I’ve heard about this approach with 2 queues as well elsewhere. The thing is, at any given time and for a given class instance, there can be at most 1 self-directed event (non-delayed). Consequently, using a queue for self-directed events is overkill. All that is needed is a simple reference to the last sent self-directed event. When that reference is empty, it’s time to get next event from the queue.
I’m not following you all the way but my understanding of the xtUML formalism is that there 3 kinds of queues; bridge queues, class instance queues and a delay queue (probably what you call the time domain). The delay queue is only a holding place for delayed events waiting for their timer to expire. When that happen, the event is pushed to the class instance queue in the same way as any non-self-directed event. So, refering the original post, the answer is Yes.
Probably a good time to check out if Leslie Lamport has something to say on the subject matter.
/Nils
