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:

BidiMap, IterableMap, Map, OrderedBidiMap, OrderedMap, Serializable, SortedBidiMap, SortedMap

public class DualTreeBidiMap

extends AbstractDualBidiMap

implements SortedBidiMap, 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

Version:

$Id: DualTreeBidiMap.java,v 1.14 2004/06/11 23:27:37 scolebourne Exp $

Author:

Matthew Hawthorne, Stephen Colebourne

See Also:

Serialized Form

Nested Class Summary

protected static class	DualTreeBidiMap.BidiOrderedMapIterator Inner class MapIterator.
protected static class	DualTreeBidiMap.ViewMap Internal sorted map view.

Nested classes inherited from class org.apache.commons.collections.bidimap.AbstractDualBidiMap

AbstractDualBidiMap.BidiMapIterator, AbstractDualBidiMap.EntrySet, AbstractDualBidiMap.EntrySetIterator, AbstractDualBidiMap.KeySet, AbstractDualBidiMap.KeySetIterator, AbstractDualBidiMap.MapEntry, AbstractDualBidiMap.Values, AbstractDualBidiMap.ValuesIterator, AbstractDualBidiMap.View

Field Summary

protected Comparator

comparator The comparator to use

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

entrySet, inverseBidiMap, keySet, maps, values

Constructor Summary

	DualTreeBidiMap() Creates an empty DualTreeBidiMap
	DualTreeBidiMap(Comparator comparator) Constructs a DualTreeBidiMap using the specified Comparator.
	DualTreeBidiMap(Map map) Constructs a DualTreeBidiMap and copies the mappings from specified Map.
protected	DualTreeBidiMap(Map normalMap, Map reverseMap, BidiMap inverseBidiMap) Constructs a DualTreeBidiMap that decorates the specified maps.

Method Summary

Comparator	comparator()
protected BidiMap	createBidiMap(Map normalMap, Map reverseMap, BidiMap inverseMap) Creates a new instance of this object.
Object	firstKey() Gets the first key currently in this map.
SortedMap	headMap(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.
Object	lastKey() Gets the last key currently in this map.
Object	nextKey(Object key) Gets the next key after the one specified.
OrderedMapIterator	orderedMapIterator() Obtains an ordered map iterator.
Object	previousKey(Object key) Gets the previous key before the one specified.
SortedMap	subMap(Object fromKey, Object toKey)
SortedMap	tailMap(Object fromKey)

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

clear, containsKey, containsValue, createEntrySetIterator, createKeySetIterator, createMap, 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 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, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, putAll, remove, size, values

Field Detail

comparator

protected final Comparator comparator

The comparator to use

Constructor Detail

DualTreeBidiMap

public DualTreeBidiMap()

Creates an empty DualTreeBidiMap

DualTreeBidiMap

public DualTreeBidiMap(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(Comparator comparator)

Constructs a DualTreeBidiMap using the specified Comparator.

Parameters:

comparator - the Comparator

DualTreeBidiMap

protected DualTreeBidiMap(Map normalMap,
                          Map reverseMap,
                          BidiMap 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 Detail

createBidiMap

protected BidiMap createBidiMap(Map normalMap,
                                Map reverseMap,
                                BidiMap inverseMap)

Creates a new instance of this object.

Specified by:

createBidiMap in class AbstractDualBidiMap

Parameters:

normalMap - the normal direction map

reverseMap - the reverse direction map

inverseMap - the inverse BidiMap

Returns:

new bidi map

comparator

public Comparator comparator()

Specified by:

comparator in interface SortedMap

firstKey

public Object firstKey()

Description copied from interface: OrderedMap

Gets the first key currently in this map.

Specified by:

firstKey in interface OrderedMap

Returns:

the first key currently in this map

lastKey

public Object lastKey()

Description copied from interface: OrderedMap

Gets the last key currently in this map.

Specified by:

lastKey in interface OrderedMap

Returns:

the last key currently in this map

nextKey

public Object nextKey(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 Object previousKey(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 SortedMap headMap(Object toKey)

Specified by:

headMap in interface SortedMap

tailMap

public SortedMap tailMap(Object fromKey)

Specified by:

tailMap in interface SortedMap

subMap

public SortedMap subMap(Object fromKey,
                        Object toKey)

Specified by:

subMap in interface SortedMap