public enum Day
{
   Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday;
   public String toString()
   {
      return super.toString().substring(0, 3);
   }
   private static Day[] iDayValues = Day.values();
   public static Day getFirst()
   {
      return iDayValues[0];
   }
   public boolean isLast()
   {
      return this==iDayValues[iDayValues.length - 1];
   }
   public Day getNext()
   {
      int tNewPos = ordinal() + 1;
      if (tNewPos==iDayValues.length)
         return iDayValues[0];
      else
         return iDayValues[tNewPos];
   }
}