code: @Nonnull
    public static DayOfWeek getAsDayOfWeek (final int nCalendarDayOfWeek)
    {
      ValueEnforcer.isBetweenInclusive (nCalendarDayOfWeek, "DayOfWeek", 1, 7);
      // Convert Calendar DoW to enum DoW
      final int nIndex = (nCalendarDayOfWeek + 6) % 7;
      return DayOfWeek.of (nIndex == 0 ? 7 : nIndex);
    }
docs: Convert from Calendar day of week to {@link DayOfWeek} enum.
  
  @param nCalendarDayOfWeek
  Day of week - must be between 1 and 7.
  @return {@link DayOfWeek} and never <code>null</code>.
  @since 8.6.3