org.jboss.cache.eviction
Class BaseSortedEvictionAlgorithm

java.lang.Object
  extended by org.jboss.cache.eviction.BaseEvictionAlgorithm
      extended by org.jboss.cache.eviction.BaseSortedEvictionAlgorithm
All Implemented Interfaces:
EvictionAlgorithm
Direct Known Subclasses:
ElementSizeAlgorithm, LFUAlgorithm

public abstract class BaseSortedEvictionAlgorithm
extends BaseEvictionAlgorithm
implements EvictionAlgorithm

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
evictionQueue, recycleQueue, region
 
Constructor Summary
BaseSortedEvictionAlgorithm()
           
 
Method Summary
 void process(Region region)
          Process the given region.
protected  void processQueues(Region region)
          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
emptyRecycleQueue, evict, evictCacheNode, getEvictionQueue, initialize, isNodeInUseAndNotTimedOut, processAddedElement, processAddedNodes, processMarkInUseNodes, processRemovedElement, processRemovedNodes, processUnmarkInUseNodes, processVisitedNodes, prune, resetEvictionQueue, setupEvictionQueue, shouldEvictNode
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface org.jboss.cache.eviction.EvictionAlgorithm
getEvictionQueue, resetEvictionQueue
 

Constructor Detail

BaseSortedEvictionAlgorithm

public BaseSortedEvictionAlgorithm()
Method Detail

process

public void process(Region region)
             throws EvictionException
Description copied from class: BaseEvictionAlgorithm
Process the given region.

Eviction Processing encompasses the following:

- Add/Remove/Visit Nodes - Prune according to Eviction Algorithm - Empty/Retry the recycle queue of previously evicted but locked (during actual cache eviction) nodes.

Specified by:
process in interface EvictionAlgorithm
Overrides:
process in class BaseEvictionAlgorithm
Parameters:
region - Cache region to process for eviction.
Throws:
EvictionException

processQueues

protected void processQueues(Region region)
                      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:
region - Cache region to process for eviction.
Throws:
EvictionException

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.


Copyright 1998-2005 JBoss Inc . All Rights Reserved.