code: @Nullable
    public static XMLGregorianCalendar getXMLCalendar (@Nullable final LocalDateTime aBase)
    {
      if (aBase == null)
        return null;
      return s_aDTFactory.newXMLGregorianCalendar (aBase.getYear (),
                                                   aBase.getMonth ().getValue (),
                                                   aBase.getDayOfMonth (),
                                                   aBase.getHour (),
                                                   aBase.getMinute (),
                                                   aBase.getSecond (),
                                                   aBase.get (ChronoField.MILLI_OF_SECOND),
                                                   DatatypeConstants.FIELD_UNDEFINED);
    }
docs: Get the passed object as {@link XMLGregorianCalendar} with date and time.
  
  @param aBase
  The source object. May be <code>null</code>.
  @return <code>null</code> if the parameter is <code>null</code>.