net.sergeych.collections

Class Multimap<K,V>

java.lang.Object

net.sergeych.collections.Multimap<K,V>

Type Parameters:

K -

V -

public class Multimap<K,V>
extends java.lang.Object

Multimap (AKA bag) associates any number of elements with a key. It could be constructed using any Map and any Collection using the constructor. Note that this implementation is not synchronized and not yet very well tested.

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.Map<K,java.util.Collection<V>>	map

Constructor Summary

Constructors

Constructor and Description
Multimap()
Multimap(java.lang.Class<? extends java.util.Map> mapClass, java.lang.Class<? extends java.util.Collection<V>> collectionClass)

Method Summary

Modifier and Type	Method and Description
boolean	containsKey(K key)
void	forEach(java.util.function.BiConsumer<? super K,? super java.util.Collection<V>> action)
@Nullable java.util.Collection<V>	get(K key) Return possibly empty collection of elements associated with a given key.
V	getFirst(K key)
@NonNull java.util.List<V>	getList(K key) Return all associated element as a list, possibly empty.
@NonNull java.util.Set<K>	keySet()
static <T,U> Multimap	newInstance()
void	put(K key, V value)
<C extends java.util.Collection<V>> C	remove(K key) Remove all elements, if any existed, associated with a key.
boolean	removeValue(K key, V value) Remove a value it it was associated with a specified key
int	size()
@NonNull java.util.List<V>	values() Return all elements associated with all keys.

Methods inherited from class java.lang.Object

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

Field Detail

map

protected java.util.Map<K,java.util.Collection<V>> map

Constructor Detail

Multimap

public Multimap()

Multimap

public Multimap(java.lang.Class<? extends java.util.Map> mapClass,
                java.lang.Class<? extends java.util.Collection<V>> collectionClass)

Method Detail

newInstance

public static <T,U> Multimap newInstance()

size

public int size()

get

public @Nullable java.util.Collection<V> get(K key)

Return possibly empty collection of elements associated with a given key.

Parameters:

key -

Returns:

getFirst

public V getFirst(K key)

getList

public @NonNull java.util.List<V> getList(K key)

Return all associated element as a list, possibly empty.

Parameters:

key -

Returns:

forEach

public void forEach(java.util.function.BiConsumer<? super K,? super java.util.Collection<V>> action)

put

public void put(K key,
                V value)

remove

public <C extends java.util.Collection<V>> C remove(K key)

Remove all elements, if any existed, associated with a key.

Parameters:

key -

Returns:

collection of just removed elements or null if no elements were actually removed

removeValue

public boolean removeValue(K key,
                           V value)

Remove a value it it was associated with a specified key

Parameters:

key -

value -

Returns:

true if the value was actually removed

containsKey

public boolean containsKey(K key)

keySet

public @NonNull java.util.Set<K> keySet()

values

public @NonNull java.util.List<V> values()

Return all elements associated with all keys. Note, that if the same element is associated more than once, for example, in different keys, it will appear in the resulting list more than once. Construct a Set of it if needed.

Returns:

list of all elements