Package 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:
Serializable, Map, SortedMap, BidiMap, IterableMap, OrderedBidiMap, OrderedMap, SortedBidiMap
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 646777 2008-04-10 12:33:15Z niallp $
Author:
Matthew Hawthorne, Stephen Colebourne
See Also:

  • Field Details

    • comparator

      protected final Comparator comparator
      The comparator to use

  • Constructor Details

    • 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 Details

    • 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
      Specified by:
      firstKey in interface SortedMap
      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
      Specified by:
      lastKey in interface SortedMap
      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