org.jboss.cache.eviction
Class LRUAlgorithm

java.lang.Object
  org.jboss.cache.eviction.BaseEvictionAlgorithm
      org.jboss.cache.eviction.LRUAlgorithm

All Implemented Interfaces:

EvictionAlgorithm

public class LRUAlgorithm
extends BaseEvictionAlgorithm

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

Author:

Ben Wang 02-2004, Daniel Huang - dhuang@jboss.org

Field Summary

Fields inherited from class org.jboss.cache.eviction.BaseEvictionAlgorithm

allowTombstones, cache, configuration, evictionActionPolicy, evictionAlgorithmConfig, evictionQueue, recycleQueue, regionFqn

Constructor Summary

LRUAlgorithm()

Method Summary

protected void	evict(NodeEntry ne)
java.lang.Class<? extends EvictionAlgorithmConfig>	getConfigurationClass() This is a helper so that the XML parser will be able to select and use the correct EvictionAlgorithmConfig implementation class corresponding to this EvictionAlgorithm.
protected void	prune()
protected EvictionQueue	setupEvictionQueue() This method will create an EvictionQueue implementation and prepare it for use.
protected boolean	shouldEvictNode(NodeEntry entry) This method will check whether the given node should be evicted or not.

Methods inherited from class org.jboss.cache.eviction.BaseEvictionAlgorithm

assignToRegion, canIgnoreEvent, emptyRecycleQueue, evictCacheNode, getEvictionActionPolicy, getEvictionAlgorithmConfig, getEvictionQueue, getNextInQueue, initialize, isNodeInUseAndNotTimedOut, isYoungerThanMinimumTimeToLive, process, processAddedElement, processAddedNodes, processAddedNodes, processMarkInUseNodes, processQueues, processRemovedElement, processRemovedNodes, processUnmarkInUseNodes, processVisitedNodes, resetEvictionQueue, setEvictionActionPolicy, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

LRUAlgorithm

public LRUAlgorithm()

Method Detail

setupEvictionQueue

protected EvictionQueue setupEvictionQueue()
                                    throws EvictionException

Description copied from class: BaseEvictionAlgorithm

This method will create an EvictionQueue implementation and prepare it for use.

Specified by:

setupEvictionQueue in class BaseEvictionAlgorithm

Returns:

The created EvictionQueue to be used as the eviction queue for this algorithm.

Throws:

EvictionException - if there are problems

See Also:

EvictionQueue

shouldEvictNode

protected boolean shouldEvictNode(NodeEntry entry)

Description copied from class: BaseEvictionAlgorithm

This method will check whether the given node should be evicted or not.

Specified by:

shouldEvictNode in class BaseEvictionAlgorithm

Parameters:

entry - NodeEntry to test eviction for.

Returns:

True if the given node should be evicted. False if the given node should not be evicted.

evict

protected void evict(NodeEntry ne)

Overrides:

evict in class BaseEvictionAlgorithm

prune

protected void prune()
              throws EvictionException

Overrides:

prune in class BaseEvictionAlgorithm

Throws:

EvictionException

getConfigurationClass

public java.lang.Class<? extends EvictionAlgorithmConfig> getConfigurationClass()

Description copied from interface: EvictionAlgorithm

This is a helper so that the XML parser will be able to select and use the correct EvictionAlgorithmConfig implementation class corresponding to this EvictionAlgorithm. E.g., the FIFOAlgorithm would return FIFOAlgorithmConfig.class.

Returns:

a class that is used to configure this EvictionAlgorithm.