Using the Java Business Delegate pattern and the Java Session Facade pattern, the Enterprise JavaBeans® (EJB) service interface in the Pega Platform makes service rules available to external, Java-based applications as if the service rules were methods of a session bean.
When the Pega Platform is deployed as an enterprise application, two EJBs named PRServiceStateless and PRServiceStateful implement the Pega Platform session facade. They are the public interface for remote and local access to Pega Platform EJB and Java services. External Java client applications can communicate with the Pega Platform either directly through the PRService beans or through a delegate proxy EJB, generated by the service package.
The service package for a group of EJB service rules generates one or more proxy EJBs that you deploy. The EJB client application communicates with the Pega Platform through the proxy EJB, which forwards the messages from the client to the Pega Platform and returns to the client the response.
EJB services generally process service requests synchronously. That is, they immediately perform their requested processing and return a configured return value while the calling application waits. However, you can configure EJB services to process service requests asynchronously, which means the service queues the request for asynchronous execution and the calling application calls back later for the results. Additionally, you can configure synchronous EJB services to check for specific error conditions that you expect will be temporary — work item locks, for example — and then queue service requests that fail for those reasons for another attempt at a later time.
Use the Application Explorer to see Service EJB rules in your application. Use the Records Explorer to list all Service EJB rules that are available to you.
Service EJB rules belong to the Integration-Services category. A Service EJB rule is an instance of the Rule-Service-EJB rule type.