When the random walker walks from one state to another, it computes all possible rendez-vous between all active objects in the application. When it reaches the next state it display the information about the current state, the possible rendez-vous and the transitions. For instance, in the next graphic, the random walker shows the current state, all possible rendez-vous and transitions. There is a rendez-vous between the two active objects. There is a transition too when an active object is waiting for a timeout.
Every transition is identified by a number.
This button tells the random walker to select the next transition. The last button is ised to terminate the execution of the random walker. When there's no-one transition to select the application has reached a deadlock state. You can invoke two methods of class RandomWalker from your program under test. This method is used to named the next select statement, the first argument anActiveObj must be an active object.