public <T> T[] toArray(T[] array) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.toArray(array);
    }

    @Override
    public void addFirst(E e) {
      assertTrue(Thread.holdsLock(mutex));
      delegate.addFirst(e);
    }

    @Override
    public void addLast(E e) {
      assertTrue(Thread.holdsLock(mutex));
      delegate.addLast(e);
    }

    @Override

  /** Constructor for use by subclasses. */
  protected ForwardingDeque() {}

  @Override
  protected abstract Deque<E> delegate();

  @Override
  public void addFirst(@ParametricNullness E e) {
    delegate().addFirst(e);
  }

  @Override
  public void addLast(@ParametricNullness E e) {
    delegate().addLast(e);
  }

  @Override
  public Iterator<E> descendingIterator() {

  /** Constructor for use by subclasses. */
  protected ForwardingDeque() {}

  @Override
  protected abstract Deque<E> delegate();

  @Override
  public void addFirst(@ParametricNullness E e) {
    delegate().addFirst(e);
  }

  @Override
  public void addLast(@ParametricNullness E e) {
    delegate().addLast(e);
  }

  @Override
  public Iterator<E> descendingIterator() {

    @Override
    public void warning(String message) {
        LOGGER.warn(String.format("%s: %s", contextStack.getFirst(), message));
    }

    @Override
    public void start(String context) {
        contextStack.addFirst(context);
    }

    @Override
    public void finish() {
        contextStack.removeFirst();
    }

     * </p>
     *
     * @param disposable
     *            破棄可能なリソース。{@literal null}であってはいけません
     */
    public static synchronized void addFirst(final Disposable disposable) {
        assertArgumentNotNull("disposable", disposable);
        disposables.addFirst(disposable);
    }

    /**
     * 破棄可能なリソースを登録解除します。
     *
     * @param disposable
     *            破棄可能なリソース。{@literal null}であってはいけません
     */

            } else if (!blockContent.contains(name) && !(name.equals("a") && attributes.containsKey("name"))) {
                onInlineContent();
            }

            elementStack.addFirst(name);
            visitor.onStartHtmlElement(name);
            for (Map.Entry<String, String> entry : attributes.entrySet()) {
                visitor.onHtmlElementAttribute(entry.getKey(), entry.getValue());
            }

        assertThat(list.getLast(), is("1"));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testAddFirst() throws Exception {
        list.addFirst("1");
        list.addFirst("2");
        assertThat(list.getFirst(), is("2"));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testAddLast() throws Exception {

class DocBookBuilder {
    final LinkedList<Element> stack = new LinkedList<Element>();
    final Document document;

    DocBookBuilder(Document document) {
        this.document = document;
        stack.addFirst(document.createElement("root"));
    }

    List<Element> getElements() {
        List<Element> elements = new ArrayList<Element>();

    public <T> T[] toArray(T[] array) {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.toArray(array);
    }

    @Override
    public void addFirst(E e) {
      assertTrue(Thread.holdsLock(mutex));
      delegate.addFirst(e);
    }

    @Override
    public void addLast(E e) {
      assertTrue(Thread.holdsLock(mutex));
      delegate.addLast(e);
    }

    @Override

    public void enter() {
        LinkedList<ScopeState> stack = values.get();
        if (stack == null) {
            stack = new LinkedList<>();
            values.set(stack);
        }
        stack.addFirst(new ScopeState());
    }

    private ScopeState getScopeState() {
        LinkedList<ScopeState> stack = values.get();
        if (stack == null || stack.isEmpty()) {
            throw new IllegalStateException();