/* the main method instantiates drinkers and directs them to
   a newly-instantiated wall of beer.
*/
public class Sing99Bob {
  public static void main(String[] args) {
    ((NeedToFindBeer)(new Drinkers())).pointAtBeer(new WallOfBeer());
  }
}

  interface NeedToFindBeer { void pointAtBeer(WallOfBeer wob); }

  /* an instance of Drinkers, after being pointed at a wall containing
     beer, will periodically take one down.  The singing is driven by
     the taking of the beer.
  */
  class Drinkers extends Thread implements NeedToFindBeer {
    static final int drinkRate = 2;
    WallOfBeer ourBeer;
    public void run() {
      while (ourBeer.takeOne()>0) {
       try { Thread.sleep(drinkRate*1000); } catch (InterruptedException ignore) {}
      }
    }
    public void pointAtBeer(WallOfBeer wob) {
      ourBeer = wob;
      this.start();
    }
  }

  interface Countable { int howMany(); }

  /* an instance of a WallOfBeer will maintain a count of the
     beer bottles.  The wall has an associated Narrator who
     reports each time the number of bottles is changed.
  */
  class WallOfBeer implements Countable {
    static final int full = 99;
    int count = 0;
    WallWatcher ww;
    {
      ww = new Narrator();
      putSome(full);
    }
    void putSome(int some) {
      cou