public interface

OrderedMap

implements IterableMap
org.apache.commons.collections.OrderedMap
Known Indirect Subclasses

Class Overview

Defines a map that maintains order and allows both forward and backward iteration through that order.

Summary

Public Methods
abstract Object firstKey()
Gets the first key currently in this map.
abstract Object lastKey()
Gets the last key currently in this map.
abstract Object nextKey(Object key)
Gets the next key after the one specified.
abstract OrderedMapIterator orderedMapIterator()
Obtains an OrderedMapIterator over the map.
abstract Object previousKey(Object key)
Gets the previous key before the one specified.
[Expand]
Inherited Methods
From interface java.util.Map
From interface org.apache.commons.collections.IterableMap

Public Methods

public abstract Object firstKey ()

Gets the first key currently in this map.

Returns
  • the first key currently in this map
Throws
NoSuchElementException if this map is empty

public abstract Object lastKey ()

Gets the last key currently in this map.

Returns
  • the last key currently in this map
Throws
NoSuchElementException if this map is empty

public abstract Object nextKey (Object key)

Gets the next key after the one specified.

Parameters
key the key to search for next from
Returns
  • the next key, null if no match or at end

public abstract OrderedMapIterator orderedMapIterator ()

Obtains an OrderedMapIterator over the map.

A ordered map iterator is an efficient way of iterating over maps in both directions.

 BidiMap map = new TreeBidiMap();
 MapIterator it = map.mapIterator();
 while (it.hasNext()) {
   Object key = it.next();
   Object value = it.getValue();
   it.setValue("newValue");
   Object previousKey = it.previous();
 }
 

Returns
  • a map iterator

public abstract Object previousKey (Object key)

Gets the previous key before the one specified.

Parameters
key the key to search for previous from
Returns
  • the previous key, null if no match or at start