*
   * @param listener the listener to run when the computation is complete
   * @param executor the executor to run the listener in
   * @throws RejectedExecutionException if we tried to execute the listener immediately but the
   *     executor rejected it.
   */
  void addListener(Runnable listener, Executor executor);

@NullUnmarked
public class ExecutionSequencerTest extends TestCase {

  ExecutorService executor;

  private ExecutionSequencer serializer;
  private SettableFuture<@Nullable Void> firstFuture;
  private TestCallable firstCallable;

  @Override
  public void setUp() throws Exception {
    executor = newCachedThreadPool();
    serializer = ExecutionSequencer.create();
    firstFuture = SettableFuture.create();

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests for {@link ClosingFuture} that exercise {@link
 * ClosingFuture#finishToValueAndCloser(ValueAndCloserConsumer, Executor)}.
 */
@NullUnmarked

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests for {@link ClosingFuture} that exercise {@link
 * ClosingFuture#finishToValueAndCloser(ValueAndCloserConsumer, Executor)}.
 */
@NullUnmarked

package com.google.common.util.concurrent;

import com.google.common.annotations.GwtCompatible;
import java.util.concurrent.Executor;

/**
 * An {@link Executor} that runs each task in the thread that invokes {@link Executor#execute
 * execute}.
 */
@GwtCompatible
enum DirectExecutor implements Executor {
  INSTANCE;

  @Override
  public void execute(Runnable command) {
    command.run();
  }

  @Override

package com.google.common.util.concurrent;

import com.google.common.annotations.GwtCompatible;
import java.util.concurrent.Executor;

/**
 * An {@link Executor} that runs each task in the thread that invokes {@link Executor#execute
 * execute}.
 */
@GwtCompatible
enum DirectExecutor implements Executor {
  INSTANCE;

  @Override
  public void execute(Runnable command) {
    command.run();
  }

  @Override

        }
      }
    }
  }

  /**
   * Checks if the executor has been shut down and increments the running task count.
   *
   * @throws RejectedExecutionException if the executor has been previously shutdown
   */
  private void startTask() {
    synchronized (lock) {
      if (shutdown) {
        throw new RejectedExecutionException("Executor already shutdown");
      }
      runningTasks++;
    }
  }

  }

  public void testTimeout() throws Exception {
    // Create a service whose executor will never run its commands
    Service service =
        new TestService() {
          @Override
          protected Executor executor() {
            return new Executor() {
              @Override
              public void execute(Runnable command) {}
            };
          }

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[14] *}

`.add_task()` recibe como argumentos:

* Una función de tarea para ejecutar en segundo plano (`write_notification`).
* Cualquier secuencia de argumentos que deba pasarse a la función de tarea en orden (`email`).

  }

  public void testTimeout() throws Exception {
    // Create a service whose executor will never run its commands
    Service service =
        new TestService() {
          @Override
          protected Executor executor() {
            return new Executor() {
              @Override
              public void execute(Runnable command) {}
            };
          }