* <p><b>{@code Stream} equivalent:</b> {@link Stream#filter}.
   */
  public static <T extends @Nullable Object> Iterable<T> filter(
      final Iterable<T> unfiltered, final Predicate<? super T> retainIfTrue) {
    checkNotNull(unfiltered);
    checkNotNull(retainIfTrue);
    return new FluentIterable<T>() {
      @Override
      public Iterator<T> iterator() {
        return Iterators.filter(unfiltered.iterator(), retainIfTrue);
      }

   * <p><b>{@code Stream} equivalent:</b> {@link Stream#filter} (same).
   */
  public final FluentIterable<E> filter(Predicate<? super E> predicate) {
    return from(Iterables.filter(getDelegate(), predicate));
  }

  /**
   * Returns the elements from this fluent iterable that are instances of class {@code type}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@code stream.filter(type::isInstance).map(type::cast)}.

              // We can't check that the key is mightContain() == false before the
              // put() because the key could have already been generated *or* the
              // bloom filter might say true even when it's not there (false
              // positive).
              bloomFilter.put(key);
              // False negative should *never* happen.

   * will not reflect any subsequent changes to the cause chain.
   *
   * <p>Here's an example of how it can be used to find specific types of exceptions in the cause
   * chain:
   *
   * <pre>
   * Iterables.filter(Throwables.getCausalChain(e), IOException.class));
   * </pre>
   *
   * @param throwable the non-null {@code Throwable} to extract causes from

  }

  private static Type[] toArray(Collection<Type> types) {
    return types.toArray(new Type[0]);
  }

  private static Iterable<Type> filterUpperBounds(Iterable<Type> bounds) {
    return Iterables.filter(bounds, Predicates.not(Predicates.<Type>equalTo(Object.class)));
  }

  private static void disallowPrimitiveType(Type[] types, String usedAs) {
    for (Type type : types) {
      if (type instanceof Class) {

   * will not reflect any subsequent changes to the cause chain.
   *
   * <p>Here's an example of how it can be used to find specific types of exceptions in the cause
   * chain:
   *
   * <pre>
   * Iterables.filter(Throwables.getCausalChain(e), IOException.class));
   * </pre>
   *
   * @param throwable the non-null {@code Throwable} to extract causes from

                SortedMultiset<E> multiset =
                    (SortedMultiset<E>) delegate.create(allEntries.toArray());

                // call the smallest subMap overload that filters out the extreme
                // values
                if (from == Bound.INCLUSIVE) {
                  multiset = multiset.tailMultiset(firstInclusive, BoundType.CLOSED);

                SortedMultiset<E> multiset =
                    (SortedMultiset<E>) delegate.create(allEntries.toArray());

                // call the smallest subMap overload that filters out the extreme
                // values
                if (from == Bound.INCLUSIVE) {
                  multiset = multiset.tailMultiset(firstInclusive, BoundType.CLOSED);

  public void testFilter() {
    FluentIterable<String> filtered =
        FluentIterable.from(asList("foo", "bar")).filter(Predicates.equalTo("foo"));

    List<String> expected = Collections.singletonList("foo");
    List<String> actual = Lists.newArrayList(filtered);
    assertEquals(expected, actual);
    assertCanIterateAgain(filtered);
    assertEquals("[foo]", filtered.toString());
  }

  private static class TypeA {}

  }

  public void testAccept() {
    File dir = new File("foo");
    FilenameFilter filter = new PatternFilenameFilter("a+");
    assertTrue(filter.accept(dir, "a"));
    assertTrue(filter.accept(dir, "aaaa"));
    assertFalse(filter.accept(dir, "b"));

    // Show that dir is ignored
    assertTrue(filter.accept(null, "a"));
  }

  public void testNulls() throws Exception {