*/
@GwtCompatible
public final class Iterables {
  private Iterables() {}

  /** Returns an unmodifiable view of {@code iterable}. */
  public static <T extends @Nullable Object> Iterable<T> unmodifiableIterable(
      Iterable<? extends T> iterable) {
    checkNotNull(iterable);
    if (iterable instanceof UnmodifiableIterable || iterable instanceof ImmutableCollection) {

   * 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) {

    /**
     * Returns an {@link Iterable} that wraps the array for use in a for-each statement.
     *
     * @param <T> the type of elements
     * @param items the array of elements to iterate (must not be {@literal null})
     * @return an {@link Iterable} wrapping the array
     */
    public static <T> Iterable<T> iterable(final T... items) {
        assertArgumentNotNull("items", items);

    /**
     * Returns an {@link Iterable} that wraps a {@link ClassIterator} for use in a for-each statement.
     *
     * @param clazz the class (must not be {@literal null})
     * @return an {@link Iterable} wrapping a {@link ClassIterator}
     */
    public static Iterable<Class<?>> iterable(final Class<?> clazz) {
        return iterable(clazz, true);
    }

    /**

    }

    /**
     * Returns an {@link Iterable} that wraps a {@link LineIterator} for use in enhanced for-loops.
     *
     * @param reader
     *            The {@link BufferedReader} to read strings from. Must not be {@literal null}.
     * @return An {@link Iterable} that wraps a {@link LineIterator}.
     */
    public static Iterable<String> iterable(final BufferedReader reader) {

  }

  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();

    /**
     * Returns an {@link Iterable} that wraps a {@link SingleValueIterator} for use in a for-each statement.
     *
     * @param <E> the element type
     * @param value the single value returned by the iterator
     * @return an {@link Iterable} wrapping a {@link SingleValueIterator}
     */
    public static <E> Iterable<E> iterable(final E value) {
        return () -> new SingleValueIterator<>(value);

      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.
   *

   * already a {@code FluentIterable}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@code iterable.stream()} if {@code iterable} is a {@link
   * Collection}; {@code StreamSupport.stream(iterable.spliterator(), false)} otherwise.
   */
  public static <E extends @Nullable Object> FluentIterable<E> from(Iterable<E> iterable) {
    return (iterable instanceof FluentIterable)
        ? (FluentIterable<E>) iterable

      default:
        return create(elements);
    }
  }

  public static <E> ImmutableSet<E> copyOf(Collection<? extends E> elements) {
    Iterable<? extends E> iterable = elements;
    return copyOf(iterable);
  }

  public static <E> ImmutableSet<E> copyOf(Iterable<? extends E> elements) {
    if (elements instanceof ImmutableSet && !(elements instanceof ImmutableSortedSet)) {