A BPM process needs to interact and collaborate with other processes and services. We have read a lot about invocation patterns in Chapter 5, Interaction Patterns. However, when we invoke a process/service, those invoked processes/services might end in error and raise an exception. This section will help you to learn about exception handling patterns in scenarios where an invoked process raises an error. This section will also include exception propagation pertaining to each pattern.
As per the process state diagram, an activity state transits from ASSIGNED to INVOKED when that assigned activity invokes a process or a service. The following are the activities used to invoke a process or a service:
Call activity invokes a reusable process.
An activity such as service task is used to invoke synchronous services and processes.
Send and receive tasks and throw and catch message events are used to invoke asynchronous services and processes.