docs: private SortedSet<Date> calculateDates() {
  
          if (null == m_allDates) {
              SortedSet<Date> result = new TreeSet<>();
              if (isAnyDatePossible()) {
                  Calendar date = getFirstDate();
                  int previousOccurrences = 0;
                  while (showMoreEntries(date, previousOccurrences)) {
                      result.add(date.getTime());
                      toNextDate(date);
                      previousOccurrences++;
                  }
              }
              m_allDates = result;
          }
          return m_allDates;
      }