org.apache.commons.collections
Interface OrderedMap
- All Superinterfaces:
- IterableMap, Map
- All Known Subinterfaces:
- OrderedBidiMap, SortedBidiMap
- All Known Implementing Classes:
- AbstractOrderedMapDecorator, AbstractLinkedMap, ListOrderedMap
- public interface OrderedMap
- extends IterableMap
Defines a map that maintains order and allows both forward and backward
iteration through that order.
- Since:
- Commons Collections 3.0
- Version:
- $Revision: 1.5 $ $Date: 2004/01/14 21:43:03 $
- Author:
- Stephen Colebourne
Methods inherited from interface java.util.Map |
clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, put, putAll, remove, size, values |
orderedMapIterator
public 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
firstKey
public 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
lastKey
public 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
nextKey
public 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
previousKey
public 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
Copyright © 2001-2004 Apache Software Foundation. All Rights Reserved.