LRUMemoryCache (Commons JCS 2.0.0-SNAPSHOT API)

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org.apache.jcs.engine.memory.lru
Class LRUMemoryCache<K extends Serializable,V extends Serializable>

java.lang.Object
  org.apache.jcs.engine.memory.AbstractMemoryCache<K,V>
      org.apache.jcs.engine.memory.AbstractDoubleLinkedListMemoryCache<K,V>
          org.apache.jcs.engine.memory.lru.LRUMemoryCache<K,V>

All Implemented Interfaces:: Serializable, IRequireScheduler, IMemoryCache<K,V>

public class LRUMemoryCache<K extends Serializable,V extends Serializable>
extends AbstractDoubleLinkedListMemoryCache<K,V>
extends AbstractDoubleLinkedListMemoryCache<K,V>

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 bottlenecks 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.AbstractDoubleLinkedListMemoryCache
`AbstractDoubleLinkedListMemoryCache.IteratorWrapper<K extends Serializable,V extends Serializable>, AbstractDoubleLinkedListMemoryCache.MapEntryWrapper<K extends Serializable,V extends Serializable>`

Field Summary

Fields inherited from class org.apache.jcs.engine.memory.AbstractDoubleLinkedListMemoryCache
`hitCnt, list, missCnt`

Fields inherited from class org.apache.jcs.engine.memory.AbstractMemoryCache
`cache, cacheAttributes, cacheName, chunkSize, elementAttributes, map, status`

Constructor Summary
`LRUMemoryCache()`

Method Summary
`protected void`	`adjustListForGet(MemoryElementDescriptor<K,V> me)` Makes the item the first in the list.
`protected MemoryElementDescriptor<K,V>`	`adjustListForUpdate(ICacheElement<K,V> ce)` Puts an item to the cache.

Methods inherited from class org.apache.jcs.engine.memory.AbstractDoubleLinkedListMemoryCache
`addFirst, addLast, createMap, dumpCacheEntries, dumpCacheSize, freeElements, get, getIterator, getKeySet, getStatistics, initialize, remove, removeAll, spoolLastElement, update, verifyCache`

Methods inherited from class org.apache.jcs.engine.memory.AbstractMemoryCache
`dispose, dumpMap, getCacheAttributes, getCacheName, getCompositeCache, getGroupKeys, getGroupNames, getMultiple, getQuiet, getSize, getStatus, setCacheAttributes, setScheduledExecutorService, 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<K,V> adjustListForUpdate(ICacheElement<K,V> ce)
                                                                                              throws 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 AbstractDoubleLinkedListMemoryCache<K extends Serializable,V extends Serializable>

Parameters:: ce - The cache element, or entry wrapper
Returns:: MemoryElementDescriptor the new node
Throws:: IOException

adjustListForGet

protected void adjustListForGet(MemoryElementDescriptor<K,V> me)

Makes the item the first in the list.

Specified by:: adjustListForGet in class AbstractDoubleLinkedListMemoryCache<K extends Serializable,V extends Serializable>

Parameters:: me -