCapacity(futures.size());

    // Populate the results list with null initially.

    if (state != State.NOT_DONE && (numListeners != 0 || numThreads != 0)) {
      throw new SkipThisScenarioException();
    }
  }

  // This exclusion doesn't exclude the TOMBSTONE objects we set. So 'done' NEW futures will look
  // larger than they are.
  @SuppressWarnings("FutureReturnValueIgnored")
  @Footprint(exclude = {Runnable.class, Executor.class, Thread.class, Exception.class})
  public Object measureSize() {

  static <V extends @Nullable Object, X extends Exception> V getChecked(
      Future<V> future, Class<X> exceptionClass) throws X {
    return getChecked(bestGetCheckedTypeValidator(), future, exceptionClass);
  }

  /** Implementation of {@link Futures#getChecked(Future, Class)}. */
  @CanIgnoreReturnValue
  @VisibleForTesting
  @ParametricNullness
  static <V extends @Nullable Object, X extends Exception> V getChecked(

      List<Future<String>> futures = testExecutor.invokeAll(tasks);
      mock.assertLastMethodCalled("invokeAll");
      checkResults(futures);
    }
    {
      MockExecutor mock = new MockExecutor();
      TimeUnit unit = SECONDS;
      long timeout = 5;
      TestExecutor testExecutor = new TestExecutor(mock);
      List<Future<String>> futures = testExecutor.invokeAll(tasks, timeout, unit);

import com.google.common.annotations.J2ktIncompatible;

/**
 * Hidden superclass of {@link Futures} that provides us a place to declare special GWT versions of
 * the {@link Futures#catching(ListenableFuture, Class, com.google.common.base.Function,
 * java.util.concurrent.Executor) Futures.catching} family of methods. Those versions have slightly
 * different signatures.
 */
@GwtCompatible