public void run(int pumpCount, int attendantCount, int duration){
    makePumps(pumpCount);   
    makeAttendants(attendantCount);
    for (int i=0;i<duration;i++){
      carQueue();
      
      while(freePump()&&l.hasNext()&&freeAttendant()){
        tryToFill();        
      }
      
      nextFrame();
    }
  }