Module org.omnifaces.utils

Package org.omnifaces.utils.stream

Class Streams

java.lang.Object

org.omnifaces.utils.stream.Streams

public class Streams
extends Object

Constructor Summary

Constructors

Constructor	Description
Streams()

Method Summary

Modifier and Type	Method	Description
static <T,R extends T> Function<T,Stream<R>>	mapToType(Class<R> clazz)	Returns a flatMap Function that only retains a instances of a given type and casts them to this type.
static <T extends Comparable<T>> Stream<T>	range(T start, T endExclusive, Function<? super T,? extends T> incrementer)
static <T> Stream<T>	range(T start, T endExclusive, Function<? super T,? extends T> incrementer, Comparator<? super T> comparator)
static <T extends Comparable<T>> Stream<T>	rangeClosed(T start, T endInclusive, Function<? super T,? extends T> incrementer)
static <T> Stream<T>	rangeClosed(T start, T endInclusive, Function<? super T,? extends T> incrementer, Comparator<? super T> comparator)
static <T> Stream<T>	stream(Iterable<T> iterable)
static <T> Stream<T>	stream(Object object)	Returns a stream of given object.
static <K,V> Stream<Map.Entry<K,V>>	stream(Map<K,V> map)
static <T> Stream<T>	stream(T[] array)
static <T,U,R> Stream<R>	zip(Stream<? extends T> stream1, Stream<? extends U> stream2, BiFunction<? super T,? super U,R> zipFunction)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Streams

public Streams()

Method Detail

zip

public static <T,U,R> Stream<R> zip(Stream<? extends T> stream1,
                                                Stream<? extends U> stream2,
                                                BiFunction<? super T,? super U,R> zipFunction)

rangeClosed

public static <T extends Comparable<T>> Stream<T> rangeClosed(T start,
                                                              T endInclusive,
                                                              Function<? super T,? extends T> incrementer)

rangeClosed

public static <T> Stream<T> rangeClosed(T start,
                                        T endInclusive,
                                        Function<? super T,? extends T> incrementer,
                                        Comparator<? super T> comparator)

range

public static <T extends Comparable<T>> Stream<T> range(T start,
                                                        T endExclusive,
                                                        Function<? super T,? extends T> incrementer)

range

public static <T> Stream<T> range(T start,
                                  T endExclusive,
                                  Function<? super T,? extends T> incrementer,
                                  Comparator<? super T> comparator)

mapToType

public static <T,R extends T> Function<T,Stream<R>> mapToType(Class<R> clazz)

Returns a flatMap Function that only retains a instances of a given type and casts them to this type.

Unlike other flatMap functions, this function will only return 0 or 1 result. If an instance passed to it is of the specified type, then the function will return a Stream with only this item, cast to this type. If the instance is not of this type, the function will return Stream.empty(). Example use Say we have a Stream<X> from which we want retain only all instances of Y, then could do the following to obtain a Stream<Y>: Stream<X> streamOfX = ...; Stream<Y> streamOfY = streamOfX.flatMap(mapToType(Y.class)); Which is the equivalent of this: streamOfX.filter(x -> x instanceof Y) .map(x -> (Y)x)

Type Parameters:

T - the type of the elements in the stream

R - the type of the instances to retain

Parameters:

clazz - the type of the instances to retain

Returns:

a flatMap function that only retains instances of a given type.

stream

public static <T> Stream<T> stream(Object object)

Returns a stream of given object. Supported types are:

• Iterable
• Map (returns a stream of entryset)
• int[]
• long[]
• double[]
• Object[]
• Stream

Anything else is returned as a single-element stream. Null is returned as an empty stream.

Type Parameters:

T - The expected stream type.

Parameters:

object - Any object to get a stream for.

Returns:

A stream of given object.

Throws:

ClassCastException - When T is of wrong type.

stream

public static <T> Stream<T> stream(Iterable<T> iterable)

stream

public static <K,V> Stream<Map.Entry<K,V>> stream(Map<K,V> map)

stream

public static <T> Stream<T> stream(T[] array)