Hi HuiSheng :
Thanks a lot for your help. But maybe my question is misleading you. The "incoming node" in the question is the previous node from which the token left. Say, both Node-A and Node-B has a outgoing transition connecting to Node-C, when in Node-C's override function, how to know it is coming from Node-A or Node-B by the Node-C's "execution" object?
Thanks a lot.