Package org.apache.commons.collections4.bidimap

Class DualHashBidiMap<K,V>

java.lang.Object

org.apache.commons.collections4.bidimap.AbstractDualBidiMap<K,V>

org.apache.commons.collections4.bidimap.DualHashBidiMap<K,V>

Type Parameters:

K - the type of the keys in the map

V - the type of the values in the map

All Implemented Interfaces:

Serializable, Map<K,V>, BidiMap<K,V>, Get<K,V>, IterableGet<K,V>, IterableMap<K,V>, Put<K,V>

public class DualHashBidiMap<K,V>
extends AbstractDualBidiMap<K,V>
implements Serializable

Implements BidiMap with two HashMap instances.

Two HashMap instances are used in this class. This provides fast lookups at the expense of storing two sets of map entries. Commons Collections would welcome the addition of a direct hash-based implementation of the BidiMap interface.

NOTE: From Commons Collections 3.1, all subclasses will use HashMap and the flawed createMap method is ignored.

Since:

3.0

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.commons.collections4.bidimap.AbstractDualBidiMap

AbstractDualBidiMap.BidiMapIterator<K,V>, AbstractDualBidiMap.EntrySet<K,V>, AbstractDualBidiMap.EntrySetIterator<K,V>, AbstractDualBidiMap.KeySet<K>, AbstractDualBidiMap.KeySetIterator<K>, AbstractDualBidiMap.MapEntry<K,V>, AbstractDualBidiMap.Values<V>, AbstractDualBidiMap.ValuesIterator<V>, AbstractDualBidiMap.View<K,V,E>

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

Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field	Description
private static final long	serialVersionUID	Ensure serialization compatibility

Fields inherited from class org.apache.commons.collections4.bidimap.AbstractDualBidiMap

entrySet, inverseBidiMap, keySet, normalMap, reverseMap, values

Constructor Summary

Constructors

Modifier	Constructor	Description
	DualHashBidiMap()	Creates an empty HashBidiMap.
	DualHashBidiMap(Map<? extends K,? extends V> map)	Constructs a HashBidiMap and copies the mappings from specified Map.
protected	DualHashBidiMap(Map<K,V> normalMap, Map<V,K> reverseMap, BidiMap<V,K> inverseBidiMap)	Constructs a HashBidiMap that decorates the specified maps.

Method Summary

Modifier and Type	Method	Description
protected BidiMap<V,K>	createBidiMap(Map<V,K> normalMap, Map<K,V> reverseMap, BidiMap<K,V> inverseBidiMap)	Creates a new instance of this object.
private void	readObject(ObjectInputStream in)	Deserializes an instance from an ObjectInputStream.
private void	writeObject(ObjectOutputStream out)	Serializes this object to an ObjectOutputStream.

Methods inherited from class org.apache.commons.collections4.bidimap.AbstractDualBidiMap

clear, containsKey, containsValue, createEntrySetIterator, createKeySetIterator, createValuesIterator, entrySet, equals, get, getKey, hashCode, inverseBidiMap, isEmpty, keySet, mapIterator, put, putAll, remove, removeValue, size, toString, values

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Field Details

serialVersionUID

private static final long serialVersionUID

Ensure serialization compatibility

See Also:

• Constant Field Values

Constructor Details

DualHashBidiMap

public DualHashBidiMap()

Creates an empty HashBidiMap.

DualHashBidiMap

public DualHashBidiMap(Map<? extends K,? extends V> map)

Constructs a HashBidiMap and copies the mappings from specified Map.

Parameters:

map - the map whose mappings are to be placed in this map

DualHashBidiMap

protected DualHashBidiMap(Map<K,V> normalMap,
 Map<V,K> reverseMap,
 BidiMap<V,K> inverseBidiMap)

Constructs a HashBidiMap that decorates the specified maps.

Parameters:

normalMap - the normal direction map

reverseMap - the reverse direction map

inverseBidiMap - the inverse BidiMap

Method Details

createBidiMap

protected BidiMap<V,K> createBidiMap(Map<V,K> normalMap,
 Map<K,V> reverseMap,
 BidiMap<K,V> inverseBidiMap)

Creates a new instance of this object.

Specified by:

createBidiMap in class AbstractDualBidiMap<K,V>

Parameters:

normalMap - the normal direction map

reverseMap - the reverse direction map

inverseBidiMap - the inverse BidiMap

Returns:

new bidi map

readObject

private void readObject(ObjectInputStream in)
                 throws IOException,
ClassNotFoundException

Deserializes an instance from an ObjectInputStream.

Parameters:

in - The source ObjectInputStream.

Throws:

IOException - Any of the usual Input/Output related exceptions.

ClassNotFoundException - A class of a serialized object cannot be found.

writeObject

private void writeObject(ObjectOutputStream out)
                  throws IOException

Serializes this object to an ObjectOutputStream.

Parameters:

out - the target ObjectOutputStream.

Throws:

IOException - thrown when an I/O errors occur writing to the target stream.