org.apache.commons.collections.map
Class LazySortedMap<K,V>

java.lang.Object
  org.apache.commons.collections.map.AbstractMapDecorator<K,V>
      org.apache.commons.collections.map.LazyMap<K,V>
          org.apache.commons.collections.map.LazySortedMap<K,V>

All Implemented Interfaces:

Serializable, Map<K,V>, SortedMap<K,V>

public class LazySortedMap<K,V>
extends LazyMap<K,V>
implements SortedMap<K,V>

Decorates another SortedMap to create objects in the map on demand.

When the LazyMap.get(Object) method is called with a key that does not exist in the map, the factory is used to create the object. The created object will be added to the map using the requested key.

For instance:

 Factory factory = new Factory() {
     public Object create() {
         return new Date();
     }
 }
 SortedMap lazy = Lazy.sortedMap(new HashMap(), factory);
 Object obj = lazy.get("NOW");
 

After the above code is executed, obj will contain a new Date instance. Furthermore, that Date instance is mapped to the "NOW" key in the map.

This class is Serializable from Commons Collections 3.1.

Since:

Commons Collections 3.0

Version:

$Revision: 1.1.1.1 $ $Date: 2005/05/23 04:35:53 $

Author:

Stephen Colebourne, Matt Hall, John Watkinson, Paul Jack

See Also:

Serialized Form

Nested Class Summary

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

Map.Entry<K,V>

Field Summary

Fields inherited from class org.apache.commons.collections.map.LazyMap

factory

Fields inherited from class org.apache.commons.collections.map.AbstractMapDecorator

map

Constructor Summary

protected

LazySortedMap(SortedMap<K,V> map, Factory<V> factory) Constructor that wraps (not copies).

Method Summary

Comparator<? super K>	comparator()
static <K,V> SortedMap<K,V>	decorate(SortedMap<K,V> map, Factory<V> factory) Factory method to create a lazily instantiated sorted map.
K	firstKey()
protected SortedMap<K,V>	getSortedMap() Gets the map being decorated.
SortedMap<K,V>	headMap(K toKey)
K	lastKey()
SortedMap<K,V>	subMap(K fromKey, K toKey)
SortedMap<K,V>	tailMap(K fromKey)

Methods inherited from class org.apache.commons.collections.map.LazyMap

decorate, get

Methods inherited from class org.apache.commons.collections.map.AbstractMapDecorator

clear, containsKey, containsValue, entrySet, equals, getMap, hashCode, isEmpty, keySet, put, putAll, remove, size, toString, values

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, put, putAll, remove, size, values

Constructor Detail

LazySortedMap

protected LazySortedMap(SortedMap<K,V> map,
                        Factory<V> factory)

Constructor that wraps (not copies).

Parameters:

map - the map to decorate, must not be null

factory - the factory to use, must not be null

Throws:

IllegalArgumentException - if map or factory is null

Method Detail

decorate

public static <K,V> SortedMap<K,V> decorate(SortedMap<K,V> map,
                                            Factory<V> factory)

Factory method to create a lazily instantiated sorted map.

Parameters:

map - the map to decorate, must not be null

factory - the factory to use, must not be null

Throws:

IllegalArgumentException - if map or factory is null

getSortedMap

protected SortedMap<K,V> getSortedMap()

Gets the map being decorated.

Returns:

the decorated map

firstKey

public K firstKey()

Specified by:

firstKey in interface SortedMap<K,V>

lastKey

public K lastKey()

Specified by:

lastKey in interface SortedMap<K,V>

comparator

public Comparator<? super K> comparator()

Specified by:

comparator in interface SortedMap<K,V>

subMap

public SortedMap<K,V> subMap(K fromKey,
                             K toKey)

Specified by:

subMap in interface SortedMap<K,V>

headMap

public SortedMap<K,V> headMap(K toKey)

Specified by:

headMap in interface SortedMap<K,V>

tailMap

public SortedMap<K,V> tailMap(K fromKey)

Specified by:

tailMap in interface SortedMap<K,V>