import jsinterop.annotations.JsType;
import org.jspecify.annotations.Nullable;

/**
 * Java super source for ListenableFuture, implementing a structural thenable via a default method.
 * For restrictions, please refer to the documentation of the then() method.
 */
public interface ListenableFuture<V extends @Nullable Object> extends Future<V>, IThenable<V> {
  void addListener(Runnable listener, Executor executor);

 * ListenableFuture}</a>.
 *
 * <p>This class is GWT-compatible.
 *
 * <h3>Purpose</h3>
 *
 * <p>The main purpose of {@code ListenableFuture} is to help you chain together a graph of
 * asynchronous operations. You can chain them together manually with calls to methods like {@link
 * Futures#transform(ListenableFuture, com.google.common.base.Function, Executor) Futures.transform}

 * ListenableFuture}</a>.
 *
 * <p>This class is GWT-compatible.
 *
 * <h3>Purpose</h3>
 *
 * <p>The main purpose of {@code ListenableFuture} is to help you chain together a graph of
 * asynchronous operations. You can chain them together manually with calls to methods like {@link
 * Futures#transform(ListenableFuture, com.google.common.base.Function, Executor) Futures.transform}

 * ListenableFuture}</a>.
 *
 * <p>This class is GWT-compatible.
 *
 * <h3>Purpose</h3>
 *
 * <p>The main purpose of {@code ListenableFuture} is to help you chain together a graph of
 * asynchronous operations. You can chain them together manually with calls to methods like {@link
 * Futures#transform(ListenableFuture, com.google.common.base.Function, Executor) Futures.transform}

   * #setFuture(ListenableFuture)}.
   */
  private static final class AsyncTransformFuture<
          I extends @Nullable Object, O extends @Nullable Object>
      extends AbstractTransformFuture<
          I, O, AsyncFunction<? super I, ? extends O>, ListenableFuture<? extends O>> {
    AsyncTransformFuture(

      Future<V> future) {
    if (future instanceof ListenableFuture) {
      return (ListenableFuture<V>) future;
    }
    return new ListenableFutureAdapter<>(future);
  }

  /**
   * Submits a blocking task for the given {@link Future} to provide {@link ListenableFuture}
   * functionality.
   *
   * <p><b>Warning:</b> If the input future does not already implement {@code ListenableFuture}, the

 * own subclass of {@link ListenableFuture}, complete with a method like {@link #from} to adapt an
 * existing {@code ListenableFuture}, implemented atop a {@link ForwardingListenableFuture} that
 * forwards to that future and adds the desired methods.
 */
@GwtCompatible
final class ForwardingFluentFuture<V extends @Nullable Object> extends FluentFuture<V> {
  private final ListenableFuture<V> delegate;

import org.jspecify.annotations.Nullable;

/**
 * A {@link ListenableFuture} whose result can be set by a {@link #set(Object)}, {@link
 * #setException(Throwable)} or {@link #setFuture(ListenableFuture)} call. It can also, like any
 * other {@code Future}, be {@linkplain #cancel cancelled}.
 *
 * <p>{@code SettableFuture} is the recommended {@code ListenableFuture} implementation when your

    return delegate.awaitTermination(timeout, unit);
  }

  @Override
  public <T> ListenableFuture<T> submit(Callable<T> task) {
    Preconditions.checkNotNull(task, "task must not be null!");
    return delegate.submit(task);
  }

  @Override
  public <T> ListenableFuture<T> submit(Runnable task, T result) {
    Preconditions.checkNotNull(task, "task must not be null!");

    return delegate.awaitTermination(timeout, unit);
  }

  @Override
  public <T> ListenableFuture<T> submit(Callable<T> task) {
    Preconditions.checkNotNull(task, "task must not be null!");
    return delegate.submit(task);
  }

  @Override
  public <T> ListenableFuture<T> submit(Runnable task, T result) {
    Preconditions.checkNotNull(task, "task must not be null!");