code: public synchronized void release(int count) {
          used -= count;
          if (used < 0)
              used = 0; // no negative number of ticket!
          if (logger.isDebugEnabled())
              logger.debug("Released " + count + " tickets! (Now " + this.toString() + ")");
          notifyAll();
      }
docs: Releases the given number of tickets and notifies potentially waiting
  threads, that new tickets are in the pool.
  
  @param count
  number of tickets to be released