com.google.common.collect
Interface BiMap<K,V>

All Superinterfaces:

Map<K,V>

All Known Implementing Classes:

EnumBiMap, EnumHashBiMap, HashBiMap

public interface BiMap<K,V>
extends Map<K,V>

A bimap (or "bidirectional map") is a map that preserves the uniqueness of its values as well as that of its keys. This constraint enables bimaps to support an "inverse view", which is another bimap containing the same entries as this bimap but with its keys and values reversed.

Author:

Kevin Bourrillion

Nested Class Summary

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

Map.Entry<K,V>

Method Summary

V	forcePut(K key, V value) An alternate form of put which silently removes any existing entry with the value value (unless it is already matched with the key key) before proceeding with the put(K, V) operation.
BiMap<V,K>	inverse() Returns the inverse view of this bimap, which maps each of this bimap's values to its associated key.
V	put(K key, V value)
void	putAll(Map<? extends K,? extends V> map)
Set<V>	values()

Methods inherited from interface java.util.Map

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

Method Detail

put

V put(K key,
      V value)

Specified by:

put in interface Map<K,V>

Throws:

IllegalArgumentException - if the given value is already bound to a different key in this bimap. The bimap will remain unmodified in this event.

forcePut

V forcePut(K key,
           V value)

An alternate form of put which silently removes any existing entry with the value value (unless it is already matched with the key key) before proceeding with the put(K, V) operation. Note that a successful call to this method could cause the size of the bimap to increase by one, stay the same, or even decrease by one.

Warning: If an existing entry with this value is removed, the key for this entry is discarded and not returned.

Parameters:

key - the key with which the specified value is to be associated

value - the value to be associated with the specified key

Returns:

the value which was previously associated with the key, which may be null, or null if there was no previous entry

putAll

void putAll(Map<? extends K,? extends V> map)

Warning: the results of calling this method may vary depending on the iteration order of map!

Specified by:

putAll in interface Map<K,V>

Throws:

IllegalArgumentException - if an attempt to put any particular entry fails. Warning: the bimap may be left with an indeterminate number of entries from map having been added.

values

Set<V> values()

Because a bimap has unique values, this method returns a Set, instead of the Collection specified in the Map interface.

Specified by:

values in interface Map<K,V>

inverse

BiMap<V,K> inverse()

Returns the inverse view of this bimap, which maps each of this bimap's values to its associated key. The two bimaps are backed by the same data; any changes to one will appear in the other.

Note:There is no guaranteed correspondence between the iteration order of a bimap and that of its inverse.

Returns:

the inverse view of this bimap