IBM WebSphere Extended Deployment (XD)TM
Release 6.0

com.ibm.websphere.objectgrid.plugins
Evictor



Data contained in a BackingMap are evicted when the map is full. This Evictor plugin is used by the BaseMap to determine when and what to evict from the map based on some algorithm (LRU, LFU, time based, etc).


See Also:
    setEvictor(Evictor)



Method Summary
public  voidinitialize(com.ibm.websphere.objectgrid.BackingMap, com.ibm.websphere.objectgrid.plugins.EvictionEventCallback)
          

This method is used by a Map instance during the evictor intialization time. .

public  voiddestroy()
          

This is called when the Map associate with this evictor is destroyed. It's the.

public  voidapply(com.ibm.websphere.objectgrid.plugins.LogSequence)
           This is called after a transaction has committed to allow the evictor to track object usage in a backing map.

Method Detail

initialize

public void initialize(BackingMap map,EvictionEventCallback callback)

This method is used by a Map instance during the evictor intialization time. The calls this method so the Evictor instance can have references to the BackingMap instance and the EvictionEventCallback instance. The evictor can then signal events to have specific entries evicted using the callback.

Parameters:
    map - the BackingMap instance
    callback - the EvictionEventCallback instance


destroy

public void destroy()

This is called when the Map associate with this evictor is destroyed. It's the opposite of initialize. When this method is called, the Evictor can free up any resource it uses.



apply

public void apply(LogSequence sequence)
This is called after a transaction has committed to allow the evictor to track object usage in a backing map. This will also report any entries that have been successfully evicted. Note, this method is not called for transactions that are rolled back. If there is a need to track object usage for rolled back transactions, then the Evictor must implement the com.ibm.websphere.objectgrid.plugins.RollbackEvictor interface as well.
Parameters:
    sequence - LogSequence of changes to the map


IBM WebSphere Extended Deployment (XD)TM
Release 6.0