org.apache.commons.collections.map
Class LazyMap
- Map, Serializable
public class LazyMap
implements Map, Serializable
Decorates another
Map
to create objects in the map on demand.
When the
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();
}
}
Map lazy = Lazy.map(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.
$Revision: 1.7 $ $Date: 2004/05/07 23:30:33 $- Stephen Colebourne
- Paul Jack
static Map | decorate(Map map, Factory factory) - Factory method to create a lazily instantiated map.
|
static Map | decorate(Map map, Transformer factory) - Factory method to create a lazily instantiated map.
|
Object | get(Object key)
|
clear , containsKey , containsValue , entrySet , equals , get , getMap , hashCode , isEmpty , keySet , put , putAll , remove , size , toString , values |
factory
protected final Transformer factory
The factory to use to construct elements
LazyMap
protected LazyMap(Map map,
Factory factory)
Constructor that wraps (not copies).
map
- the map to decorate, must not be nullfactory
- the factory to use, must not be null
LazyMap
protected LazyMap(Map map,
Transformer factory)
Constructor that wraps (not copies).
map
- the map to decorate, must not be nullfactory
- the factory to use, must not be null
decorate
public static Map decorate(Map map,
Factory factory)
Factory method to create a lazily instantiated map.
map
- the map to decorate, must not be nullfactory
- the factory to use, must not be null
decorate
public static Map decorate(Map map,
Transformer factory)
Factory method to create a lazily instantiated map.
map
- the map to decorate, must not be nullfactory
- the factory to use, must not be null
Copyright © 2001-2006 Apache Software Foundation. All Rights Reserved.