final Document document;

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

    List<Element> getElements() {
        List<Element> elements = new ArrayList<Element>();
        for (Node node = stack.getLast().getFirstChild(); node != null; node = node.getNextSibling()) {
            elements.add((Element) node);
        }

 * supplied by the user of the class. For example, {@code Multiset.Entry.getElement()} returns
 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *

 * supplied by the user of the class. For example, {@code Multiset.Entry.getElement()} returns
 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *

        assertThat(indexed1.getElement(), is("aaa"));

        final Indexed<String> indexed2 = it.next();
        assertThat(indexed2.getIndex(), is(1));
        assertThat(indexed2.getElement(), is("bbb"));

        final Indexed<String> indexed3 = it.next();
        assertThat(indexed3.getIndex(), is(2));
        assertThat(indexed3.getElement(), is("ccc"));

        assertThat(it.hasNext(), is(not(true)));

    Iterator<Entry<E>> entryIterator = entrySet().iterator();
    if (!entryIterator.hasNext()) {
      return null;
    }
    Entry<E> entry = entryIterator.next();
    return Multisets.immutableEntry(entry.getElement(), entry.getCount());
  }

  @Override
  @CheckForNull
  public Entry<E> lastEntry() {
    return delegate().lastEntry();
  }

  /**

        list.addLast("1");
        list.addLast("2");
        list.addLast("3");
        assertThat(list.getEntry(0).getElement(), is("1"));
        assertThat(list.getEntry(1).getElement(), is("2"));
        assertThat(list.getEntry(2).getElement(), is("3"));
        try {
            list.getEntry(-1);
            fail();
        } catch (final ClIndexOutOfBoundsException ex) {

 * supplied by the user of the class. For example, {@code Multiset.Entry.getElement()} returns
 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *

 * supplied by the user of the class. For example, {@code Multiset.Entry.getElement()} returns
 * {@code @ParametricNullness E}, which means:
 *
 * <ul>
 *   <li>{@code getElement} on a {@code Multiset.Entry<@NonNull String>} returns {@code @NonNull
 *       String}.
 *   <li>{@code getElement} on a {@code Multiset.Entry<@Nullable String>} returns {@code @Nullable
 *       String}.
 * </ul>
 *

    Iterator<Entry<E>> entryIterator = entrySet().iterator();
    if (!entryIterator.hasNext()) {
      return null;
    }
    Entry<E> entry = entryIterator.next();
    return Multisets.immutableEntry(entry.getElement(), entry.getCount());
  }

  @Override
  @CheckForNull
  public Entry<E> lastEntry() {
    return delegate().lastEntry();
  }

  /**

          return new Multisets.AbstractEntry<E>() {
            @Override
            public E getElement() {
              return mapEntry.getKey();
            }

            @Override
            public int getCount() {
              Integer frequency = backingMap.get(getElement());
              return (frequency == null) ? 0 : frequency;
            }
          };
        }
      };