WebSphere eXtreme Scale Best Practices for Operation and Management

94 WebSphere eXtreme Scale Best Practices for Operation and Management

Example 5-14 Plug in an ObjectGridEventListener

<?xml version="1.0" encoding="UTF-8"?>

<objectGridConfig xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://ibm.com/ws/objectgrid/config ../objectGrid.xsd"

xmlns="http://ibm.com/ws/objectgrid/config">

<objectGrids>

<objectGrid name="grid1">

<bean id="ObjectGridEventListener"

className="com.company.org.CustomObjectGridEventListener" />

<backingMap name="map1" ttlEvictorType="NONE" />

</objectgrid>

</objectGrids>

Depending on which events the custom listener must handle, it can implement one or more of

the interfaces that are listed in Table 5-1.

Table 5-1 List of interfaces and their methods

5.4 BackingMap plug-ins

A BackingMap plug-in is a plug-in that affects the behavior of a map. The following plug-ins

are available for a BackingMap:

򐂰 Evictor: An evictor plug-in is a mechanism that is provided for evicting cache entries.

There are default evictors and an interface for creating custom evictors.

򐂰 ObjectTransformer: An ObjectTransformer plug-in allows you to serialize, deserialize, and

copy objects in the cache, either alone or in conjunction with the object’s own Serializable

or Externalizable methods.

򐂰 OptimisticCallback: An OptimisticCallback plug-in allows you to customize versioning and

comparison operations of cache objects when you are using the optimistic lock strategy.

Class name Method to implement Description

com.ibm.websphere.objectgrid.pl

ugins.ObjectGridEventGroup.Sh

ardLifecycle

򐂰 initialize()

򐂰 destroy()

򐂰 ObjectGrid shard

initialization.

򐂰 ObjectGrid shard destroy.

com.ibm.websphere.objectgrid.pl

ugins.ObjectGridEventGroup.Sh

ardEvents

򐂰 shardActivated()

򐂰 shardDeactivated()

򐂰 Called when the shard

becomes a primary.

򐂰 Called when the shard

becomes a replica.

com.ibm.websphere.objectgrid.pl

ugins.ObjectGridEventGroup.Tra

nsactionEvents

򐂰 transactionBegin()

򐂰 transactionEnd()

򐂰 Called at the beginning of a

session transaction.

򐂰 Called at the end of a

transaction.

Note: Implementing the com.ibm.websphere.objectgrid.plugins.ObjectGridEventListener is

the same as implementing the following interfaces:

򐂰 com.ibm.websphere.objectgrid.plugins.ObjectGridEventGroup.TransactionEvents

򐂰 com.ibm.websphere.objectgrid.plugins.ObjectGridEventGroup.ShardLifecycle