if (future.listenersField == expect) {
          future.listenersField = update;
          return true;
        }
        return false;
      }
    }

    @Override
    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      synchronized (future) {
        Listener old = future.listenersField;
        if (old != update) {
          future.listenersField = update;

  private final FluentFuture<V> future;

  private ClosingFuture(ListenableFuture<V> future) {
    this(future, new CloseableList());
  }

  private ClosingFuture(ListenableFuture<V> future, CloseableList closeables) {
    this.future = FluentFuture.from(future);
    this.closeables = closeables;
  }

  /**

        try {
          assertEquals("hello", data);
          future.complete(null);
        } catch (Exception e) {
          future.completeExceptionally(e);
        }
      }

      @Override
      public void onClosed(@NotNull EventSource eventSource) {
        future.completeExceptionally(new IllegalStateException("closed"));
      }

      @Override

  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(

  /**
   * 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}.
   */

@GwtCompatible
public interface FutureCallback<V extends @Nullable Object> {
  /** Invoked with the result of the {@code Future} computation when it is successful. */
  void onSuccess(@ParametricNullness V result);

  /**
   * Invoked when a {@code Future} computation fails or is canceled.
   *
   * <p>If the future's {@link Future#get() get} method throws an {@link ExecutionException}, then

import java.util.concurrent.Executor;
import java.util.concurrent.Future;
import java.util.concurrent.RejectedExecutionException;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A {@link Future} that accepts completion listeners. Each listener has an associated executor, and
 * it is invoked using this executor once the future's computation is {@linkplain Future#isDone()

import java.util.concurrent.Executor;
import java.util.concurrent.Future;
import java.util.concurrent.RejectedExecutionException;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A {@link Future} that accepts completion listeners. Each listener has an associated executor, and
 * it is invoked using this executor once the future's computation is {@linkplain Future#isDone()

        try {
            Future<List<FileNotifyInformation>> future = executor.submit(() -> blockingHandle.watch());

            // Verify timeout occurs
            assertThrows(TimeoutException.class, () -> {
                future.get(100, TimeUnit.MILLISECONDS);
            });

            // Cancel the future
            future.cancel(true);
        } finally {

        /**
         * Gets the future for asynchronous notification completion
         * @return the notification future
         */
        public CompletableFuture<Void> getNotificationFuture() {
            return notificationFuture;
        }

        /**
         * Sets the future for asynchronous notification completion
         * @param future the notification future to set
         */