Class CollectionUtil

Method Details

• close

  public static void close(Object... closeables)

  Since:

  3.29

• dump

  public static <T> Iterator<T> dump(Iterator<T> it)

• topologicalSort

  public static <NODE> List<NODE> topologicalSort(Collection<NODE> nodes, Function<NODE,Collection<NODE>> edgeProvider)

  Since:

  3.25

• topologicalSort

  public static <NODE> List<NODE> topologicalSort(Collection<NODE> nodes, Function<NODE,Collection<NODE>> edgeProvider, boolean reverse)

  Since:

  3.25

• addNotNull

  public static <T> boolean addNotNull(Collection<? super T> c, T e)

  Since:

  3.16

• setOf

  public static <T> Set<T> setOf(Collection<? extends T> c)

  Since:

  3.16

• first

  public static <T> T first(Collection<? extends T> c)

  Since:

  3.16

• removeAll

  public static <K, V> List<K> removeAll(Map<K,V> map, BiPredicate<K,V> predicate)

  Since:

  3.16

• compute

  public static <K, V> V compute(Map<K,V> map, K key, BiFunction<? super K,? super V,? extends V> remappingFunction)

  Since:

  3.16

• subclasses

  public static <SUBTYPE, TYPE extends SUBTYPE> Function<? super SUBTYPE,? extends Stream<? extends TYPE>> subclasses(Class<TYPE> clazz)

  Returns a function that returns a stream containing the given object if it is an instance of the given class; otherwise an empty stream.

  Example usage:

   Stream<Animal> animals = Stream.of(new Dog(), new Cat(), new Bird());
   Stream<Dog> dogs = animals.flatMap(CollectionUtil.subclasses(Dog.class));
   

  This example creates a stream of animals and then uses the subclasses function to filter and cast the stream to only include instances of Dog. This is a little easier to read and remember than using filter and map separately, as the following equivalent code shows:

   Stream<Dog> dogs = animals
      .filter(Dog.class::isInstance)
      .map(Dog.class::cast);
   

  Since:

  3.29

• stream

  public static <T> Stream<T> stream(Iterator<T> it)

  Returns a stream over the elements of the given iterator.

  Since:

  3.29

• concat

  @SafeVarargs public static <T> Stream<T> concat(Stream<T>... streams)

  Returns a stream that concatenates the given streams.

  Since:

  3.26

• concat

  public static <T> Stream<T> concat(Collection<Stream<T>> streams)

  Returns a stream that concatenates the given streams.

  Since:

  3.26