*
   * @param iterable the iterable to copy
   * @return a newly-allocated array into which all the elements of the iterable have been copied
   */
  static @Nullable Object[] toArray(Iterable<?> iterable) {
    return castOrCopyToCollection(iterable).toArray();
  }

  /**
   * Converts an iterable into a collection. If the iterable is already a collection, it is

   * this method returns {@code true} if {@code iterable1} and {@code iterable2} contain the same
   * number of elements and every element of {@code iterable1} is equal to the corresponding element
   * of {@code iterable2}.
   */
  public static boolean elementsEqual(Iterable<?> iterable1, Iterable<?> iterable2) {
    if (iterable1 instanceof Collection && iterable2 instanceof Collection) {

    Iterable<String> set = Sets.newHashSet("a", "b");
    assertFalse(FluentIterable.from(set).contains("c"));
  }

  public void testContains_nonNullIterableYes() {
    Iterable<String> set = iterable("a", null, "b");
    assertTrue(FluentIterable.from(set).contains("b"));
  }

  public void testContains_nonNullIterableNo() {
    Iterable<String> iterable = iterable("a", "b");

    }
  }

  private void testGetOnAbc(Iterable<String> iterable) {
    try {
      Iterables.get(iterable, -1);
      fail();
    } catch (IndexOutOfBoundsException expected) {
    }
    assertEquals("a", Iterables.get(iterable, 0));
    assertEquals("b", Iterables.get(iterable, 1));
    assertEquals("c", Iterables.get(iterable, 2));
    try {
      Iterables.get(iterable, 3);
      fail();

    }
  }

  private void testGetOnAbc(Iterable<String> iterable) {
    try {
      Iterables.get(iterable, -1);
      fail();
    } catch (IndexOutOfBoundsException expected) {
    }
    assertEquals("a", Iterables.get(iterable, 0));
    assertEquals("b", Iterables.get(iterable, 1));
    assertEquals("c", Iterables.get(iterable, 2));
    try {
      Iterables.get(iterable, 3);
      fail();

    Iterable<String> set = Sets.newHashSet("a", "b");
    assertFalse(FluentIterable.from(set).contains("c"));
  }

  public void testContains_nonNullIterableYes() {
    Iterable<String> set = iterable("a", null, "b");
    assertTrue(FluentIterable.from(set).contains("b"));
  }

  public void testContains_nonNullIterableNo() {
    Iterable<String> iterable = iterable("a", "b");

      Iterable<? extends T> a,
      Iterable<? extends T> b,
      Iterable<? extends T> c,
      Iterable<? extends T> d) {
    return concatNoDefensiveCopy(a, b, c, d);
  }

  /**
   * Returns a fluent iterable that combines several iterables. The returned iterable has an
   * iterator that traverses the elements of each iterable in {@code inputs}. The input iterators
   * are not polled until necessary.
   *

    implements Serializable {
  final Equivalence<E> elementEquivalence;

  PairwiseEquivalence(Equivalence<E> elementEquivalence) {
    this.elementEquivalence = Preconditions.checkNotNull(elementEquivalence);
  }

  @Override
  protected boolean doEquivalent(Iterable<T> iterableA, Iterable<T> iterableB) {
    Iterator<T> iteratorA = iterableA.iterator();

     *
     * @param <E>
     *            要素の型
     * @param iterables
     *            {@link Iterable}の並び。{@literal null}であってはいけません
     * @return {@link MultiIterator}をラップした{@link Iterable}
     */
    public static <E> Iterable<E> iterable(final Iterable<E>... iterables) {
        assertArgumentNotNull("iterables", iterables);

        @SuppressWarnings("unchecked")

public final class IterablesFilterArrayListTest
    extends AbstractFilteredIterableTest<Iterable<Integer>> {
  @Override
  Iterable<Integer> createUnfiltered(Iterable<Integer> contents) {
    return Lists.newArrayList(contents);
  }

  @Override
  Iterable<Integer> filter(Iterable<Integer> elements, Predicate<? super Integer> predicate) {
    return Iterables.filter(elements, predicate);
  }