code: public static String addZeros(int i, int size) {
  	String rtn = Caster.toString(i);
  	if (rtn.length() < size) return repeatString("0", size - rtn.length()) + rtn;
  	return rtn;
      }
docs: adds zeros add the begin of a int example: addZeros(2,3) return "002"
  
  @param i number to add nulls
  @param size
  @return min len of return value;