@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class Iterables {
  private Iterables() {}

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

  }

  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();

  int charSplitter(int reps) {
    int total = 0;

    for (int i = 0; i < reps; i++) {
      total += Iterables.size(CHAR_SPLITTER.split(input));
    }

    return total;
  }

  @Benchmark
  int stringSplitter(int reps) {
    int total = 0;

    for (int i = 0; i < reps; i++) {
      total += Iterables.size(STRING_SPLITTER.split(input));
    }

    return total;
  }

public final class MinimalIterable<E extends @Nullable Object> implements Iterable<E> {
  /** Returns an iterable whose iterator returns the given elements in order. */
  public static <E extends @Nullable Object> MinimalIterable<E> of(E... elements) {
    // Make sure to get an unmodifiable iterator
    return new MinimalIterable<>(asList(elements).iterator());
  }

  /**

      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.
   *

import static java.util.concurrent.TimeUnit.SECONDS;

import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;

   * swapping them.
   *
   * <p>An empty iterable has only one permutation, which is an empty list.
   *
   * @param elements the original iterable whose elements have to be permuted.
   * @param comparator a comparator for the iterable's elements.
   * @return an immutable {@link Collection} containing all the different permutations of the
   *     original iterable.

     *
     * @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")

   * 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;

   * 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;