Package org.apache.commons.collections4.multimap

Class AbstractSetValuedMap<K,V>

java.lang.Object

org.apache.commons.collections4.multimap.AbstractMultiValuedMap<K,V>

org.apache.commons.collections4.multimap.AbstractSetValuedMap<K,V>

Type Parameters:

K - the type of the keys in this map

V - the type of the values in this map

All Implemented Interfaces:

MultiValuedMap<K,V>, SetValuedMap<K,V>

Direct Known Subclasses:

HashSetValuedHashMap, LinkedHashSetValuedLinkedHashMap

public abstract class AbstractSetValuedMap<K,V>
extends AbstractMultiValuedMap<K,V>
implements SetValuedMap<K,V>

Abstract implementation of the SetValuedMap interface to simplify the creation of subclass implementations.

Subclasses specify a Map implementation to use as the internal storage and the Set implementation to use as values.

Since:

4.1

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractSetValuedMap()	Constructor needed for subclass serialisation.
protected	AbstractSetValuedMap(Map<K,? extends Set<V>> map)	A constructor that wraps, not copies

Method Summary

Modifier and Type	Method	Description
protected abstract Set<V>	createCollection()	Creates a new value collection using the provided factory.
Set<V>	get(K key)	Gets the set of values associated with the specified key.
protected Map<K,Set<V>>	getMap()	Gets the map being wrapped.
Set<V>	remove(Object key)	Removes all values associated with the specified key.

Methods inherited from class org.apache.commons.collections4.multimap.AbstractMultiValuedMap

asMap, clear, containsKey, containsMapping, containsValue, doReadObject, doWriteObject, entries, equals, hashCode, isEmpty, keys, keySet, mapIterator, put, putAll, putAll, putAll, removeMapping, setMap, size, toString, values

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.commons.collections4.MultiValuedMap

asMap, clear, containsKey, containsMapping, containsValue, entries, isEmpty, keys, keySet, mapIterator, put, putAll, putAll, putAll, removeMapping, size, values

Constructor Details

AbstractSetValuedMap

protected AbstractSetValuedMap()

Constructor needed for subclass serialisation.

AbstractSetValuedMap

protected AbstractSetValuedMap(Map<K,? extends Set<V>> map)

A constructor that wraps, not copies

Parameters:

map - the map to wrap, must not be null

Throws:

NullPointerException - if the map is null

Method Details

createCollection

protected abstract Set<V> createCollection()

Creates a new value collection using the provided factory.

Specified by:

createCollection in class AbstractMultiValuedMap<K,V>

Returns:

a new set

get

public Set<V> get(K key)

Gets the set of values associated with the specified key. This would return an empty set in case the mapping is not present

Specified by:

get in interface MultiValuedMap<K,V>

Specified by:

get in interface SetValuedMap<K,V>

Overrides:

get in class AbstractMultiValuedMap<K,V>

Parameters:

key - the key to retrieve

Returns:

the Set of values, will return an empty Set for no mapping

getMap

protected Map<K,Set<V>> getMap()

Description copied from class: AbstractMultiValuedMap

Gets the map being wrapped.

Overrides:

getMap in class AbstractMultiValuedMap<K,V>

Returns:

the wrapped map

remove

public Set<V> remove(Object key)

Removes all values associated with the specified key.

A subsequent get(Object) would return an empty set.

Specified by:

remove in interface MultiValuedMap<K,V>

Specified by:

remove in interface SetValuedMap<K,V>

Overrides:

remove in class AbstractMultiValuedMap<K,V>

Parameters:

key - the key to remove values from

Returns:

the Set of values removed, will return an empty, unmodifiable set for no mapping found.