org.shiftone.cache.decorator.soft
Class SoftCache

java.lang.Object
  org.shiftone.cache.decorator.soft.SoftCache

All Implemented Interfaces:

Cache, ReapableCache

public class SoftCache

extends java.lang.Object

implements Cache, ReapableCache

Memory sensitive cache.

This cache implementation proxies to a cache that was passed to it's constructor. When objects are added to the cache, the object wrapped in a SoftReference, and then the Reference is added to the delegate cache.

Once a SoftCache is created for a cache, the SoftCache should always be used to access this cache. Using the original cache directly is not recommended.

Note that there are no guarantees as to how long objects you put in cache will remain there. This is entirely at the digression of the garbage collector, which tends to be hasty about freeing up memory.

Version:

$Revision: 1.8 $

Author:

Jeff Drost

Nested Class Summary

(package private) class

SoftCache.KeyReference Class KeyReference

Constructor Summary

SoftCache(Cache cache)

Method Summary

void	addObject(java.lang.Object key, java.lang.Object cacheObject) adds an object to the cache
void	clear() Removes ALL keys and values from the cache.
java.lang.Object	getObject(java.lang.Object key) Gets a soft reference out of the underlying cache implementation, and then returns the value held by the reference.
void	remove(java.lang.Object key) remove a specific key/value pair from the cache
void	removeExpiredElements() Cleans all cache elements out that have had their objects collected by the GC.
int	size() The number of key/value pares in the cache
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

SoftCache

public SoftCache(Cache cache)

Method Detail

addObject

public void addObject(java.lang.Object key,
                      java.lang.Object cacheObject)

Description copied from interface: Cache

adds an object to the cache

Specified by:

addObject in interface Cache

getObject

public java.lang.Object getObject(java.lang.Object key)

Gets a soft reference out of the underlying cache implementation, and then returns the value held by the reference.

Specified by:

getObject in interface Cache

remove

public final void remove(java.lang.Object key)

Description copied from interface: Cache

remove a specific key/value pair from the cache

Specified by:

remove in interface Cache

size

public final int size()

Description copied from interface: Cache

The number of key/value pares in the cache

Specified by:

size in interface Cache

clear

public final void clear()

Description copied from interface: Cache

Removes ALL keys and values from the cache. Use with digression. Using this method too frequently may defeat the purpose of caching.

Specified by:

clear in interface Cache

removeExpiredElements

public void removeExpiredElements()

Cleans all cache elements out that have had their objects collected by the GC.

Specified by:

removeExpiredElements in interface ReapableCache

toString

public final java.lang.String toString()