org.apache.commons.collections.map
Class LazySortedMap

java.lang.Object
  extended byorg.apache.commons.collections.map.AbstractMapDecorator
      extended byorg.apache.commons.collections.map.LazyMap
          extended byorg.apache.commons.collections.map.LazySortedMap
All Implemented Interfaces:
Map, Serializable, SortedMap

public class LazySortedMap
extends LazyMap
implements SortedMap

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: 1.6 $ $Date: 2004/04/09 10:36:01 $
Author:
Stephen Colebourne, Paul Jack
See Also:
Serialized Form

Nested Class Summary
 
Nested classes inherited from class java.util.Map
Map.Entry
 
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 map, Factory factory)
          Constructor that wraps (not copies).
protected LazySortedMap(SortedMap map, Transformer factory)
          Constructor that wraps (not copies).
 
Method Summary
 Comparator comparator()
           
static SortedMap decorate(SortedMap map, Factory factory)
          Factory method to create a lazily instantiated sorted map.
static SortedMap decorate(SortedMap map, Transformer factory)
          Factory method to create a lazily instantiated sorted map.
 Object firstKey()
           
protected  SortedMap getSortedMap()
          Gets the map being decorated.
 SortedMap headMap(Object toKey)
           
 Object lastKey()
           
 SortedMap subMap(Object fromKey, Object toKey)
           
 SortedMap tailMap(Object fromKey)
           
 
Methods inherited from class org.apache.commons.collections.map.LazyMap
decorate, 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 map,
                        Factory 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

LazySortedMap

protected LazySortedMap(SortedMap map,
                        Transformer 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 SortedMap decorate(SortedMap map,
                                 Factory 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

decorate

public static SortedMap decorate(SortedMap map,
                                 Transformer 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 getSortedMap()
Gets the map being decorated.

Returns:
the decorated map

firstKey

public Object firstKey()
Specified by:
firstKey in interface SortedMap

lastKey

public Object lastKey()
Specified by:
lastKey in interface SortedMap

comparator

public Comparator comparator()
Specified by:
comparator in interface SortedMap

subMap

public SortedMap subMap(Object fromKey,
                        Object toKey)
Specified by:
subMap in interface SortedMap

headMap

public SortedMap headMap(Object toKey)
Specified by:
headMap in interface SortedMap

tailMap

public SortedMap tailMap(Object fromKey)
Specified by:
tailMap in interface SortedMap


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