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:
- Serializable, Map, 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.
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: 348007 $ $Date: 2005-11-21 22:52:57 +0000 (Mon, 21 Nov 2005) $
- Author:
- Stephen Colebourne, Paul Jack
- See Also:
- Serialized Form
Nested classes/interfaces inherited from interface java.util.Map |
Map.Entry<K,V> |
Fields inherited from class org.apache.commons.collections.map.LazyMap |
factory |
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 interface java.util.Map |
clear, containsKey, containsValue, equals, get, hashCode, isEmpty, put, putAll, remove, size |
LazySortedMap
protected LazySortedMap(SortedMap map,
Factory factory)
- Constructor that wraps (not copies).
- Parameters:
map
- the map to decorate, must not be nullfactory
- 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 nullfactory
- the factory to use, must not be null
- Throws:
IllegalArgumentException
- if map or factory is null
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 nullfactory
- 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 nullfactory
- 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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