/**
     * Register the given listener which will receive all events.
     *
     * @param listener the listener to register
     * @throws NullPointerException if {@code listener} is null
     */
    void registerListener(@Nonnull Listener listener);

    /**
     * Unregisters a previously registered listener.
     *
     * @param listener the listener to unregister

   *   <li>When a {@code ListenableFuture} listener is registered to run under {@code
   *       directExecutor}, the listener can execute in any of three possible threads:
   *       <ol>
   *         <li>When a thread attaches a listener to a {@code ListenableFuture} that's already
   *             complete, the listener runs immediately in that thread.
   *         <li>When a thread attaches a listener to a {@code ListenableFuture} that's

            configurator = container.lookup(ComponentConfigurator.class, configuratorId);

            ConfigurationListener listener = new DebugConfigurationListener(logger);

            ValidatingConfigurationListener validator =
                    new ValidatingConfigurationListener(mojo, mojoDescriptor, listener);

            if (logger.isDebugEnabled()) {

        ModelBuildingListener listener = getModelBuildingListener(request);

        if (listener != null) {
            AtomicReference<Model> m = new AtomicReference<>(model);

            ModelBuildingEvent event = new DefaultModelBuildingEvent(model, m::set, request, problems);

            catapult.accept(listener, event);

            return m.get();
        }

        void run(AbstractMavenLifecycleParticipant listener, MavenSession session) throws MavenExecutionException;
    }

    private void callListeners(MavenSession session, ListenerMethod method) throws MavenExecutionException {
        ClassLoader originalClassLoader = Thread.currentThread().getContextClassLoader();
        try {
            for (AbstractMavenLifecycleParticipant listener :

    assertNull(segment.refresh(key, hash, identityLoader(), false));
  }

  // Removal listener tests

  public void testRemovalListener_explicit() {
    QueuingRemovalListener<Object, Object> listener = queuingRemovalListener();
    LocalCache<Object, Object> map = makeLocalCache(createCacheBuilder().removalListener(listener));
    assertTrue(listener.isEmpty());

    Object one = new Object();
    Object two = new Object();

    assertNull(segment.refresh(key, hash, identityLoader(), false));
  }

  // Removal listener tests

  public void testRemovalListener_explicit() {
    QueuingRemovalListener<Object, Object> listener = queuingRemovalListener();
    LocalCache<Object, Object> map = makeLocalCache(createCacheBuilder().removalListener(listener));
    assertTrue(listener.isEmpty());

    Object one = new Object();
    Object two = new Object();

      return UNSAFE.compareAndSwapObject(future, LISTENERS_OFFSET, expect, update);
    }

    /** Performs a GAS operation on the {@link #listeners} field. */
    @Override
    Listener gasListeners(AbstractFuture<?> future, Listener update) {
      while (true) {
        Listener listener = future.listeners;
        if (update == listener) {

            this.modelCache = modelCache;
            return this;
        }

        public ModelBuilderRequestBuilder listener(Object listener) {
            this.listener = listener;
            return this;
        }

        public ModelBuilderRequestBuilder interimResult(ModelBuilderResult interimResult) {
            this.interimResult = interimResult;

 * guaranteed to execute. There is no guarantee, however, that listeners will be executed in the
 * order that they are added.
 *
 * <p>Exceptions thrown by a listener will be propagated up to the executor. Any exception thrown
 * during {@code Executor.execute} (e.g., a {@code RejectedExecutionException} or an exception