org.apache.jcs.engine.memory.lru

Class LRUMemoryCache

java.lang.Object

org.apache.jcs.engine.memory.AbstractMemoryCache

org.apache.jcs.engine.memory.AbstractDoulbeLinkedListMemoryCache

org.apache.jcs.engine.memory.lru.LRUMemoryCache

All Implemented Interfaces:

java.io.Serializable, IMemoryCache, MemoryCache

public class LRUMemoryCache
extends AbstractDoulbeLinkedListMemoryCache

A fast reference management system. The least recently used items move to the end of the list and get spooled to disk if the cache hub is configured to use a disk cache. Most of the cache bottelnecks are in IO. There are no io bottlenecks here, it's all about processing power.

Even though there are only a few adjustments necessary to maintain the double linked list, we might want to find a more efficient memory manager for large cache regions.

The LRUMemoryCache is most efficient when the first element is selected. The smaller the region, the better the chance that this will be the case. < .04 ms per put, p3 866, 1/10 of that per get

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.jcs.engine.memory.AbstractDoulbeLinkedListMemoryCache

AbstractDoulbeLinkedListMemoryCache.IteratorWrapper, AbstractDoulbeLinkedListMemoryCache.MapEntryWrapper

Field Summary

Fields inherited from class org.apache.jcs.engine.memory.AbstractDoulbeLinkedListMemoryCache

hitCnt, list, missCnt

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

attr, cache, cacheName, cattr, chunkSize, map, status

Constructor Summary

Constructors

Constructor and Description
LRUMemoryCache()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	adjustListForGet(MemoryElementDescriptor me) Makes the item the first in the list.
protected MemoryElementDescriptor	adjustListForUpdate(ICacheElement ce) Puts an item to the cache.

Methods inherited from class org.apache.jcs.engine.memory.AbstractDoulbeLinkedListMemoryCache

addFirst, addLast, createMap, dumpCacheEntries, dumpCacheSize, dumpMap, freeElements, get, getIterator, getKeyArray, getStatistics, initialize, remove, removeAll, spoolLastElement, update, verifyCache

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

dispose, getCacheAttributes, getCacheName, getCompositeCache, getGroupKeys, getMultiple, getQuiet, getSize, getStatus, setCacheAttributes, waterfal

Methods inherited from class java.lang.Object

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

Constructor Detail

LRUMemoryCache

public LRUMemoryCache()

Method Detail

adjustListForUpdate

protected MemoryElementDescriptor adjustListForUpdate(ICacheElement ce)
                                               throws java.io.IOException

Puts an item to the cache. Removes any pre-existing entries of the same key from the linked list and adds this one first.

Specified by:

adjustListForUpdate in class AbstractDoulbeLinkedListMemoryCache

Parameters:

ce - The cache element, or entry wrapper

Returns:

MemoryElementDescriptor the new node

Throws:

java.io.IOException

adjustListForGet

protected void adjustListForGet(MemoryElementDescriptor me)

Makes the item the first in the list.

Specified by:

adjustListForGet in class AbstractDoulbeLinkedListMemoryCache

Parameters:

me -