cmvbt/src/IntervalTimer.i3

INTERFACE IntervalTimer;
A client can use the IntervalTimer interface to recieve periodic wake-up calls. 

IMPORT Time;

TYPE
  T <: Public;
  Public = Private OBJECT METHODS
    init (duration: Time.T): T;
    wakeup() := NIL; (* must be overridden. *)
    shutdown();
  END;
  Private <: ROOT;
The init call initializes a timer with the specified duration. Each client must override the wakeup call to perform the periodic task. When finished, clients must call shutdown in order to stop the interval timer from waking up periodically. 

END IntervalTimer.