Interface BidiMap
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- All Superinterfaces:
IterableMap
,Map
- All Known Subinterfaces:
OrderedBidiMap
,SortedBidiMap
- All Known Implementing Classes:
AbstractBidiMapDecorator
,AbstractDualBidiMap
,AbstractOrderedBidiMapDecorator
,AbstractSortedBidiMapDecorator
,DualHashBidiMap
,DualTreeBidiMap
,TreeBidiMap
,UnmodifiableBidiMap
,UnmodifiableOrderedBidiMap
,UnmodifiableSortedBidiMap
@Deprecated(since="2021-04-30") public interface BidiMap extends IterableMap
Deprecated.Commons Collections 3 is in maintenance mode. Commons Collections 4 should be used instead.Defines a map that allows bidirectional lookup between key and values.This extended
Map
represents a mapping where a key may lookup a value and a value may lookup a key with equal ease. This interface extendsMap
and so may be used anywhere a map is required. The interface provides an inverse map view, enabling full access to both directions of theBidiMap
.Implementations should allow a value to be looked up from a key and a key to be looked up from a value with equal performance.
This map enforces the restriction that there is a 1:1 relation between keys and values, meaning that multiple keys cannot map to the same value. This is required so that "inverting" the map results in a map without duplicate keys. See the
put(java.lang.Object, java.lang.Object)
method description for more information.- Since:
- Commons Collections 3.0
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Method Summary
All Methods Instance Methods Abstract Methods Deprecated Methods Modifier and Type Method Description Object
getKey(Object value)
Deprecated.Gets the key that is currently mapped to the specified value.BidiMap
inverseBidiMap()
Deprecated.Gets a view of this map where the keys and values are reversed.MapIterator
mapIterator()
Deprecated.Obtains aMapIterator
over the map.Object
put(Object key, Object value)
Deprecated.Puts the key-value pair into the map, replacing any previous pair.Object
removeValue(Object value)
Deprecated.Removes the key-value pair that is currently mapped to the specified value (optional operation).-
Methods inherited from interface java.util.Map
clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values
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Method Detail
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mapIterator
MapIterator mapIterator()
Deprecated.Obtains aMapIterator
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 interfaceIterableMap
- Returns:
- a map iterator
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put
Object put(Object key, Object value)
Deprecated.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 interfaceMap
- Parameters:
key
- the key to storevalue
- the value to store- Returns:
- the previous value mapped to this key
- Throws:
UnsupportedOperationException
- if theput
method is not supportedClassCastException
- (optional) if the map limits the type of the value and the specified value is inappropriateIllegalArgumentException
- (optional) if the map limits the values in some way and the value was invalidNullPointerException
- (optional) if the map limits the values to non-null and null was specified
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getKey
Object getKey(Object value)
Deprecated.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)
.- Parameters:
value
- the value to find the key for- Returns:
- the mapped key, or
null
if not found - Throws:
ClassCastException
- (optional) if the map limits the type of the value and the specified value is inappropriateNullPointerException
- (optional) if the map limits the values to non-null and null was specified
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removeValue
Object removeValue(Object value)
Deprecated.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)
.- Parameters:
value
- the value to find the key-value pair for- Returns:
- the key that was removed,
null
if nothing removed - Throws:
ClassCastException
- (optional) if the map limits the type of the value and the specified value is inappropriateNullPointerException
- (optional) if the map limits the values to non-null and null was specifiedUnsupportedOperationException
- if this method is not supported by the implementation
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inverseBidiMap
BidiMap inverseBidiMap()
Deprecated.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.- Returns:
- an inverted bidirectional map
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