Package org.apache.commons.collections4.multimap

Class AbstractListValuedMap<K,V>

java.lang.Object

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

org.apache.commons.collections4.multimap.AbstractListValuedMap<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:

ListValuedMap<K,V>, MultiValuedMap<K,V>

Direct Known Subclasses:

ArrayListValuedHashMap

public abstract class AbstractListValuedMap<K,V>
extends AbstractMultiValuedMap<K,V>
implements ListValuedMap<K,V>

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

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

Since:

4.1

Constructor Summary

Constructors

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

Method Summary

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

AbstractListValuedMap

protected AbstractListValuedMap()

Constructor needed for subclass serialisation.

AbstractListValuedMap

protected AbstractListValuedMap(Map<K,? extends List<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 List<V> createCollection()

Creates a new value collection using the provided factory.

Specified by:

createCollection in class AbstractMultiValuedMap<K,V>

Returns:

a new list

get

public List<V> get(K key)

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

Specified by:

get in interface ListValuedMap<K,V>

Specified by:

get in interface MultiValuedMap<K,V>

Overrides:

get in class AbstractMultiValuedMap<K,V>

Parameters:

key - the key to retrieve

Returns:

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

getMap

protected Map<K,List<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 List<V> remove(Object key)

Removes all values associated with the specified key.

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

Specified by:

remove in interface ListValuedMap<K,V>

Specified by:

remove in interface MultiValuedMap<K,V>

Overrides:

remove in class AbstractMultiValuedMap<K,V>

Parameters:

key - the key to remove values from

Returns:

the List of values removed, will return an empty, unmodifiable list for no mapping found.