Package org.springframework.data.util

Interface StreamUtils

public interface StreamUtils

Spring Data specific Java Stream utility methods and classes.

Since:

1.10

Author:

Thomas Darimont, Oliver Gierke

Method Summary

Static Methods

Modifier and Type	Method	Description
static <T> Stream<T>	createStreamFromIterator(Iterator<T> iterator)	Returns a Stream backed by the given Iterator
static <T> Stream<T>	createStreamFromIterator(CloseableIterator<T> iterator)	Returns a Stream backed by the given CloseableIterator and forwarding calls to BaseStream.close() to the iterator.
static <T> Stream<T>	fromNullable(@Nullable T source)	Creates a new Stream for the given value returning an empty Stream if the value is null.
static <T, K, V> Collector<T,MultiValueMap<K,V>,MultiValueMap<K,V>>	toMultiMap(Function<T,K> keyFunction, Function<T,V> valueFunction)	Returns a Collector to create a MultiValueMap.
static <T> Collector<T,?,List<T>>	toUnmodifiableList()	Returns a Collector to create an unmodifiable List.
static <T> Collector<T,?,Set<T>>	toUnmodifiableSet()	Returns a Collector to create an unmodifiable Set.
static <L, R, T> Stream<T>	zip(Stream<L> left, Stream<R> right, BiFunction<L,R,T> combiner)	Zips the given Streams using the given BiFunction.

Method Details

createStreamFromIterator

static <T> Stream<T> createStreamFromIterator(Iterator<T> iterator)

Returns a Stream backed by the given Iterator

Parameters:

iterator - must not be null.

Returns:

createStreamFromIterator

static <T> Stream<T> createStreamFromIterator(CloseableIterator<T> iterator)

Returns a Stream backed by the given CloseableIterator and forwarding calls to BaseStream.close() to the iterator.

Parameters:

iterator - must not be null.

Returns:

Since:

2.0

toUnmodifiableList

static <T> Collector<T,?,List<T>> toUnmodifiableList()

Returns a Collector to create an unmodifiable List.

Returns:

will never be null.

toUnmodifiableSet

static <T> Collector<T,?,Set<T>> toUnmodifiableSet()

Returns a Collector to create an unmodifiable Set.

Returns:

will never be null.

toMultiMap

static <T,
K,
V>
Collector<T,MultiValueMap<K,V>,MultiValueMap<K,V>> toMultiMap(Function<T,K> keyFunction,
 Function<T,V> valueFunction)

Returns a Collector to create a MultiValueMap.

Parameters:

keyFunction - Function to create a key from an element of the Stream

valueFunction - Function to create a value from an element of the Stream

fromNullable

static <T> Stream<T> fromNullable(@Nullable T source)

Creates a new Stream for the given value returning an empty Stream if the value is null.

Parameters:

source - can be null.

Returns:

a new Stream for the given value returning an empty Stream if the value is null.

Since:

2.0.6

zip

static <L,
R,
T> Stream<T> zip(Stream<L> left,
 Stream<R> right,
 BiFunction<L,R,T> combiner)

Zips the given Streams using the given BiFunction. The resulting Stream will have the length of the shorter of the two, abbreviating the zipping when the shorter of the two Streams is exhausted.

Parameters:

left - must not be null.

right - must not be null.

combiner - must not be null.

Returns:

Since:

2.1