code: private static int toInterval(String interval) throws ScheduleException {
  	interval = interval.trim().toLowerCase();
  	int i = Caster.toIntValue(interval, 0);
  	if (i == 0) {
  	    interval = interval.trim();
  	    if (interval.equals("once")) return INTERVAL_ONCE;
  	    else if (interval.equals("daily")) return INTERVAL_DAY;
  	    else if (interval.equals("day")) return INTERVAL_DAY;
  	    else if (interval.equals("monthly")) return INTERVAL_MONTH;
  	    else if (interval.equals("month")) return INTERVAL_MONTH;
  	    else if (interval.equals("weekly")) return INTERVAL_WEEK;
  	    else if (interval.equals("week")) return INTERVAL_WEEK;
  	    throw new ScheduleException("invalid interval definition [" + interval + "], valid values are [once,daily,monthly,weekly or number]");
  	}
  	if (i < 10) {
  	    throw new ScheduleException("interval must be at least 10");
  	}
  	return i;
      }
docs: translate a String interval definition to a int definition
  
  @param interval
  @return interval
  @throws ScheduleException