org.apache.commons.collections.bidimap

Class DualTreeBidiMap

java.lang.Object

org.apache.commons.collections.bidimap.AbstractDualBidiMap

org.apache.commons.collections.bidimap.DualTreeBidiMap

All Implemented Interfaces:

java.io.Serializable, java.util.Map, java.util.SortedMap, BidiMap, IterableMap, OrderedBidiMap, OrderedMap, SortedBidiMap

public class DualTreeBidiMap
extends AbstractDualBidiMap
implements SortedBidiMap, java.io.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 bidimap.

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:

Commons Collections 3.0

See Also:

Serialized Form

Nested Class Summary

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

java.util.Map.Entry<K,V>

Constructor Summary

Constructors

Constructor and Description
DualTreeBidiMap() Creates an empty DualTreeBidiMap
DualTreeBidiMap(java.util.Comparator comparator) Constructs a DualTreeBidiMap using the specified Comparator.
DualTreeBidiMap(java.util.Map map) Constructs a DualTreeBidiMap and copies the mappings from specified Map.

Method Summary

Modifier and Type	Method and Description
java.util.Comparator	comparator()
java.lang.Object	firstKey() Gets the first key currently in this map.
java.util.SortedMap	headMap(java.lang.Object toKey)
OrderedBidiMap	inverseOrderedBidiMap() Gets a view of this map where the keys and values are reversed.
SortedBidiMap	inverseSortedBidiMap() Gets a view of this map where the keys and values are reversed.
java.lang.Object	lastKey() Gets the last key currently in this map.
java.lang.Object	nextKey(java.lang.Object key) Gets the next key after the one specified.
OrderedMapIterator	orderedMapIterator() Obtains an ordered map iterator.
java.lang.Object	previousKey(java.lang.Object key) Gets the previous key before the one specified.
java.util.SortedMap	subMap(java.lang.Object fromKey, java.lang.Object toKey)
java.util.SortedMap	tailMap(java.lang.Object fromKey)

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

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

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.commons.collections.SortedBidiMap

inverseBidiMap

Methods inherited from interface org.apache.commons.collections.BidiMap

getKey, mapIterator, put, removeValue

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

Methods inherited from interface java.util.SortedMap

entrySet, keySet, values

Constructor Detail

DualTreeBidiMap

public DualTreeBidiMap()

Creates an empty DualTreeBidiMap

DualTreeBidiMap

public DualTreeBidiMap(java.util.Map 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

public DualTreeBidiMap(java.util.Comparator comparator)

Constructs a DualTreeBidiMap using the specified Comparator.

Parameters:

comparator - the Comparator

Method Detail

comparator

public java.util.Comparator comparator()

Specified by:

comparator in interface java.util.SortedMap

firstKey

public java.lang.Object firstKey()

Description copied from interface: OrderedMap

Gets the first key currently in this map.

Specified by:

firstKey in interface java.util.SortedMap

Specified by:

firstKey in interface OrderedMap

Returns:

the first key currently in this map

lastKey

public java.lang.Object lastKey()

Description copied from interface: OrderedMap

Gets the last key currently in this map.

Specified by:

lastKey in interface java.util.SortedMap

Specified by:

lastKey in interface OrderedMap

Returns:

the last key currently in this map

nextKey

public java.lang.Object nextKey(java.lang.Object key)

Description copied from interface: OrderedMap

Gets the next key after the one specified.

Specified by:

nextKey in interface OrderedMap

Parameters:

key - the key to search for next from

Returns:

the next key, null if no match or at end

previousKey

public java.lang.Object previousKey(java.lang.Object key)

Description copied from interface: OrderedMap

Gets the previous key before the one specified.

Specified by:

previousKey in interface OrderedMap

Parameters:

key - the key to search for previous from

Returns:

the previous key, null if no match or at start

orderedMapIterator

public OrderedMapIterator orderedMapIterator()

Obtains an ordered map iterator.

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

Specified by:

orderedMapIterator in interface OrderedMap

Returns:

a new ordered map iterator

inverseSortedBidiMap

public SortedBidiMap inverseSortedBidiMap()

Description copied from interface: SortedBidiMap

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 SortedMap.

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.

The inverse map returned by inverseBidiMap() should be the same object as returned by this method.

Specified by:

inverseSortedBidiMap in interface SortedBidiMap

Returns:

an inverted bidirectional map

inverseOrderedBidiMap

public OrderedBidiMap inverseOrderedBidiMap()

Description copied from interface: OrderedBidiMap

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 equally.

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:

inverseOrderedBidiMap in interface OrderedBidiMap

Returns:

an inverted bidirectional map

headMap

public java.util.SortedMap headMap(java.lang.Object toKey)

Specified by:

headMap in interface java.util.SortedMap

tailMap

public java.util.SortedMap tailMap(java.lang.Object fromKey)

Specified by:

tailMap in interface java.util.SortedMap

subMap

public java.util.SortedMap subMap(java.lang.Object fromKey,
                                  java.lang.Object toKey)

Specified by:

subMap in interface java.util.SortedMap