org.apache.commons.collections.bidimap
Class AbstractBidiMapDecorator<K,V>

java.lang.Object
  org.apache.commons.collections.map.AbstractMapDecorator<K,V>
      org.apache.commons.collections.bidimap.AbstractBidiMapDecorator<K,V>

All Implemented Interfaces:

Map<K,V>, BidiMap<K,V>, IterableMap<K,V>

Direct Known Subclasses:

AbstractOrderedBidiMapDecorator, UnmodifiableBidiMap

public abstract class AbstractBidiMapDecorator<K,V>
extends AbstractMapDecorator<K,V>
implements BidiMap<K,V>

Provides a base decorator that enables additional functionality to be added to a BidiMap via decoration.

Methods are forwarded directly to the decorated map.

This implementation does not perform any special processing with the map views. Instead it simply returns the set/collection from the wrapped map. This may be undesirable, for example if you are trying to write a validating implementation it would provide a loophole around the validation. But, you might want that loophole, so this class is kept simple.

Since:

Commons Collections 3.0

Version:

$Revision: 1.1.1.1 $ $Date: 2005/05/23 04:33:36 $

Author:

Matt Hall, John Watkinson, Stephen Colebourne

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Field Summary

Fields inherited from class org.apache.commons.collections.map.AbstractMapDecorator

map

Constructor Summary

protected

AbstractBidiMapDecorator(BidiMap<K,V> map) Constructor that wraps (not copies).

Method Summary

protected BidiMap<K,V>	getBidiMap() Gets the map being decorated.
K	getKey(V value) Gets the key that is currently mapped to the specified value.
BidiMap<V,K>	inverseBidiMap() Gets a view of this map where the keys and values are reversed.
MapIterator<K,V>	mapIterator() Obtains a MapIterator over the map.
K	removeValue(V value) Removes the key-value pair that is currently mapped to the specified value (optional operation).

Methods inherited from class org.apache.commons.collections.map.AbstractMapDecorator

clear, containsKey, containsValue, entrySet, equals, get, getMap, hashCode, isEmpty, keySet, put, putAll, remove, 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.collections.BidiMap

put

Methods inherited from interface java.util.Map

clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, putAll, remove, size, values

Constructor Detail

AbstractBidiMapDecorator

protected AbstractBidiMapDecorator(BidiMap<K,V> map)

Constructor that wraps (not copies).

Parameters:

map - the map to decorate, must not be null

Throws:

IllegalArgumentException - if the collection is null

Method Detail

getBidiMap

protected BidiMap<K,V> getBidiMap()

Gets the map being decorated.

Returns:

the decorated map

mapIterator

public MapIterator<K,V> mapIterator()

Description copied from interface: BidiMap

Obtains a MapIterator over the map.

A map iterator is an efficient way of iterating over maps. It does not require that the map is stored using Map Entry objects which can increase performance.

 BidiMap map = new DualHashBidiMap();
 MapIterator it = map.mapIterator();
 while (it.hasNext()) {
   Object key = it.next();
   Object value = it.getValue();
   it.setValue("newValue");
 }
 

Specified by:

mapIterator in interface BidiMap<K,V>

Specified by:

mapIterator in interface IterableMap<K,V>

Returns:

a map iterator

getKey

public K getKey(V value)

Description copied from interface: BidiMap

Gets the key that is currently mapped to the specified value.

If the value is not contained in the map, null is returned.

Implementations should seek to make this method perform equally as well as get(Object).

Specified by:

getKey in interface BidiMap<K,V>

Parameters:

value - the value to find the key for

Returns:

the mapped key, or null if not found

removeValue

public K removeValue(V value)

Description copied from interface: BidiMap

Removes the key-value pair that is currently mapped to the specified value (optional operation).

If the value is not contained in the map, null is returned.

Implementations should seek to make this method perform equally as well as remove(Object).

Specified by:

removeValue in interface BidiMap<K,V>

Parameters:

value - the value to find the key-value pair for

Returns:

the key that was removed, null if nothing removed

inverseBidiMap

public BidiMap<V,K> inverseBidiMap()

Description copied from interface: BidiMap

Gets a view of this map where the keys and values are reversed.

Changes to one map will be visible in the other and vice versa. This enables both directions of the map to be accessed as a Map.

Implementations should seek to avoid creating a new object every time this method is called. See AbstractMap.values() etc. Calling this method on the inverse map should return the original.

Specified by:

inverseBidiMap in interface BidiMap<K,V>

Returns:

an inverted bidirectional map