code: public static int unitsToSeconds(String interval, String unit) {
         if (interval == null || interval.isEmpty()) return 0;
         else if (unit == null) return (int)(Double.parseDouble(interval));
         else if (unit.equals(INTERVAL_DAYS)) return (int)(Double.parseDouble(interval)*86400);
         else if (unit.equals(INTERVAL_HOURS)) return (int)(Double.parseDouble(interval)*3600);
         else if (unit.equals(INTERVAL_MINUTES)) return (int)(Double.parseDouble(interval)*60);
         else return (int)(Double.parseDouble(interval));
     }
docs: Convert interval of specified unit to seconds
  @param interval
  @param unit
  @return