org.jasig.portal.utils.threading
Class MapCachingDoubleCheckedCreator<K,T>

java.lang.Object
  org.jasig.portal.utils.threading.DoubleCheckedCreator<T>
      org.jasig.portal.utils.threading.MapCachingDoubleCheckedCreator<K,T>

public abstract class MapCachingDoubleCheckedCreator<K,T>
extends DoubleCheckedCreator<T>

Implementation of DoubleCheckedCreator that stores what it creates in a backing Map. Subclasses need to implement getKey(Object...) to provide a Map key to use for the arguments and create(Object...) to create new instances of the objects.
The default constructor uses a ReferenceMap with hard references to the keys

Version:

$Revision$

Author:

Eric Dalquist

Field Summary

Fields inherited from class org.jasig.portal.utils.threading.DoubleCheckedCreator

logger, readLock, writeLock

Constructor Summary

MapCachingDoubleCheckedCreator()

MapCachingDoubleCheckedCreator(Map<K,T> cache)

MapCachingDoubleCheckedCreator(Map<K,T> cache, ReadWriteLock readWriteLock)

Method Summary

void	clear() Allows the object cache map to be cleared of entries
protected T	create(Object... args)
protected abstract T	createInternal(K key, Object... args)
Map<K,T>	getCacheMap()
protected abstract K	getKey(Object... args)
protected T	retrieve(Object... args)
String	toString()

Methods inherited from class org.jasig.portal.utils.threading.DoubleCheckedCreator

get, invalid

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

MapCachingDoubleCheckedCreator

public MapCachingDoubleCheckedCreator()

MapCachingDoubleCheckedCreator

public MapCachingDoubleCheckedCreator(Map<K,T> cache)

Parameters:

cache - The Map to store created instances in

MapCachingDoubleCheckedCreator

public MapCachingDoubleCheckedCreator(Map<K,T> cache,
                                      ReadWriteLock readWriteLock)

Parameters:

cache - The Map to store created instances in

readWriteLock - the ReadWriteLock to use for the double checked locking

Method Detail

getCacheMap

public final Map<K,T> getCacheMap()

Returns:

A read-only view of the underlying Map used to cache created objects

clear

public final void clear()

Allows the object cache map to be cleared of entries

getKey

protected abstract K getKey(Object... args)

Parameters:

args - Optional arguments passed to DoubleCheckedCreator.get(Object...) used to create a key

Returns:

The key for the specified arguments

createInternal

protected abstract T createInternal(K key,
                                    Object... args)

Parameters:

key - The key to create the object for

args - The object retrieval arguments

Returns:

A new object instance for the key and args

create

protected final T create(Object... args)

Specified by:

create in class DoubleCheckedCreator<T>

Parameters:

args - Arguments to use when creating the object

Returns:

A newly created object

retrieve

protected final T retrieve(Object... args)

Specified by:

retrieve in class DoubleCheckedCreator<T>

Parameters:

args - Arguments to use when retrieving the object

Returns:

An existing object if available

toString

public String toString()

Overrides:

toString in class Object

See Also:

Object.toString()