code: public static Interval reverseOrder(Interval i) {
  		return new Interval(i.getLabel(), i.getQuality(), (byte) -i.getDirection());
  	}
docs: Reverse the order of an interval. if i.getOrder() is upward,
  return a downward interval, and vice-versa.
  
  A fifth stay a fifth.
  
  @return a new Interval object.