Program guide > (deprecated) Partitioning facility > Partitions
Deprecated feature: The partitioning facility (WPF) feature is deprecated. You can configure partitioning with WebSphere eXtreme Scale.
IIOP routing to a partition
Client requests that are submitted using the Object Request Broker (ORB), through the Internet Inter-ORB Protocol (IIOP), can be routed to a particular partition in a cluster. When the client makes a remote request to the routable session bean, the client stubs determine which partition the request is intended for. The current location of the partition is determined using the workload management (WLM) framework. The request is then sent directly to the cluster member currently hosting the partition. If more than one cluster member is hosting the partition then the requests are dispatched in round-robin fashion over the set of candidates.
The previous diagram shows how the request flow is processed in the partitioning facility (WPF)-enabled WAS application servers. When WebSphere eXtreme Scale is installed, a new router called WPFWLM router or partition router is created. All requests go to the WPFWLM router or the partition router first, whether the requests need partition routing or not. If the partition router decides that the request does not need partition routing, the partition router forwards this request to the normal WLM router. If a partition router decides that this request requires partition routing, the partition router uses a partition routing mechanism to route this request directly to the correct partition.
Application writers can control the routing behavior of their applications by writing an <EJBName>_PartitionKey.java class. This class is used to signal whether a partition router or a normal non-partition WLM router is used to do routing. An <EJBName>_PartitionKey.java class exists for each Enterprise JavaBeans™ (EJB) remote interface that to make partition routable. Inside the <EJBName>_PartitionKey.java class, have a static method for each remote method that to make partition routable. The static method returns a not null string to signal partition routable to a partition router. Without either a static method or static method returning null, the partition router handles this request as non-partition routable, and forwards this request to a normal non-partition WLM router. More detail related to the <EJBName>_PartitionKey.java class is provided in the programming section of this guide.