org.apache.commons.collections.bidimap
Class AbstractDualBidiMap

java.lang.Object
  |
  +--org.apache.commons.collections.bidimap.AbstractDualBidiMap

All Implemented Interfaces:

BidiMap, IterableMap, java.util.Map

Direct Known Subclasses:

DualHashBidiMap, DualTreeBidiMap

public abstract class AbstractDualBidiMap

extends java.lang.Object

implements BidiMap

Abstract BidiMap implemented using two maps.

An implementation can be written simply by implementing the createMap method.

Since:

Commons Collections 3.0

Version:

$Id: AbstractDualBidiMap.java,v 1.14 2004/06/22 21:54:35 scolebourne Exp $

Author:

Matthew Hawthorne, Stephen Colebourne

See Also:

DualHashBidiMap, DualTreeBidiMap

Method Summary

void	clear()
boolean	containsKey(java.lang.Object key)
boolean	containsValue(java.lang.Object value)
java.util.Set	entrySet() Gets an entrySet view of the map.
boolean	equals(java.lang.Object obj)
java.lang.Object	get(java.lang.Object key)
java.lang.Object	getKey(java.lang.Object value) Gets the key that is currently mapped to the specified value.
int	hashCode()
BidiMap	inverseBidiMap() Gets a view of this map where the keys and values are reversed.
boolean	isEmpty()
java.util.Set	keySet() Gets a keySet view of the map.
MapIterator	mapIterator() Obtains a MapIterator over the map.
java.lang.Object	put(java.lang.Object key, java.lang.Object value) Puts the key-value pair into the map, replacing any previous pair.
void	putAll(java.util.Map map)
java.lang.Object	remove(java.lang.Object key)
java.lang.Object	removeValue(java.lang.Object value) Removes the key-value pair that is currently mapped to the specified value (optional operation).
int	size()
java.lang.String	toString()
java.util.Collection	values() Gets a values view of the map.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Method Detail

get

public java.lang.Object get(java.lang.Object key)

Specified by:

get in interface java.util.Map

size

public int size()

Specified by:

size in interface java.util.Map

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Map

containsKey

public boolean containsKey(java.lang.Object key)

Specified by:

containsKey in interface java.util.Map

equals

public boolean equals(java.lang.Object obj)

Specified by:

equals in interface java.util.Map

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Map

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

put

public java.lang.Object put(java.lang.Object key,
                            java.lang.Object value)

Description copied from interface: BidiMap

Puts the key-value pair into the map, replacing any previous pair.

When adding a key-value pair, the value may already exist in the map against a different key. That mapping is removed, to ensure that the value only occurs once in the inverse map.

  BidiMap map1 = new DualHashBidiMap();
  map.put("A","B");  // contains A mapped to B, as per Map
  map.put("A","C");  // contains A mapped to C, as per Map
 
  BidiMap map2 = new DualHashBidiMap();
  map.put("A","B");  // contains A mapped to B, as per Map
  map.put("C","B");  // contains C mapped to B, key A is removed
 

Specified by:

put in interface BidiMap

Parameters:

key - the key to store

value - the value to store

Returns:

the previous value mapped to this key

putAll

public void putAll(java.util.Map map)

Specified by:

putAll in interface java.util.Map

remove

public java.lang.Object remove(java.lang.Object key)

Specified by:

remove in interface java.util.Map

clear

public void clear()

Specified by:

clear in interface java.util.Map

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

containsValue in interface java.util.Map

mapIterator

public MapIterator mapIterator()

Obtains a MapIterator over the map. The iterator implements ResetableMapIterator. This implementation relies on the entrySet iterator.

The setValue() methods only allow a new value to be set. If the value being set is already in the map, an IllegalArgumentException is thrown (as setValue cannot change the size of the map).

Specified by:

mapIterator in interface BidiMap

Returns:

a map iterator

getKey

public java.lang.Object getKey(java.lang.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

Parameters:

value - the value to find the key for

Returns:

the mapped key, or null if not found

removeValue

public java.lang.Object removeValue(java.lang.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

Parameters:

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

Returns:

the key that was removed, null if nothing removed

inverseBidiMap

public BidiMap 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

Returns:

an inverted bidirectional map

keySet

public java.util.Set keySet()

Gets a keySet view of the map. Changes made on the view are reflected in the map. The set supports remove and clear but not add.

Specified by:

keySet in interface java.util.Map

Returns:

the keySet view

values

public java.util.Collection values()

Gets a values view of the map. Changes made on the view are reflected in the map. The set supports remove and clear but not add.

Specified by:

values in interface java.util.Map

Returns:

the values view

entrySet

public java.util.Set entrySet()

Gets an entrySet view of the map. Changes made on the set are reflected in the map. The set supports remove and clear but not add.

The Map Entry setValue() method only allow a new value to be set. If the value being set is already in the map, an IllegalArgumentException is thrown (as setValue cannot change the size of the map).

Specified by:

entrySet in interface java.util.Map

Returns:

the entrySet view