Package com.google.common.collect

Interface BiMap<K extends @Nullable Object,V extends @Nullable Object>

All Superinterfaces:

Map<K,V>

All Known Implementing Classes:

EnumBiMap, EnumHashBiMap, HashBiMap, ImmutableBiMap

@GwtCompatible
public interface BiMap<K extends @Nullable Object,V extends @Nullable Object>
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 reversed keys and values.

Implementations

• ImmutableBiMap
• HashBiMap
• EnumBiMap
• EnumHashBiMap

See the Guava User Guide article on BiMap.

Since:

2.0

Author:

Kevin Bourrillion

Nested Class Summary

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

Map.Entry<K extends Object,V extends Object>

Method Summary

Modifier and Type	Method	Description
@Nullable V	forcePut(K key, V value)	An alternate form of put that silently removes any existing entry with the value value 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.
@Nullable 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, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, putIfAbsent, remove, remove, replace, replace, replaceAll, size

Method Detail

put

@CanIgnoreReturnValue
@Nullable V put(K key,
                V value)

Specified by:

put in interface Map<K extends @Nullable Object,V extends @Nullable Object>

Throws:

IllegalArgumentException - if the given value is already bound to a different key in this bimap. The bimap will remain unmodified in this event. To avoid this exception, call forcePut(K, V) instead.

forcePut

@CanIgnoreReturnValue
@Nullable V forcePut(K key,
                     V value)

An alternate form of put that silently removes any existing entry with the value value before proceeding with the put(K, V) operation. If the bimap previously contained the provided key-value mapping, this method has no effect.

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 that 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 that was previously associated with the key, or null if there was no previous entry. (If the bimap contains null values, then forcePut, like put, returns null both if the key is absent and if it is present with a null value.)

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 extends @Nullable Object,V extends @Nullable Object>

Throws:

IllegalArgumentException - if an attempt to put any entry fails. Note that some map entries may have been added to the bimap before the exception was thrown.

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 extends @Nullable Object,V extends @Nullable Object>

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