Package org.apache.commons.collections4.bidimap

Class DualTreeBidiMap<K,V>

java.lang.Object

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

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

Type Parameters:

K - the type of the keys in this map

V - the type of the values in this map

All Implemented Interfaces:

Serializable, Map<K,V>, SortedMap<K,V>, BidiMap<K,V>, Get<K,V>, IterableGet<K,V>, IterableMap<K,V>, OrderedBidiMap<K,V>, OrderedMap<K,V>, Put<K,V>, SortedBidiMap<K,V>

public class DualTreeBidiMap<K,V>
extends AbstractDualBidiMap<K,V>
implements SortedBidiMap<K,V>, Serializable

Implementation of BidiMap that uses two TreeMap instances.

The setValue() method on iterators will succeed only if the new value being set is not already in the bidi map.

When considering whether to use this class, the TreeBidiMap class should also be considered. It implements the interface using a dedicated design, and does not store each object twice, which can save on memory use.

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

Since:

3.0

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	DualTreeBidiMap.BidiOrderedMapIterator<K,V>	Inner class MapIterator.
protected static class	DualTreeBidiMap.ViewMap<K,V>	Internal sorted map view.

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 extends Object,V extends Object>

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
Comparator<? super K>	comparator()
protected DualTreeBidiMap<V,K>	createBidiMap(Map<V,K> normalMap, Map<K,V> reverseMap, BidiMap<K,V> inverseMap)	Creates a new instance of this object.
K	firstKey()	Gets the first key currently in this map.
SortedMap<K,V>	headMap(K toKey)
SortedBidiMap<V,K>	inverseBidiMap()	Gets a view of this map where the keys and values are reversed.
OrderedBidiMap<V,K>	inverseOrderedBidiMap()
SortedBidiMap<V,K>	inverseSortedBidiMap()
K	lastKey()	Gets the last key currently in this map.
OrderedMapIterator<K,V>	mapIterator()	Obtains an ordered map iterator.
K	nextKey(K key)	Gets the next key after the one specified.
K	previousKey(K key)	Gets the previous key before the one specified.
SortedMap<K,V>	subMap(K fromKey, K toKey)
SortedMap<K,V>	tailMap(K fromKey)
Comparator<? super V>	valueComparator()	Gets the comparator used for the values in the value-to-key map aspect.

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

clear, containsKey, containsValue, createEntrySetIterator, createKeySetIterator, createValuesIterator, entrySet, equals, get, getKey, hashCode, isEmpty, keySet, 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 org.apache.commons.collections4.BidiMap

getKey, put, removeValue, values

Methods inherited from interface org.apache.commons.collections4.Get

containsKey, containsValue, entrySet, get, isEmpty, keySet, remove, size, values

Methods inherited from interface java.util.Map

clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, equals, forEach, get, getOrDefault, hashCode, isEmpty, merge, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size

Methods inherited from interface org.apache.commons.collections4.Put

clear, put, putAll

Methods inherited from interface java.util.SortedMap

entrySet, keySet, values

Constructor Details

DualTreeBidiMap

public DualTreeBidiMap()

Creates an empty DualTreeBidiMap.

DualTreeBidiMap

public DualTreeBidiMap(Comparator<? super K> keyComparator,
 Comparator<? super V> valueComparator)

Constructs a DualTreeBidiMap using the specified Comparator.

Parameters:

keyComparator - the comparator

valueComparator - the values comparator to use

DualTreeBidiMap

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

Constructs a DualTreeBidiMap and copies the mappings from specified Map.

Parameters:

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

DualTreeBidiMap

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

Constructs a DualTreeBidiMap that decorates the specified maps.

Parameters:

normalMap - the normal direction map

reverseMap - the reverse direction map

inverseBidiMap - the inverse BidiMap

Method Details

comparator

public Comparator<? super K> comparator()

Specified by:

comparator in interface SortedMap<K,V>

createBidiMap

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

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

inverseMap - the inverse BidiMap

Returns:

new bidi map

firstKey

public K firstKey()

Description copied from interface: OrderedMap

Gets the first key currently in this map.

Specified by:

firstKey in interface OrderedMap<K,V>

Specified by:

firstKey in interface SortedMap<K,V>

Returns:

the first key currently in this map

headMap

public SortedMap<K,V> headMap(K toKey)

Specified by:

headMap in interface SortedMap<K,V>

inverseBidiMap

public SortedBidiMap<V,K> inverseBidiMap()

Description copied from interface: BidiMap

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.

Specified by:

inverseBidiMap in interface BidiMap<K,V>

Specified by:

inverseBidiMap in interface OrderedBidiMap<K,V>

Specified by:

inverseBidiMap in interface SortedBidiMap<K,V>

Overrides:

inverseBidiMap in class AbstractDualBidiMap<K,V>

Returns:

an inverted bidirectional map

inverseOrderedBidiMap

public OrderedBidiMap<V,K> inverseOrderedBidiMap()

inverseSortedBidiMap

public SortedBidiMap<V,K> inverseSortedBidiMap()

lastKey

public K lastKey()

Description copied from interface: OrderedMap

Gets the last key currently in this map.

Specified by:

lastKey in interface OrderedMap<K,V>

Specified by:

lastKey in interface SortedMap<K,V>

Returns:

the last key currently in this map

mapIterator

public OrderedMapIterator<K,V> mapIterator()

Obtains an ordered map iterator.

This implementation copies the elements to an ArrayList in order to provide the forward/backward behavior.

Specified by:

mapIterator in interface IterableGet<K,V>

Specified by:

mapIterator in interface OrderedMap<K,V>

Overrides:

mapIterator in class AbstractDualBidiMap<K,V>

Returns:

a new ordered map iterator

nextKey

public K nextKey(K key)

Description copied from interface: OrderedMap

Gets the next key after the one specified.

Specified by:

nextKey in interface OrderedMap<K,V>

Parameters:

key - the key to search for next from

Returns:

the next key, null if no match or at end

previousKey

public K previousKey(K key)

Description copied from interface: OrderedMap

Gets the previous key before the one specified.

Specified by:

previousKey in interface OrderedMap<K,V>

Parameters:

key - the key to search for previous from

Returns:

the previous key, null if no match or at start

subMap

public SortedMap<K,V> subMap(K fromKey,
 K toKey)

Specified by:

subMap in interface SortedMap<K,V>

tailMap

public SortedMap<K,V> tailMap(K fromKey)

Specified by:

tailMap in interface SortedMap<K,V>

valueComparator

public Comparator<? super V> valueComparator()

Description copied from interface: SortedBidiMap

Gets the comparator used for the values in the value-to-key map aspect.

Specified by:

valueComparator in interface SortedBidiMap<K,V>

Returns:

Comparator<? super V>