Java Doc for LazyMap.java in  » Library » Apache-common-Collections » org » apache » commons » collections » map » Java Source Code / Java DocumentationJava Source Code and Java Documentation

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();
 }
 }
 Map lazy = Lazy.map(new HashMap(), factory);
 Object obj = lazy.get("NOW");
 

Note that LazyMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. The simplest approach is to wrap this map using java.util.Collections.synchronizedMap(Map) . This class may throw exceptions when accessed by concurrent threads without synchronization.

This class is Serializable from Commons Collections 3.1.
since:
   Commons Collections 3.0
version:
   $Revision: 348007 $ $Date: 2005-11-21 22:52:57 +0000 (Mon, 21 Nov 2005) $
author:
   Stephen Colebourne
author:
   Paul Jack