Package org.kiwiproject.stream

Class KiwiMultimapCollectors

java.lang.Object

org.kiwiproject.stream.KiwiMultimapCollectors

public final class KiwiMultimapCollectors
extends Object

A Collector that can collect into a Guava Multimap.

Method Summary

Modifier and Type	Method	Description
static <K, V> Collector<Map.Entry<K,V>,com.google.common.collect.Multimap<K,V>,com.google.common.collect.Multimap<K,V>>	toArrayListMultimap()	Collects into an ArrayListMultimap.
static <K, V> Collector<Map.Entry<K,V>,com.google.common.collect.Multimap<K,V>,com.google.common.collect.Multimap<K,V>>	toHashMultimap()	Collects into an HashMultimap.
static <K, V> Collector<Map.Entry<K,V>,com.google.common.collect.Multimap<K,V>,com.google.common.collect.Multimap<K,V>>	toLinkedHashMultimap()	Collects into an LinkedHashMultimap.
static <K, V, A extends com.google.common.collect.Multimap<K, V>> Collector<Map.Entry<K,V>,A,A>	toMultimap(Supplier<A> supplier)	Given a stream of Map.Entry objects, collects to the Multimap specified in the supplier argument.

Methods inherited from class java.lang.Object

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

Method Details

toMultimap

public static <K,
V,
A extends com.google.common.collect.Multimap<K,
V>>
Collector<Map.Entry<K,V>,A,A> toMultimap(Supplier<A> supplier)

Given a stream of Map.Entry objects, collects to the Multimap specified in the supplier argument. This lets you create any type of Multimap you want to collect into. Usually you will use a method reference as the supplier, e.g. ArrayListMultimap:create. You can easily get a stream of Map.Entry objects by getting the map's Map.entrySet() and then calling stream on it, e.g. someMap.entrySet().stream().

Type Parameters:

K - the key type of the Map.Entry objects

V - the value type of the Map.Entry objects

A - the accumulator type, i.e. some kind of Multimap

Parameters:

supplier - the Multimap to collect into

Returns:

the collected Multimap

toArrayListMultimap

public static <K,
V>
Collector<Map.Entry<K,V>,com.google.common.collect.Multimap<K,V>,com.google.common.collect.Multimap<K,V>> toArrayListMultimap()

Collects into an ArrayListMultimap.

Type Parameters:

K - the key type of the Map.Entry objects

V - the value type of the Map.Entry objects

Returns:

the collected ArrayListMultimap

toHashMultimap

public static <K,
V>
Collector<Map.Entry<K,V>,com.google.common.collect.Multimap<K,V>,com.google.common.collect.Multimap<K,V>> toHashMultimap()

Collects into an HashMultimap.

Type Parameters:

K - the key type of the Map.Entry objects

V - the value type of the Map.Entry objects

Returns:

the collected HashMultimap

toLinkedHashMultimap

public static <K,
V>
Collector<Map.Entry<K,V>,com.google.common.collect.Multimap<K,V>,com.google.common.collect.Multimap<K,V>> toLinkedHashMultimap()

Collects into an LinkedHashMultimap.

Type Parameters:

K - the key type of the Map.Entry objects

V - the value type of the Map.Entry objects

Returns:

the collected LinkedHashMultimap