}

    @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);

            org.eclipse.aether.metadata.Metadata metadata,
            ArtifactRepository repository,
            Exception exception) {
        RepositoryListener listener = session.getRepositoryListener();
        if (listener != null) {
            RepositoryEvent.Builder event = new RepositoryEvent.Builder(session, EventType.METADATA_INVALID);
            event.setTrace(trace);
            event.setMetadata(metadata);

- I could make an annotation that marked another class as its plugin discoverer, I could just add it to
  the component descriptor and when it's loaded we can add the discoverer, that would be simpler. I could
  also do this with the lister as well
i'l
// 1 the metadata -> model plugin/mojo descriptor
// 2 tools for doing the mapping
// 3 the component model -> interfaces for the plugin

// The plugin manager should load up a directory structure of plugins.

    /**
     * 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

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

            ConfigurationListener listener = new DebugConfigurationListener(logger);

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

            if (logger.isDebugEnabled()) {

            this.modelResolver = modelResolver;
            return this;
        }

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

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

            VersionRange newRange) {
        for (ResolutionListener listener : listeners) {
            switch (event) {
                case ResolutionListener.TEST_ARTIFACT:
                    listener.testArtifact(node.getArtifact());
                    break;
                case ResolutionListener.PROCESS_CHILDREN:
                    listener.startProcessChildren(node.getArtifact());
                    break;

            org.eclipse.aether.metadata.Metadata metadata,
            ArtifactRepository repository,
            Exception exception) {
        RepositoryListener listener = session.getRepositoryListener();
        if (listener != null) {
            RepositoryEvent.Builder event = new RepositoryEvent.Builder(session, EventType.METADATA_INVALID);
            event.setTrace(trace);
            event.setMetadata(metadata);

        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 :

                events.add(transferEvent);
            }
        }

        TransferListener listener = new TransferListener();
        wagonManager.getArtifact(artifact, repos, listener, false);
        assertEquals(1, listener.events.size());
    }

    @Test
    void testGetMissingJar() throws TransferFailedException, UnsupportedProtocolException, IOException {