The requirement we got from our support customer, examples attached:
we would like to transfer the process variables of the parent process to the called sub process via the callActivity element.
The subprocess will start through the callActivity and evaluates the variables at the gateways.
Some variables will be changed in the sub process, so there is the need to transfer the variables of the sub process back to the parent process.
So the flow of the parent process can continue in dependence to the transferred variables of the sub process.
The parameter passing (forth and back) should be configured in the call activity (http://www.activiti.org/userguide/index.html#bpmnCallActivity) of the main process via extensions, somehow like
<callActivity id="callCheckCreditProcess" name="Check credit" calledElement="checkCreditProcess">
<!-- what to add here? -->
The question will be if we can extend the extension schema or not. I ask Tom for the rules on that.
As soon as we have that, we "just" have to add the logic to
CallActivityBehaviour (copy variables)
BpmnParse.parseCallActivity (parse configuration)