@NullUnmarked
public class UntrustedInputFutureTest extends AbstractAbstractFutureTest {
  @Override
  AbstractFuture<Integer> newDelegate() {
    AbstractFuture<Integer> future = new AbstractFuture<Integer>() {};
    assertFalse(future instanceof TrustedFuture); // sanity check
    return future;
  }

    extends AbstractFuture.TrustedFuture<OutputT> {
  // Lazily initialized the first time we see an exception; not released until all the input futures
  // & this future completes. Released when the future releases the reference to the running state
  private @Nullable Set<Throwable> seenExceptions = null;
  private int remaining;

  AggregateFutureState(int remainingFutures) {

import static com.google.common.collect.ReflectionFreeAssertThrows.assertThrows;
import static com.google.common.collect.testing.features.CollectionFeature.KNOWN_ORDER;
import static com.google.common.collect.testing.features.CollectionFeature.SERIALIZABLE;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_ANY_NULL_QUERIES;
import static com.google.common.truth.Truth.assertThat;
import static java.util.Collections.emptySet;

Imagine que você tem um aplicativo que permite criar faturas.

Essas faturas terão um `id`, `title` (opcional), `customer` e `total`.

O usuário da sua API (um desenvolvedor externo) criará uma fatura em sua API com uma solicitação POST.

Então sua API irá (vamos imaginar):

* Enviar uma solicitação de pagamento para o desenvolvedor externo.
* Coletar o dinheiro.

 *       hand, is multiple-use, and does implement {@link Iterable}.
 *   <li>Streams offer many features not found here, including {@code min/max}, {@code distinct},
 *       {@code reduce}, {@code sorted}, the very powerful {@code collect}, and built-in support for
 *       parallelizing stream operations.
 *   <li>{@code FluentIterable} contains several features not available on {@code Stream}, which are
 *       noted in the method descriptions below.

 *       hand, is multiple-use, and does implement {@link Iterable}.
 *   <li>Streams offer many features not found here, including {@code min/max}, {@code distinct},
 *       {@code reduce}, {@code sorted}, the very powerful {@code collect}, and built-in support for
 *       parallelizing stream operations.
 *   <li>{@code FluentIterable} contains several features not available on {@code Stream}, which are
 *       noted in the method descriptions below.

          }
        };

    AsyncCallable<String> asyncCallable =
        Callables.asAsyncCallable(callable, newDirectExecutorService());

    ListenableFuture<String> future = asyncCallable.call();
    assertSame(expected, future.get());
  }

  @J2ktIncompatible
  @GwtIncompatible
  public void testAsAsyncCallable_exception() throws Exception {
    Exception expected = new IllegalArgumentException();

    return delegate.submit(task);
  }

  @Override
  public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)
      throws InterruptedException {
    Preconditions.checkNotNull(tasks, "tasks must not be null!");
    return delegate.invokeAll(tasks);
  }

  @Override
  public <T> List<Future<T>> invokeAll(
      Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)

    return delegate.submit(task);
  }

  @Override
  public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks)
      throws InterruptedException {
    Preconditions.checkNotNull(tasks, "tasks must not be null!");
    return delegate.invokeAll(tasks);
  }

  @Override
  public <T> List<Future<T>> invokeAll(
      Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)

    /**
     * Contains the most recently submitted {@code Future}, which may be cancelled or updated,
     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;