}

    @Override
    public Iterable<? extends Character> successors(Character node) {
      requestedNodes.add(node);
      return delegate.successors(node);
    }
  }

  private static <N> SuccessorsFunction<N> fixedSuccessors(final Iterable<N> successors) {
    return new SuccessorsFunction<N>() {
      @Override
      public Iterable<N> successors(N n) {
        return successors;

   * they are returned by the iterable's iterator.
   *
   * @since 12.0
   */
  public static <E> ArrayDeque<E> newArrayDeque(Iterable<? extends E> elements) {
    if (elements instanceof Collection) {
      return new ArrayDeque<>((Collection<? extends E>) elements);
    }
    ArrayDeque<E> deque = new ArrayDeque<>();
    Iterables.addAll(deque, elements);
    return deque;

  // Ordering<Iterable<String>> o =
  //     Ordering.<String>natural().lexicographical();
  public <S extends T> Ordering<Iterable<S>> lexicographical() {
    /*
     * Note that technically the returned ordering should be capable of
     * handling not just {@code Iterable<S>} instances, but also any {@code
     * Iterable<? extends S>}. However, the need for this comes up so rarely

  }

  public void testCharacterSimpleSplitWithNoDelimiter() {
    String simple = "a,b,c";
    Iterable<String> letters = Splitter.on('.').split(simple);
    assertThat(letters).containsExactly("a,b,c").inOrder();
  }

  public void testCharacterSplitWithDoubleDelimiter() {
    String doubled = "a,,b,c";
    Iterable<String> letters = COMMA_SPLITTER.split(doubled);
    assertThat(letters).containsExactly("a", "", "b", "c").inOrder();

public class MinimalIterableTest extends TestCase {

  public void testOf_empty() {
    Iterable<String> iterable = MinimalIterable.<String>of();
    Iterator<String> iterator = iterable.iterator();
    assertFalse(iterator.hasNext());
    try {
      iterator.next();
      fail();
    } catch (NoSuchElementException expected) {
    }
    try {
      iterable.iterator();
      fail();
    } catch (IllegalStateException expected) {
    }

    @SuppressWarnings("rawtypes") // the purpose is to test raw type
    Invokable<?, Iterable> delegate =
        Prepender.method("prepend", String.class, Iterable.class).returning(Iterable.class);
    assertEquals(new TypeToken<Iterable<String>>() {}, delegate.getReturnType());
    @SuppressWarnings("unchecked") // prepend() returns Iterable<String>
    Iterable<String> result = delegate.invoke(null, "a", ImmutableList.of("b", "c"));

    public Iterable<UseIterable<? extends Iterable<?>>>
        wildcardOfImplicitBoundedIsSubtypeOfWildcardOfExplicitlyBounded(
            List<UseIterable<?>> withImplicitBounds) {
      return isSubtype(withImplicitBounds);
    }

    @TestSubtype(suppressGetSupertype = true, suppressGetSubtype = true)
    public Iterable<UseSerializableIterable<? extends Iterable<?>>>

  }

  public void testCharacterSimpleSplitWithNoDelimiter() {
    String simple = "a,b,c";
    Iterable<String> letters = Splitter.on('.').split(simple);
    assertThat(letters).containsExactly("a,b,c").inOrder();
  }

  public void testCharacterSplitWithDoubleDelimiter() {
    String doubled = "a,,b,c";
    Iterable<String> letters = COMMA_SPLITTER.split(doubled);
    assertThat(letters).containsExactly("a", "", "b", "c").inOrder();

     *
     * @param <T>
     *            {@link Iterable}の要素型
     * @param iterable
     *            {@link Iterable}。{@literal null}であってはいけません
     * @return {@link IndexedIterator}をラップした{@link Iterable}
     */
    public static <T> Iterable<Indexed<T>> indexed(final Iterable<T> iterable) {
        assertArgumentNotNull("iterable", iterable);

   * always true when the iterable has fewer than two elements.
   */
  public static <T extends @Nullable Object> boolean isInOrder(
      Iterable<? extends T> iterable, Comparator<T> comparator) {
    checkNotNull(comparator);
    Iterator<? extends T> it = iterable.iterator();
    if (it.hasNext()) {
      T prev = it.next();
      while (it.hasNext()) {
        T next = it.next();
        if (comparator.compare(prev, next) > 0) {