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
@ElementTypesAreNonnullByDefault
enum DirectExecutor implements Executor {
  INSTANCE;

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

  @Override

  protected static final boolean expensiveTests = Boolean.getBoolean("jsr166.expensiveTests");

  /**
   * If true, report on stdout all "slow" tests, that is, ones that take more than profileThreshold
   * milliseconds to execute.
   */
  private static final boolean profileTests = Boolean.getBoolean("jsr166.profileTests");

  /**
   * The number of milliseconds that tests are permitted for execution without being reported, when

  /**
   * Returns the {@link Executor} that will be used to run this service. Subclasses may override
   * this method to use a custom {@link Executor}, which may configure its worker thread with a
   * specific name, thread group or priority. The returned executor's {@link
   * Executor#execute(Runnable) execute()} method is called when this service is started and

      TimeUnit unit)
      throws InterruptedException {
    Preconditions.checkNotNull(buffer);
    /*
     * This code performs one System.nanoTime() more than necessary, and in return, the time to
     * execute Queue#drainTo is not added *on top* of waiting for the timeout (which could make
     * the timeout arbitrarily inaccurate, given a queue that is slow to drain).
     */

   */
  protected void triggerShutdown() {}

  /**
   * Returns the {@link Executor} that will be used to run this service. Subclasses may override
   * this method to use a custom {@link Executor}, which may configure its worker thread with a
   * specific name, thread group or priority. The returned executor's {@link
   * Executor#execute(Runnable) execute()} method is called when this service is started, and should
   * return promptly.
   *

      @Override
      public Thread newThread(Runnable r) {
        return new Thread(r);
      }
    }

    public static final class DummyExecutor implements Executor, Serializable {
      @Override
      public void execute(Runnable command) {}
    }
  }

  private static final class NullByteSink extends ByteSink implements Serializable {
    private static final NullByteSink INSTANCE = new NullByteSink();

      @Override
      public Thread newThread(Runnable r) {
        return new Thread(r);
      }
    }

    public static final class DummyExecutor implements Executor, Serializable {
      @Override
      public void execute(Runnable command) {}
    }
  }

  private static final class NullByteSink extends ByteSink implements Serializable {
    private static final NullByteSink INSTANCE = new NullByteSink();

   */
  public static <V extends @Nullable Object> ListenableFuture<V> listenInPoolThread(
      Future<V> future, Executor executor) {
    checkNotNull(executor);
    if (future instanceof ListenableFuture) {
      return (ListenableFuture<V>) future;
    }
    return new ListenableFutureAdapter<>(future, executor);
  }

  /**
   * An adapter to turn a {@link Future} into a {@link ListenableFuture}. This will wait on the

    ExecutorService executor = newDirectExecutorService();
    assertEquals(ImmutableList.of(), executor.shutdownNow());
    assertTrue(executor.isShutdown());
  }

  public void testExecuteAfterShutdown() {
    ExecutorService executor = newDirectExecutorService();
    executor.shutdown();
    assertThrows(RejectedExecutionException.class, () -> executor.execute(EMPTY_RUNNABLE));
  }

        new Service() {
          final NoOpService delegate = new NoOpService();

          @Override
          public final void addListener(Listener listener, Executor executor) {
            service1.startAsync();
            delegate.addListener(listener, executor);
          }

          // Delegates from here on down
          @Override
          public final Service startAsync() {