Class<X> exceptionType,
      Function<? super X, ? extends V> fallback,
      Executor executor) {
    CatchingFuture<V, X> future = new CatchingFuture<>(input, exceptionType, fallback);
    input.addListener(future, rejectionPropagatingExecutor(executor, future));
    return future;
  }

  static <X extends Throwable, V extends @Nullable Object> ListenableFuture<V> create(
      ListenableFuture<? extends V> input,

    } finally {
      Thread.interrupted();
    }
  }

  public void testGetUnchecked_cancelled() {
    SettableFuture<String> future = SettableFuture.create();
    future.cancel(true);
    try {
      getUnchecked(future);
      fail();
    } catch (CancellationException expected) {
    }
  }

  public void testGetUnchecked_ExecutionExceptionChecked() {
    try {

    } finally {
      Thread.interrupted();
    }
  }

  public void testGetUnchecked_cancelled() {
    SettableFuture<String> future = SettableFuture.create();
    future.cancel(true);
    try {
      getUnchecked(future);
      fail();
    } catch (CancellationException expected) {
    }
  }

  public void testGetUnchecked_ExecutionExceptionChecked() {
    try {

  static final Future<String> FAILED_FUTURE_ERROR = immediateFailedFuture(ERROR);
  static final Future<String> RUNTIME_EXCEPTION_FUTURE =
      UncheckedThrowingFuture.throwingRuntimeException(RUNTIME_EXCEPTION);
  static final Future<String> ERROR_FUTURE = UncheckedThrowingFuture.throwingError(ERROR);

  public static final class TwoArgConstructorException extends Exception {

import java.util.concurrent.Future;
import org.checkerframework.checker.nullness.qual.Nullable;

/** Emulation of Uninterruptibles in GWT. */
@ElementTypesAreNonnullByDefault
public final class Uninterruptibles {

  private Uninterruptibles() {}

  @CanIgnoreReturnValue
  public static <V extends @Nullable Object> V getUninterruptibly(Future<V> future)
      throws ExecutionException {
    try {

      Thread.interrupted();
    }
  }

  public void testGetCheckedUntimed_cancelled() throws TwoArgConstructorException {
    SettableFuture<String> future = SettableFuture.create();
    future.cancel(true);
    assertThrows(
        CancellationException.class, () -> getChecked(future, TwoArgConstructorException.class));
  }

  public void testGetCheckedUntimed_ExecutionExceptionChecked() {
    TwoArgConstructorException expected =

      Thread.interrupted();
    }
  }

  public void testGetCheckedUntimed_cancelled() throws TwoArgConstructorException {
    SettableFuture<String> future = SettableFuture.create();
    future.cancel(true);
    assertThrows(
        CancellationException.class, () -> getChecked(future, TwoArgConstructorException.class));
  }

  public void testGetCheckedUntimed_ExecutionExceptionChecked() {
    TwoArgConstructorException expected =

  @CanIgnoreReturnValue
  @ParametricNullness
  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

  @CanIgnoreReturnValue
  protected boolean setFuture(ListenableFuture<? extends V> future) {
    checkNotNull(future);

    // If this future is already cancelled, cancel the delegate.
    // TODO(cpovirk): Should we do this at the end of the method, as in the server version?
    // TODO(cpovirk): Use maybePropagateCancellationTo?
    if (isCancelled()) {
      future.cancel(mayInterruptIfRunning);
    }

  /**
   * Returns an output {@code Future} to use in place of the given {@code input}. The output {@code
   * Future} need not be {@linkplain Future#isDone done}, making {@code AsyncFunction} suitable for
   * asynchronous derivations.
   *
   * <p>Throwing an exception from this method is equivalent to returning a failing {@code Future}.
   */