private final Collection<MojoExecutionListener> listeners;

    CompoundMojoExecutionListener(Collection<MojoExecutionListener> listeners) {
        this.listeners = listeners; // NB this is live injected collection
    }

    public void beforeMojoExecution(MojoExecutionEvent event) throws MojoExecutionException {
        for (MojoExecutionListener listener : listeners) {
            listener.beforeMojoExecution(event);
        }
    }

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

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

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

        return updateScope;
    }

    private void fireEvent(int event, List<ResolutionListener> listeners, ResolutionNode node) {
        fireEvent(event, listeners, node, null);
    }

    private void fireEvent(int event, List<ResolutionListener> listeners, ResolutionNode node, Artifact replacement) {
        fireEvent(event, listeners, node, replacement, null);
    }

    private void fireEvent(
            int event,

    checkNotNull(unit);
    return get();
  }

  @Override
  public void addListener(Runnable runnable, Executor executor) {
    Listener listener = new Listener(runnable, executor);
    if (isDone()) {
      listener.execute();
    } else {
      listeners.add(listener);
    }
  }

  @CanIgnoreReturnValue
  protected boolean setException(Throwable throwable) {
    checkNotNull(throwable);

    Listener listener;
    synchronized (this) {
      listener = listeners.get(state);
    }

    if (code == null || listener == null) {
      return new MockResponse()
          .setResponseCode(404)
          .setBody("unexpected request");
    }

    try {
      OAuthSession session = slackApi.exchangeCode(code, redirectUrl());
      listener.sessionGranted(session);

  }

  /** @since 13.0 */
  @Override
  public final void addListener(Listener listener, Executor executor) {
    listeners.addListener(listener, executor);
  }

  @Override
  public String toString() {
    return getClass().getSimpleName() + " [" + state() + "]";
  }

  /**
   * Attempts to execute all the listeners in {@link #listeners} while not holding the {@link
   * #monitor}.
   */

    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();

    exec.shutdown();
    exec.awaitTermination(100, MILLISECONDS);
  }

  /**
   * Tests that all listeners complete, even if they were added before or after the future was
   * finishing. Also acts as a concurrency test to make sure the locking is done correctly when a
   * future is finishing so that no listeners can be lost.
   */
  public void testAllListenersCompleteSuccessfully()

    if (!isDone()) {
      Listener oldHead = listeners;
      if (oldHead != Listener.TOMBSTONE) {
        Listener newNode = new Listener(listener, executor);
        do {
          newNode.next = oldHead;
          if (ATOMIC_HELPER.casListeners(this, oldHead, newNode)) {
            return;
          }
          oldHead = listeners; // re-read
        } while (oldHead != Listener.TOMBSTONE);

        for (ProjectExecutionListener listener : listeners) {
            listener.afterProjectExecutionFailure(event);
        }
    }

    public void addProjectExecutionListener(ProjectExecutionListener listener) {
        this.listeners.add(listener);
    }

    public void removeProjectExecutionListener(ProjectExecutionListener listener) {
        this.listeners.remove(listener);
    }