org.jboss.cache.eviction
Class LRUAlgorithm

java.lang.Object
  |
  +--org.jboss.cache.eviction.LRUAlgorithm

All Implemented Interfaces:

EvictionAlgorithm

Direct Known Subclasses:

AopLRUAlgorithm, FIFOAlgorithm

public class LRUAlgorithm

extends java.lang.Object

implements EvictionAlgorithm

Least recently Used algorithm to purge old data. Note that this algorithm is not thread-safe.

Author:

Ben Wang 02-2004, Daniel Huang

Field Summary

protected NodeEntry	head_
protected org.apache.commons.logging.Log	log_
protected java.util.Map	nodeMap_
protected EDU.oswego.cs.dl.util.concurrent.BoundedBuffer	recycleQueue_
protected Region	region_
protected NodeEntry	tail_

Constructor Summary

LRUAlgorithm()

Method Summary

protected void	demote(Fqn fqn)
protected void	evict(Fqn fqn)
int	evictionQueueSize()
void	process(Region region) No lock is used here since we assume it is single-threaded access by the timer only.
protected void	prune()
void	resetEvictionQueue(Region region) Reset the whole eviction queue.
protected boolean	shouldEvictNode(NodeEntry entry, Region region, long currentTime)

Methods inherited from class java.lang.Object

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

Field Detail

log_

protected org.apache.commons.logging.Log log_

nodeMap_

protected java.util.Map nodeMap_

head_

protected NodeEntry head_

tail_

protected NodeEntry tail_

region_

protected Region region_

recycleQueue_

protected EDU.oswego.cs.dl.util.concurrent.BoundedBuffer recycleQueue_

Constructor Detail

LRUAlgorithm

public LRUAlgorithm()

Method Detail

process

public void process(Region region)
             throws EvictionException

No lock is used here since we assume it is single-threaded access by the timer only.

Specified by:

process in interface EvictionAlgorithm

Parameters:

region -

EvictionException

resetEvictionQueue

public void resetEvictionQueue(Region region)

Description copied from interface: EvictionAlgorithm

Reset the whole eviction queue. Queue may needs to be reset due to corrupted state, for example.

Specified by:

resetEvictionQueue in interface EvictionAlgorithm

Parameters:

region - Region that this algorithm will operate on.

demote

protected void demote(Fqn fqn)
               throws EvictionException

EvictionException

shouldEvictNode

protected boolean shouldEvictNode(NodeEntry entry,
                                  Region region,
                                  long currentTime)

prune

protected void prune()
              throws EvictionException

Throws:

EvictionException

evict

protected void evict(Fqn fqn)
              throws EvictionException

EvictionException

evictionQueueSize

public int evictionQueueSize()