org.apache.commons.collections15.bidimap
Class AbstractBidiMapDecorator<K,V>

java.lang.Object
  extended by org.apache.commons.collections15.map.AbstractMapDecorator<K,V>
      extended by org.apache.commons.collections15.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 $ $Date: 2005/10/11 17:05:19 $
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.collections15.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(Object 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(Object value)
          Removes the key-value pair that is currently mapped to the specified value (optional operation).
 Set<V> values()
          Returns a set view of the values contained in this BidiMap.
 
Methods inherited from class org.apache.commons.collections15.map.AbstractMapDecorator
clear, containsKey, containsValue, entrySet, equals, get, getMap, hashCode, isEmpty, keySet, put, putAll, remove, size, toString
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.apache.commons.collections15.BidiMap
put
 
Methods inherited from interface java.util.Map
clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, putAll, remove, size
 

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(Object 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(Object 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

values

public Set<V> values()
Description copied from interface: BidiMap
Returns a set view of the values contained in this BidiMap. The set is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.

Specified by:
values in interface Map<K,V>
Specified by:
values in interface BidiMap<K,V>
Overrides:
values in class AbstractMapDecorator<K,V>
Returns:
a Set view of the values contained in this map.


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