cdm/src/main/java/ucar/nc2/time/CalendarPeriod.java
public static CalendarPeriod of(String udunit) {
    int value;
    String units;

    String[] split = StringUtil2.splitString(udunit);
    if (split.length == 1) {
      value = 1;
      units =  split[0];

    } else if (split.length == 2) {
      try {
        value = Integer.parseInt(split[0]);
      } catch (Throwable t) {
        return null;
      }
      units =  split[1];
    } else
      return null;


    CalendarPeriod.Field unit = CalendarPeriod.fromUnitString(units);
    return CalendarPeriod.of(value, unit);
  }
public static CalendarPeriod of(String udunit) {
    int value;
    String units;

    String[] split = StringUtil2.splitString(udunit);
    if (split.length == 1) {
      value = 1;
      units =  split[0];

    } else if (split.length == 2) {
      try {
        value = Integer.parseInt(split[0]);
      } catch (Throwable t) {
        return null;
      }
      units =  split[1];
    } else
      return null;


    CalendarPeriod.Field unit = CalendarPeriod.fromUnitString(units);
    return CalendarPeriod.of(value, unit);
  }
Convert a udunit period string into a CalendarPeriod
@param udunit period string : "[val] unit"
@return CalendarPeriod or null if illegal