code: private static Calendar valueAsCalendar(Object value) {
  		Date date = (Date) value;
  		Calendar cal = Calendar.getInstance();
  		cal.setTime(date);
  		return cal;
  	}
docs: Convert a Date value to a Calendar. Calcite's fromCalendarField functions use the
  Calendar.get methods, so the raw values of the individual fields are preserved when
  converted to the String formats.
  
  @return get the Calendar value