Program guide > (deprecated) Partitioning facility
Deprecated feature: The partitioning facility (WPF) feature is deprecated. You can configure partitioning with WebSphere eXtreme Scale.
A partitioned stateless session bean
A partitioned stateless session bean (PSSB) is a stateless session bean that implements the PartitionHandlerLocal interface, and utilizes the PartitionManager to create partitions from the partitioning facility's (WPF) framework. The runtime characteristics are the same as a normal stateless session bean from a runtime perspective.
The special features of this bean type include the following:
- While the application starts in the enterprise beans container, the bean is analyzed, and if this bean is a PSSB the PartitionHandlerLocal interface methods are called. The interface implementation methods can use the PartitionManager API to submit requests to the HA manager coordinator to create and activate partitions based upon the current policy.
- During the activation of methods from the client to the server implementation of the PSSB, each client method invocation is intercepted and processed to determine which partition this method should be driven against on the server infrastructure. For example, assume a PSSB named TestBean is being demonstrated, and this bean has a remote interface method called ping(String partition). When the client executes the TestBean.ping(partition) method, the TestBean_PartitionKey.ping(partition) (a class the programmer will create) will process all the method attributes and return a single string to advise the WLM subsystem which partition endpoint the method should be directed towards.
- The PSSB has several methods to handle the state changes that the partition instances might encounter during normal activities. For example, there is a PartitionLoadEvent(String) and PartitionUnLoadEvent(String) method that will be executed if the administrator uses a JMX or wpfadmin command to move a partition endpoint from server to another server. In this case, if a Partition P001 is associated with application server appsvr1, and users execute a wpfadmin move operation that changes the P001 partition from appsvr1 to appsvrN in the cluster, these bean callback methods are invoked. The PSSB on appsvr1 would receive a deactivate callback from the HA manager, and in turn the partitioning facility's runtime would call the PartitionUnLoadEvent(String) method. After this method successfully completes, the HA manager on appsvrN drives an activation related callback method, and the partitioning facility's runtime runs a PartitionLoadEvent(String) on the PSSB.
In summary, a PSSB is a typical session bean that implements and calls methods from the partitioning facility's framework. These methods are similar in many ways to existing EJB callback method handling but have functions that are related to partitioning rather than normal EJB callback methods.
Parent topic:(deprecated) Partitioning facility