latch.await();
    }

    @Override
    protected void triggerShutdown() {
      latch.countDown();
    }

    @Override
    protected String serviceName() {
      return this.getClass().getSimpleName() + "[" + index + "]";
    }
  }

  public void testNulls() {
    ServiceManager manager = new ServiceManager(Arrays.asList());
    new NullPointerTester()

     */
    public void register(final RankFusionSearcher searcher) {
        if (logger.isDebugEnabled()) {
            logger.debug("Registering searcher: {}", searcher.getClass().getSimpleName());
        }
        searchers.add(searcher);
        synchronized (this) {
            if (executorService == null) {

     * Sets up base directory and starts background processing.
     */
    @PostConstruct
    public void init() {
        if (logger.isDebugEnabled()) {
            logger.debug("Initializing {}", this.getClass().getSimpleName());
        }
        final String thumbnailPath = System.getProperty(Constants.FESS_THUMBNAIL_PATH);
        if (thumbnailPath != null) {
            baseDir = new File(thumbnailPath);
        } else {

  /**
   * Returns the name of this service. {@link AbstractScheduledService} may include the name in
   * debugging output.
   *
   * @since 14.0
   */
  protected String serviceName() {
    return getClass().getSimpleName();
  }

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

  @Override
  public final boolean isRunning() {

    @Override
    public E getFirst() {
      synchronized (mutex) {
        return delegate().getFirst();
      }
    }

    @Override
    public E getLast() {
      synchronized (mutex) {
        return delegate().getLast();
      }
    }

    @Override
    public @Nullable E peekFirst() {
      synchronized (mutex) {
        return delegate().peekFirst();
      }
    }

    @Override
    public E getFirst() {
      synchronized (mutex) {
        return delegate().getFirst();
      }
    }

    @Override
    public E getLast() {
      synchronized (mutex) {
        return delegate().getLast();
      }
    }

    @Override
    public @Nullable E peekFirst() {
      synchronized (mutex) {
        return delegate().peekFirst();
      }
    }

        );
    }

    // Helper methods

    private void setPrivateField(Object target, String fieldName, Object value) throws Exception {
        Field field = target.getClass().getDeclaredField(fieldName);
        field.setAccessible(true);
        field.set(target, value);
    }

    private void setResponseAsReceived(Smb2NegotiateResponse resp) throws Exception {

      throw new RuntimeException(e);
    }
  }

  private void checkStackTrace(ExecutionException e) {
    // Our call site for get() should be in the trace.
    int index = findStackFrame(e, getClass().getName(), "getExpectingExecutionException");

    assertThat(index).isNotEqualTo(0);

    // Above our method should be the call to get(). Don't assert on the class
    // because it could be some superclass.

    try {
      new NullPointerTester().testInstanceMethods(instance, visibility);
    } catch (AssertionError expected) {
      return;
    }
    fail("Should detect problem in " + instance.getClass().getSimpleName());
  }

  private static void shouldFail(Object instance) {
    shouldFail(instance, Visibility.PACKAGE);
    shouldFail(instance, Visibility.PROTECTED);

      for (Invokable<?, ?> factory : getFactoriesToTest()) {
        Object instance = instantiate(factory);
        if (instance != null
            && packagesToTest.contains(Reflection.getPackageName(instance.getClass()))) {
          try {
            nullPointerTester.testAllPublicInstanceMethods(instance);
          } catch (AssertionError e) {
            throw new AssertionError("Null check failed on return value of " + factory, e);