@Override
  @ParametricNullness
  public E removeFirst() {
    return delegate().removeFirst();
  }

  @CanIgnoreReturnValue
  @Override
  @ParametricNullness
  public E removeLast() {
    return delegate().removeLast();
  }

  @CanIgnoreReturnValue
  @Override
  public boolean removeFirstOccurrence(@CheckForNull Object o) {
    return delegate().removeFirstOccurrence(o);
  }

                if (superClassSymbol == superSymbol) {
                    result = stack.toList()
                    check(stack.removeLast().second == superClassSymbol)
                    break
                }
                dfs(superClassSymbol)
                check(stack.removeLast().second == superClassSymbol)
            }
        }

        dfs(baseSymbol)
        return result?.reversed()
    }

    @Override
    public E removeFirst() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.removeFirst();
    }

    @Override
    public E removeLast() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.removeLast();
    }

    @Override
    public @Nullable E pollFirst() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.pollFirst();
    }

    @Override
    public E removeFirst() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.removeFirst();
    }

    @Override
    public E removeLast() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.removeLast();
    }

    @Override
    public @Nullable E pollFirst() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.pollFirst();
    }

  @Override
  @ParametricNullness
  public E removeFirst() {
    return delegate().removeFirst();
  }

  @CanIgnoreReturnValue
  @Override
  @ParametricNullness
  public E removeLast() {
    return delegate().removeLast();
  }

  @CanIgnoreReturnValue
  @Override
  public boolean removeFirstOccurrence(@CheckForNull Object o) {
    return delegate().removeFirstOccurrence(o);
  }

                    List<String> ret = visitCycle(graph, graph.get(v), stateMap, cycle);
                    if (ret != null) {
                        return ret;
                    }
                    cycle.removeLast();
                    stateMap.put(v, DfsState.VISITED);
                } else if (state == DfsState.VISITING) {
                    // we are already visiting this vertex, this mean we have a cycle

                cycle.addLast(v.label);
                List<String> ret = visitCycle(v.children, stateMap, cycle);
                if (ret != null) {
                    return ret;
                }
                cycle.removeLast();
                stateMap.put(v, DfsState.VISITED);
            } else if (state == DfsState.VISITING) {
                // we are already visiting this vertex, this mean we have a cycle

    }

    @Override
    public T next() {
      Iterator<T> itr = stack.getLast(); // throws NSEE if empty
      T result = checkNotNull(itr.next());
      if (!itr.hasNext()) {
        stack.removeLast();
      }
      Iterator<T> childItr = children(result).iterator();
      if (childItr.hasNext()) {
        stack.addLast(childItr);
      }
      return result;
    }
  }

  /**

    }

    /**
     * 登録済みのリソースを全て破棄します。
     */
    public static synchronized void dispose() {
        while (!disposables.isEmpty()) {
            final Disposable disposable = disposables.removeLast();
            try {
                disposable.dispose();
            } catch (final Throwable t) {
                t.printStackTrace(); // must not use Logger.
            }
        }
        disposables.clear();

            } catch (Exception e) {
                throw new ClassDocGenerationException("Could not load the class documentation for class '$className'.", e)
            }
        } finally {
            currentlyBuilding.removeLast()
        }
    }

    private File getFileForClass(String className) {
        File classFile = new File(classDocbookDir, "${className}.xml")
        classFile
    }