public void run() {
   try {
     while (!Thread.interrupted()) {
       // A new customer arrives; assign a WaitPerson:
       WaitPerson wp = waitPersons.get(rand.nextInt(waitPersons.size()));
       Customer c = new Customer(wp);
       exec.execute(c);
       TimeUnit.MILLISECONDS.sleep(100);
     }
   } catch (InterruptedException e) {
     print("Restaurant interrupted");
   }
   print("Restaurant closing");
 }