org.jboss.cache.eviction
Class BaseSortedEvictionAlgorithm

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

All Implemented Interfaces:

EvictionAlgorithm

Direct Known Subclasses:

ElementSizeAlgorithm, LFUAlgorithm

public abstract class BaseSortedEvictionAlgorithm
extends BaseEvictionAlgorithm

An abstract SortedEvictionAlgorithm.

This class supports early termination of the eviction queue processing. Because the eviction queue is sorted by first to evict to last to evict, when iterating the eviction queue, the first time a node is encountered that does not require eviction will terminate the loop early. This way we don't incur the full breadth of the O(n) = n operation everytime we need to check for eviction (defined by eviction poll time interval).

Author:

Daniel Huang - dhuang@jboss.org - 10/2005

Field Summary

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

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

Constructor Summary

BaseSortedEvictionAlgorithm()

Method Summary

protected void	processQueues(java.util.concurrent.BlockingQueue<EvictionEvent> queue) Event processing for Evict/Add/Visiting of nodes.
protected void	resortEvictionQueue(boolean evictionQueueModified) This method is called to resort the queue after add or visit events have occurred.

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

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jboss.cache.eviction.EvictionAlgorithm

getConfigurationClass

Constructor Detail

BaseSortedEvictionAlgorithm

public BaseSortedEvictionAlgorithm()

Method Detail

processQueues

protected void processQueues(java.util.concurrent.BlockingQueue<EvictionEvent> queue)
                      throws EvictionException

Description copied from class: BaseEvictionAlgorithm

Event processing for Evict/Add/Visiting of nodes.

- On AddEvents a new element is added into the eviction queue - On RemoveEvents, the removed element is removed from the eviction queue. - On VisitEvents, the visited node has its eviction statistics updated (idleTime, numberOfNodeVisists, etc..)

Overrides:

processQueues in class BaseEvictionAlgorithm

Parameters:

queue - queue to inspect

Throws:

EvictionException - in the event of problems

resortEvictionQueue

protected void resortEvictionQueue(boolean evictionQueueModified)

This method is called to resort the queue after add or visit events have occurred.

If the parameter is true, the queue needs to be resorted. If it is false, the queue does not need resorting.

Parameters:

evictionQueueModified - True if the queue was added to or visisted during event processing.