org.apache.commons.collections.map
Class LazySortedMap

java.lang.Object
  org.apache.commons.collections.map.AbstractMapDecorator
      org.apache.commons.collections.map.LazyMap
          org.apache.commons.collections.map.LazySortedMap

All Implemented Interfaces:

java.io.Serializable, java.util.Map, java.util.SortedMap

public class LazySortedMap
extends LazyMap
implements java.util.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.

Note that LazySortedMap 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 Collections.synchronizedSortedMap(java.util.SortedMap). 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: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $

Author:

Stephen Colebourne, Paul Jack

See Also:

Serialized Form

Nested Class Summary

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

java.util.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(java.util.SortedMap map, Factory factory) Constructor that wraps (not copies).
protected	LazySortedMap(java.util.SortedMap map, Transformer factory) Constructor that wraps (not copies).

Method Summary

java.util.Comparator	comparator()
static java.util.SortedMap	decorate(java.util.SortedMap map, Factory factory) Factory method to create a lazily instantiated sorted map.
static java.util.SortedMap	decorate(java.util.SortedMap map, Transformer factory) Factory method to create a lazily instantiated sorted map.
java.lang.Object	firstKey()
protected java.util.SortedMap	getSortedMap() Gets the map being decorated.
java.util.SortedMap	headMap(java.lang.Object toKey)
java.lang.Object	lastKey()
java.util.SortedMap	subMap(java.lang.Object fromKey, java.lang.Object toKey)
java.util.SortedMap	tailMap(java.lang.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(java.util.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:

java.lang.IllegalArgumentException - if map or factory is null

LazySortedMap

protected LazySortedMap(java.util.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:

java.lang.IllegalArgumentException - if map or factory is null

Method Detail

decorate

public static java.util.SortedMap decorate(java.util.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:

java.lang.IllegalArgumentException - if map or factory is null

decorate

public static java.util.SortedMap decorate(java.util.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:

java.lang.IllegalArgumentException - if map or factory is null

getSortedMap

protected java.util.SortedMap getSortedMap()

Gets the map being decorated.

Returns:

the decorated map

firstKey

public java.lang.Object firstKey()

Specified by:

firstKey in interface java.util.SortedMap

lastKey

public java.lang.Object lastKey()

Specified by:

lastKey in interface java.util.SortedMap

comparator

public java.util.Comparator comparator()

Specified by:

comparator in interface java.util.SortedMap

subMap

public java.util.SortedMap subMap(java.lang.Object fromKey,
                                  java.lang.Object toKey)

Specified by:

subMap in interface java.util.SortedMap

headMap

public java.util.SortedMap headMap(java.lang.Object toKey)

Specified by:

headMap in interface java.util.SortedMap

tailMap

public java.util.SortedMap tailMap(java.lang.Object fromKey)

Specified by:

tailMap in interface java.util.SortedMap