* java.util.concurrent.CompletableFuture#thenAcceptAsync}.
   *
   * @param callback The callback to invoke when this {@code Future} is completed.
   * @param executor The executor to run {@code callback} when the future completes.
   */
  public final void addCallback(FutureCallback<? super V> callback, Executor executor) {
    Futures.addCallback(this, callback, executor);
  }

    MockCallback callback = new MockCallback("foo");
    addCallback(f, callback, directExecutor());
    f.set("foo");
  }

  public void testExecutorSuccess() {
    CountingSameThreadExecutor ex = new CountingSameThreadExecutor();
    SettableFuture<String> f = SettableFuture.create();
    MockCallback callback = new MockCallback("foo");
    Futures.addCallback(f, callback, ex);
    f.set("foo");

    boolean ran = false;
    @Nullable Callback callback = null;

    public SimpleTearDown() {}

    public SimpleTearDown(Callback callback) {
      this.callback = callback;
    }

    @Override
    public void tearDown() throws Exception {
      if (callback != null) {
        callback.run();
      }
      ran = true;
    }
  }

      Class<Throwable> exceptionType,
      Function<? super Throwable, ? extends V> fallback,
      Executor executor) {
    return (FluentFuture<V>) Futures.catching(this, exceptionType, fallback, executor);
  }

  public final FluentFuture<V> catchingAsync(
      Class<Throwable> exceptionType,
      AsyncFunction<? super Throwable, ? extends V> fallback,
      Executor executor) {

  public void testOr_supplier_present() {
    assertEquals("a", Optional.of("a").or(Suppliers.ofInstance("fallback")));
  }

  public void testOr_supplier_absent() {
    assertEquals("fallback", Optional.absent().or(Suppliers.ofInstance("fallback")));
  }

  public void testOr_nullSupplier_absent() {

 * and performant but introduces some testing difficulties. This test exercises the two fallback
 * strategies.
 *
 * <ul>
 *   <li>SafeAtomicHelper: uses Atomic FieldsUpdaters to implement synchronization
 *   <li>SynchronizedHelper: uses {@code synchronized} blocks for synchronization
 * </ul>
 *
 * To force selection of our fallback strategies we load {@link AggregateFutureState} (and all of

   * for bridge methods.
   */
  public void testRegistrationWithBridgeMethod() {
    final AtomicInteger calls = new AtomicInteger();
    bus.register(
        new Callback<String>() {
          @Subscribe
          @Override
          public void call(String s) {
            calls.incrementAndGet();
          }
        });

    bus.post("hello");

   * for bridge methods.
   */
  public void testRegistrationWithBridgeMethod() {
    final AtomicInteger calls = new AtomicInteger();
    bus.register(
        new Callback<String>() {
          @Subscribe
          @Override
          public void call(String s) {
            calls.incrementAndGet();
          }
        });

    bus.post("hello");

      queue.dispatch();
    } finally {
      logger.removeHandler(logHandler);
    }

    assertEquals(1, logHandler.getStoredLogRecords().size());
    assertEquals(
        "Exception while executing callback: MyListener custom-label",
        logHandler.getStoredLogRecords().get(0).getMessage());
  }

  public void testEnqueueAndDispatch_multithreaded() throws InterruptedException {
    Object listener = new Object();

  }

  /**
   * This tests for a bug where if {@link Service#stopAsync()} was called while the service was
   * {@link State#STARTING} more than once, the {@link Listener#stopping(State)} callback would get
   * called multiple times.
   */
  public void testManualServiceStopMultipleTimesWhileStarting() throws Exception {
    ManualSwitchedService service = new ManualSwitchedService();