About BPMN Callable Processes

In Designer version 8.2 and later, the BPMN 2.0 call activity step was introduced to provide the ability to call an external process. A callable process requires the use of a none start event to start the process.

Unlike a message start event, the none start event does not take a receive document. A callable process also requires a defined input/output signature, or global process specification. When you specify a callable process in the call activity step, the inputs/outputs for the parent call activity step are populated with the input/output signature defined on the Global Process Specification page in the Properties view of the callable child process. For more information, see Defining a Global Process Specification.

If a callable process contains a message start event with a subscription filter, that start event and its filter are evaluated only when the callable process is not behaving as a child process. When called by a call activity, the required none start event is used. Therefore, a process model can serve as both a callable process and as a referenced process if both a none start event and a message start event are present.

Note: When a callable process contains both a none start event and a message start event that is configured to use an EDA event type, the message start step and the none start step of the child process must be on different Integration Servers (that is, the Integration Server Name property must be different for each of the two steps). Otherwise a validation error occurs during the build and upload procedure.

The callable process does not use the start and return document method of invocation. Instead, the call activity step passes the entire process pipeline to the none start event in the child process. The child process automatically returns its resulting pipeline back to the parent. For more information about call activity steps and callable processes, see About Call Activities.

Static invocation. In this implementation, the call activity step starts an instance of a specific callable process model with a set of process properties that are defined at design time. The same process model is always called when the call activity step is executed, and the parent process will always wait for this child process to complete. For more information, see About Statically-Invoked Processes. You can start multiple serial instances of the callable process by configuring the call activity step for looping.

Dynamic invocation. In this implementation, you can start one or more callable processes at run time, and, if desired, multiple instances of each of those processes. Furthermore, you define which callable process models are to be started dynamically at run time, depending on pipeline data. You implement this by creating a document reference list of type pub.prt:CallActivityModel called CallActivityModels in the pipeline. The data in this document reference list is used to invoke the desired callable process(es). For example, for orders originating in different countries, a document could start process A for one country, and process B for another country. See About Dynamically-Invoked Processes.