* worthwhile only if the precomputed matcher is queried many thousands of times.
   *
   * <p>This method has no effect (returns {@code this}) when called in GWT: it's unclear whether a
   * precomputed matcher is faster, but it certainly consumes more memory, which doesn't seem like a
   * worthwhile tradeoff in a browser.
   */
  public CharMatcher precomputed() {

   *
   * <p><b>{@code Stream} equivalent:</b> {@link java.util.stream.Stream#filter Stream.filter}.
   */
  // TODO(kevinb): how can we omit that Iterables link when building gwt
  // javadoc?
  public static <E extends @Nullable Object> Collection<E> filter(
      Collection<E> unfiltered, Predicate<? super E> predicate) {
    if (unfiltered instanceof FilteredCollection) {

  }

  private static <K, V> ImmutableSetMultimap<K, V> copyOf(
      Multimap<? extends K, ? extends V> multimap,
      @CheckForNull Comparator<? super V> valueComparator) {
    checkNotNull(multimap); // eager for GWT
    if (multimap.isEmpty() && valueComparator == null) {
      return of();
    }

    if (multimap instanceof ImmutableSetMultimap) {
      @SuppressWarnings("unchecked") // safe since multimap is not writable

  }

  private static <K, V> ImmutableSetMultimap<K, V> copyOf(
      Multimap<? extends K, ? extends V> multimap,
      @CheckForNull Comparator<? super V> valueComparator) {
    checkNotNull(multimap); // eager for GWT
    if (multimap.isEmpty() && valueComparator == null) {
      return of();
    }

    if (multimap instanceof ImmutableSetMultimap) {
      @SuppressWarnings("unchecked") // safe since multimap is not writable

 * {@code 0x7F}), and to strings containing such characters.
 *
 * <p>ASCII utilities also exist in other classes of this package:
 *
 * <ul>
 *   <!-- TODO(kevinb): how can we make this not produce a warning when building gwt javadoc? -->
 *   <li>{@link StandardCharsets#US_ASCII} specifies the {@code Charset} of ASCII characters.
 *   <li>{@link CharMatcher#ascii} matches ASCII characters and provides text processing methods

    checkArgument(!token.isEmpty());
    return Ascii.toLowerCase(token);
  }

  private static String normalizeParameterValue(String attribute, String value) {
    checkNotNull(value); // for GWT
    checkArgument(ascii().matchesAllOf(value), "parameter values must be ASCII: %s", value);
    return CHARSET_ATTRIBUTE.equals(attribute) ? Ascii.toLowerCase(value) : value;
  }

  /**

  private static final int ODD_POWERS_OF_TWO = 0xaaaaaaaa;

  @VisibleForTesting
  static boolean isEvenLevel(int index) {
    int oneBased = ~~(index + 1); // for GWT
    checkState(oneBased > 0, "negative index");
    return (oneBased & EVEN_POWERS_OF_TWO) > (oneBased & ODD_POWERS_OF_TWO);
  }

  /**

    assertEquals(asList(3), partitions.get(1));
  }

  @J2ktIncompatible // Arrays.asList(...).subList() doesn't implement RandomAccess in J2KT.
  @GwtIncompatible // ArrayList.subList doesn't implement RandomAccess in GWT.
  public void testPartitionRandomAccessTrue() {
    List<Integer> source = asList(1, 2, 3);
    List<List<Integer>> partitions = partition(source, 2);

    assertTrue(

  private static final long[] VALUES = {MIN_VALUE, (long) -1, (long) 0, (long) 1, MAX_VALUE};

  @GwtIncompatible // Long.hashCode returns different values in GWT.
  public void testHashCode() {
    for (long value : VALUES) {
      assertWithMessage("hashCode for " + value)
          .that(Longs.hashCode(value))
          .isEqualTo(((Long) value).hashCode());
    }
  }

    assertEquals(asList(3), partitions.get(1));
  }

  @J2ktIncompatible // Arrays.asList(...).subList() doesn't implement RandomAccess in J2KT.
  @GwtIncompatible // ArrayList.subList doesn't implement RandomAccess in GWT.
  public void testPartitionRandomAccessTrue() {
    List<Integer> source = asList(1, 2, 3);
    List<List<Integer>> partitions = partition(source, 2);

    assertTrue(