*
 * <p>An instance of this class is serializable if its reference is absent or is a serializable
 * object.
 *
 * <p><b>Comparison to {@code java.util.Optional} (JDK 8 and higher):</b> A new {@code Optional}
 * class was added for Java 8. The two classes are extremely similar, but incompatible (they cannot
 * share a common supertype). <i>All</i> known differences are listed either here or with the

    return result;
  }

  boolean removeIf(BiPredicate<? super K, ? super V> filter) {
    checkNotNull(filter);
    boolean changed = false;
    for (K key : keySet()) {
      while (true) {
        V value = get(key);
        if (value == null || !filter.test(key, value)) {
          break;
        } else if (LocalCache.this.remove(key, value)) {
          changed = true;

    FINITE_DOUBLE_CANDIDATES =
        Iterables.concat(FRACTIONAL_DOUBLE_CANDIDATES, INTEGRAL_DOUBLE_CANDIDATES);
    POSITIVE_FINITE_DOUBLE_CANDIDATES =
        Iterables.filter(
            FINITE_DOUBLE_CANDIDATES,
            new Predicate<Double>() {
              @Override
              public boolean apply(Double input) {
                return input.doubleValue() > 0.0;

    assertEquals("FooBar{}", toTest);
  }

  @GwtIncompatible // Class names are obfuscated in GWT
  public void testToStringHelper_localInnerClass() {
    // Local inner classes have names ending like "Outer.$1Inner"
    class LocalInnerClass {}
    String toTest = MoreObjects.toStringHelper(new LocalInnerClass()).toString();
    assertEquals("LocalInnerClass{}", toTest);
  }

                unfiltered.add("zzz");
                unfiltered.add("abc");
                return Collections2.filter(Collections2.filter(unfiltered, LENGTH_1), NOT_YYY_ZZZ);
              }
            })
        .named("Collections2.filter, filtered input")
        .withFeatures(
            CollectionFeature.SUPPORTS_ADD,
            CollectionFeature.SUPPORTS_REMOVE,

                unfiltered.add("zzz");
                unfiltered.add("abc");
                return Collections2.filter(Collections2.filter(unfiltered, LENGTH_1), NOT_YYY_ZZZ);
              }
            })
        .named("Collections2.filter, filtered input")
        .withFeatures(
            CollectionFeature.SUPPORTS_ADD,
            CollectionFeature.SUPPORTS_REMOVE,

  @Override
  NavigableSet<Integer> createUnfiltered(Iterable<Integer> contents) {
    return Sets.newTreeSet(contents);
  }

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

  @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);
  }

    assertThat(stream(FluentIterable.of(1, 2, 3)).filter(n -> n > 1)).containsExactly(2, 3);
  }

  @SuppressWarnings("deprecation")
  public void testStream_collection() {
    assertThat(stream(Arrays.asList())).isEmpty();
    assertThat(stream(Arrays.asList("a"))).containsExactly("a");
    assertThat(stream(Arrays.asList(1, 2, 3)).filter(n -> n > 1)).containsExactly(2, 3);
  }

   */
  // 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) {
      // Support clear(), removeAll(), and retainAll() when filtering a filtered
      // collection.