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com.google.common.collect
Class HashBiMap<K,V>

java.lang.Object
  extended by com.google.common.collect.ForwardingObject
      extended by com.google.common.collect.ForwardingMap<K,V>
          extended by com.google.common.collect.HashBiMap<K,V>
All Implemented Interfaces:
BiMap<K,V>, Serializable, Map<K,V>
@GwtCompatible(emulated=true)
public final class HashBiMap<K,V>
extends ForwardingMap<K,V>

A BiMap backed by two HashMap instances. This implementation allows null keys and values. A HashBiMap and its inverse are both serializable.

Since:
2 (imported from Google Collections Library)
Author:
Mike Bostock
See Also:
Serialized Form

Nested Class Summary
 
Nested classes/interfaces inherited from interface java.util.Map
Map.Entry<K,V>
 
Method Summary
 void clear()
          Removes all of the mappings from this map (optional operation).
 boolean containsValue(Object value)
          Returns true if this map maps one or more keys to the specified value.
static
<K,V> HashBiMap<K,V>
create()
          Returns a new, empty HashBiMap with the default initial capacity (16).
static
<K,V> HashBiMap<K,V>
create(int expectedSize)
          Constructs a new, empty bimap with the specified expected size.
static
<K,V> HashBiMap<K,V>
create(Map<? extends K,? extends V> map)
          Constructs a new bimap containing initial values from map.
protected  Map<K,V> delegate()
          Returns the backing delegate instance that methods are forwarded to.
 Set<Map.Entry<K,V>> entrySet()
          Returns a Set view of the mappings contained in this map.
 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 BiMap.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.
 Set<K> keySet()
          Returns a Set view of the keys contained in this map.
 V put(K key, V value)
          Associates the specified value with the specified key in this map (optional operation).
 void putAll(Map<? extends K,? extends V> map)
          Copies all of the mappings from the specified map to this map (optional operation).
 V remove(Object key)
          Removes the mapping for a key from this map if it is present (optional operation).
 Set<V> values()
          Returns a Collection view of the values contained in this map.
 
Methods inherited from class com.google.common.collect.ForwardingMap
containsKey, equals, get, hashCode, isEmpty, size, standardClear, standardContainsKey, standardContainsValue, standardEntrySet, standardEquals, standardHashCode, standardIsEmpty, standardKeySet, standardPutAll, standardRemove, standardToString, standardValues
 
Methods inherited from class com.google.common.collect.ForwardingObject
toString
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.util.Map
containsKey, equals, get, hashCode, isEmpty, size
 

Method Detail

create

public static <K,V> HashBiMap<K,V> create()
Returns a new, empty HashBiMap with the default initial capacity (16).

create

public static <K,V> HashBiMap<K,V> create(int expectedSize)
Constructs a new, empty bimap with the specified expected size.

Parameters:
expectedSize - the expected number of entries
Throws:
IllegalArgumentException - if the specified expected size is negative

create

public static <K,V> HashBiMap<K,V> create(Map<? extends K,? extends V> map)
Constructs a new bimap containing initial values from map. The bimap is created with an initial capacity sufficient to hold the mappings in the specified map.

put

public V put(@Nullable
             K key,
             @Nullable
             V value)
Description copied from interface: java.util.Map
Associates the specified value with the specified key in this map (optional operation). If the map previously contained a mapping for the key, the old value is replaced by the specified value. (A map m is said to contain a mapping for a key k if and only if m.containsKey(k) would return true.)

Specified by:
put in interface BiMap<K,V>
Specified by:
put in interface Map<K,V>
Parameters:
key - key with which the specified value is to be associated
value - value to be associated with the specified key
Returns:
the previous value associated with key, or null if there was no mapping for key. (A null return can also indicate that the map previously associated null with key, if the implementation supports null values.)

forcePut

public V forcePut(@Nullable
                  K key,
                  @Nullable
                  V value)
Description copied from interface: BiMap
An alternate form of put that silently removes any existing entry with the value value before proceeding with the BiMap.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.

Specified by:
forcePut in interface BiMap<K,V>
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

delegate

protected Map<K,V> delegate()
Description copied from class: ForwardingObject
Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such as ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.

Specified by:
delegate in class ForwardingMap<K,V>

containsValue

public boolean containsValue(Object value)
Description copied from interface: java.util.Map
Returns true if this map maps one or more keys to the specified value. More formally, returns true if and only if this map contains at least one mapping to a value v such that (value==null ? v==null : value.equals(v)). This operation will probably require time linear in the map size for most implementations of the Map interface.

Specified by:
containsValue in interface Map<K,V>
Overrides:
containsValue in class ForwardingMap<K,V>
Parameters:
value - value whose presence in this map is to be tested
Returns:
true if this map maps one or more keys to the specified value

remove

public V remove(Object key)
Description copied from interface: java.util.Map
Removes the mapping for a key from this map if it is present (optional operation). More formally, if this map contains a mapping from key k to value v such that (key==null ? k==null : key.equals(k)), that mapping is removed. (The map can contain at most one such mapping.)

Returns the value to which this map previously associated the key, or null if the map contained no mapping for the key.

If this map permits null values, then a return value of null does not necessarily indicate that the map contained no mapping for the key; it's also possible that the map explicitly mapped the key to null.

The map will not contain a mapping for the specified key once the call returns.

Specified by:
remove in interface Map<K,V>
Overrides:
remove in class ForwardingMap<K,V>
Parameters:
key - key whose mapping is to be removed from the map
Returns:
the previous value associated with key, or null if there was no mapping for key.

putAll

public void putAll(Map<? extends K,? extends V> map)
Description copied from interface: java.util.Map
Copies all of the mappings from the specified map to this map (optional operation). The effect of this call is equivalent to that of calling put(k, v) on this map once for each mapping from key k to value v in the specified map. The behavior of this operation is undefined if the specified map is modified while the operation is in progress.

Specified by:
putAll in interface BiMap<K,V>
Specified by:
putAll in interface Map<K,V>
Overrides:
putAll in class ForwardingMap<K,V>
Parameters:
map - mappings to be stored in this map

clear

public void clear()
Description copied from interface: java.util.Map
Removes all of the mappings from this map (optional operation). The map will be empty after this call returns.

Specified by:
clear in interface Map<K,V>
Overrides:
clear in class ForwardingMap<K,V>

inverse

public BiMap<V,K> inverse()
Description copied from interface: BiMap
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.

Specified by:
inverse in interface BiMap<K,V>
Returns:
the inverse view of this bimap

keySet

public Set<K> keySet()
Description copied from interface: java.util.Map
Returns a Set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The set 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:
keySet in interface Map<K,V>
Overrides:
keySet in class ForwardingMap<K,V>
Returns:
a set view of the keys contained in this map

values

public Set<V> values()
Description copied from interface: java.util.Map
Returns a Collection view of the values contained in this map. The collection 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, Collection.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.

Specified by:
values in interface BiMap<K,V>
Specified by:
values in interface Map<K,V>
Overrides:
values in class ForwardingMap<K,V>
Returns:
a collection view of the values contained in this map

entrySet

public Set<Map.Entry<K,V>> entrySet()
Description copied from interface: java.util.Map
Returns a Set view of the mappings contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation, or through the setValue operation on a map entry returned by the iterator) the results of the iteration are undefined. The set 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:
entrySet in interface Map<K,V>
Overrides:
entrySet in class ForwardingMap<K,V>
Returns:
a set view of the mappings contained in this map
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