import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;

/**
 * A listener for session events.
 * TODO: open this to other events like similar to {@code org.apache.maven.eventspy.EventSpy}
 *
 * @since 4.0.0
 */
@Experimental
@FunctionalInterface
@Consumer
public interface Listener {
    void onEvent(@Nonnull Event event);

  private static final ListenerCallQueue.Event<Listener> STARTING_EVENT =
      new ListenerCallQueue.Event<Listener>() {
        @Override
        public void call(Listener listener) {
          listener.starting();
        }

        @Override
        public String toString() {
          return "starting()";
        }
      };
  private static final ListenerCallQueue.Event<Listener> RUNNING_EVENT =

   * after executing them.
   *
   * @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);

  protected SettableFuture<Integer> inputFuture;
  protected ListenableFuture<T> resultFuture;
  protected MockFutureListener listener;

  @Override
  protected void setUp() throws Exception {
    super.setUp();

    inputFuture = SettableFuture.create();
    resultFuture = buildChainingFuture(inputFuture);
    listener = new MockFutureListener(resultFuture);
  }

  public void testFutureGetBeforeCallback() throws Exception {

        return super.getIfNewer(resourceName, destination, timestamp);
    }

    public void addTransferListener(TransferListener listener) {
        if (listener instanceof TestTransferListener) {
            testTransferListener = (TestTransferListener) listener;
        }
        super.addTransferListener(listener);
    }

    RecordingListener listener = new RecordingListener();
    manager.addListener(listener, directExecutor());
    manager.startAsync().awaitHealthy();
    assertTrue(manager.isHealthy());
    assertTrue(listener.healthyCalled);
    assertFalse(listener.stoppedCalled);
    assertTrue(listener.failedServices.isEmpty());
    manager.stopAsync().awaitStopped();

        private final GenerationListener listener;

        private UnknownJavadocTagHandler(DocBookBuilder nodes, Document document, GenerationListener listener) {
            this.nodes = nodes;
            this.document = document;
            this.listener = listener;
        }

        @Override
        public boolean onJavadocTag(String tag, String value) {

        for (MojoExecutionListener listener : listeners) {
            listener.afterExecutionFailure(event);
        }
    }

    public void addMojoExecutionListener(MojoExecutionListener listener) {
        this.listeners.add(listener);
    }

    public void removeMojoExecutionListener(MojoExecutionListener listener) {
        this.listeners.remove(listener);
    }

 * shared resources.
 *
 * @param <K> the most general type of keys this listener can listen for; for example {@code Object}
 *     if any key is acceptable
 * @param <V> the most general type of values this listener can listen for; for example {@code
 *     Object} if any key is acceptable
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible

    }

    @Override
    public void registerListener(@Nonnull Listener listener) {
        listeners.add(nonNull(listener));
    }

    @Override
    public void unregisterListener(@Nonnull Listener listener) {
        listeners.remove(nonNull(listener));
    }

    @Nonnull
    @Override
    public Collection<Listener> getListeners() {
        return Collections.unmodifiableCollection(listeners);