Example: Elevator - Explanation

1.

push() Button sends getElevator(toAppropriateFloor) message to the elevatorControl

1.1

elevatorControl repeatedly checks all Queues (of jobs) to find shortest job queue

1.2

creates a new job for the getElevator message

1.3

Invokes next job in the Queue to be done

2.

Elevator works concurrently to do the next Job in the Queue