I don't suppose there's a way in the current Activiti Designer to have a Gateway in which many executions can come in, but only the first that arrives goes out … the others are discarded / cancelled
I've tried using an ExclusiveGateway but couldn't seem to get it to work .. not sure if I'm doing it correctly though.
Right now I'm attempting a slight kludgy work-around. Say I have two concurrent UserTasks A & B, only one of which needs to complete before it moves onto a third UserTask C. When either A or B completes, execution goes to a ServiceTask that cancels the other parallel UserTask via an API call and then moves onto UserTask C
I dont know about the designer, but engine-wise you should be able to implement that pretty simply. Take a look at the ParallelGatewayActivity, that should give you an idea on how you can implement such a gateway.
