org.apache.commons.jcs.engine.memory.soft

Class SoftReferenceMemoryCache<K,V>

java.lang.Object

org.apache.commons.jcs.engine.memory.AbstractMemoryCache<K,V>

org.apache.commons.jcs.engine.memory.soft.SoftReferenceMemoryCache<K,V>

All Implemented Interfaces:

IMemoryCache<K,V>

public class SoftReferenceMemoryCache<K,V>
extends AbstractMemoryCache<K,V>

A JCS IMemoryCache that has SoftReference to all its values. This cache does not respect ICompositeCacheAttributes.getMaxObjects() as overflowing is handled by Java GC.

The cache also has strong references to a maximum number of objects given by the maxObjects parameter

Author:

halset

Field Summary

Fields inherited from class org.apache.commons.jcs.engine.memory.AbstractMemoryCache

chunkSize, hitCnt, lock, map, missCnt, putCnt

Constructor Summary

Constructors

Constructor and Description
SoftReferenceMemoryCache()

Method Summary

Modifier and Type	Method and Description
ConcurrentMap<K,MemoryElementDescriptor<K,V>>	createMap() Children must implement this method.
int	freeElements(int numberToFree) This can't be implemented.
ICacheElement<K,V>	get(K key) Get an item from the cache
Set<K>	getKeySet() Get a set of the keys for all elements in the memory cache
int	getSize() Returns the current cache size.
IStats	getStatistics() Returns the historical and statistical data for a region's memory cache.
void	initialize(CompositeCache<K,V> hub) For post reflection creation initialization
boolean	remove(K key) Removes an item from the cache.
void	removeAll() Removes all cached items from the cache.
void	update(ICacheElement<K,V> ce) Puts an item to the cache.

Methods inherited from class org.apache.commons.jcs.engine.memory.AbstractMemoryCache

dispose, dumpMap, getCacheAttributes, getCacheName, getCompositeCache, getMultiple, getQuiet, getStatus, setCacheAttributes, waterfal

Methods inherited from class java.lang.Object

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

Constructor Detail

SoftReferenceMemoryCache

public SoftReferenceMemoryCache()

Method Detail

initialize

public void initialize(CompositeCache<K,V> hub)

For post reflection creation initialization

Specified by:

initialize in interface IMemoryCache<K,V>

Overrides:

initialize in class AbstractMemoryCache<K,V>

Parameters:

hub -

createMap

public ConcurrentMap<K,MemoryElementDescriptor<K,V>> createMap()

Description copied from class: AbstractMemoryCache

Children must implement this method. A FIFO implementation may use a tree map. An LRU might use a hashtable. The map returned should be threadsafe.

Specified by:

createMap in class AbstractMemoryCache<K,V>

Returns:

a threadsafe Map

See Also:

AbstractMemoryCache.createMap()

getKeySet

public Set<K> getKeySet()

Description copied from class: AbstractMemoryCache

Get a set of the keys for all elements in the memory cache

Specified by:

getKeySet in interface IMemoryCache<K,V>

Specified by:

getKeySet in class AbstractMemoryCache<K,V>

Returns:

A set of the key type

See Also:

IMemoryCache.getKeySet()

getSize

public int getSize()

Returns the current cache size.

Specified by:

getSize in interface IMemoryCache<K,V>

Overrides:

getSize in class AbstractMemoryCache<K,V>

Returns:

The size value

getStatistics

public IStats getStatistics()

Description copied from interface: IMemoryCache

Returns the historical and statistical data for a region's memory cache.

Specified by:

getStatistics in interface IMemoryCache<K,V>

Overrides:

getStatistics in class AbstractMemoryCache<K,V>

Returns:

statistics about the cache

remove

public boolean remove(K key)
               throws IOException

Removes an item from the cache. This method handles hierarchical removal. If the key is a String and ends with the CacheConstants.NAME_COMPONENT_DELIMITER, then all items with keys starting with the argument String will be removed.

Specified by:

remove in interface IMemoryCache<K,V>

Specified by:

remove in class AbstractMemoryCache<K,V>

Parameters:

key -

Returns:

true if the removal was successful

Throws:

IOException

removeAll

public void removeAll()
               throws IOException

Removes all cached items from the cache.

Specified by:

removeAll in interface IMemoryCache<K,V>

Overrides:

removeAll in class AbstractMemoryCache<K,V>

Throws:

IOException

update

public void update(ICacheElement<K,V> ce)
            throws IOException

Puts an item to the cache.

Specified by:

update in interface IMemoryCache<K,V>

Specified by:

update in class AbstractMemoryCache<K,V>

Parameters:

ce - Description of the Parameter

Throws:

IOException - Description of the Exception

get

public ICacheElement<K,V> get(K key)
                       throws IOException

Get an item from the cache

Specified by:

get in interface IMemoryCache<K,V>

Specified by:

get in class AbstractMemoryCache<K,V>

Parameters:

key - Description of the Parameter

Returns:

Description of the Return Value

Throws:

IOException - Description of the Exception

freeElements

public int freeElements(int numberToFree)
                 throws IOException

This can't be implemented.

Parameters:

numberToFree -

Returns:

0

Throws:

IOException