private DtStart getStartDateProperty(Date startDate) {

    DateTime date = convertRaplaLocaleToUTC(startDate);
    TimeZoneRegistry registry = TimeZoneRegistryFactory.getInstance().createRegistry();
    net.fortuna.ical4j.model.TimeZone tz = registry.getTimeZone(timeZone.getID());
    date.setTimeZone(tz);
    return new DtStart(date);
  }
  @Inject
  public Export2iCalConverter(
      TimeZoneConverter timezoneConverter,
      RaplaLocale raplaLocale,
      Logger logger,
      ClientFacade facade)
      throws RaplaException {
    this.timezoneConverter = timezoneConverter;
    this.facade = facade;
    this.raplaLocale = raplaLocale;
    this.logger = logger;
    TimeZone zone = timezoneConverter.getImportExportTimeZone();

    calendar = raplaLocale.createCalendar();
    DynamicType[] dynamicTypes =
        facade.getDynamicTypes(DynamicTypeAnnotations.VALUE_CLASSIFICATION_TYPE_RESOURCE);
    for (DynamicType type : dynamicTypes) {
      if (type.getAnnotation(DynamicTypeAnnotations.KEY_LOCATION) != null) {
        hasLocationType = true;
      }
    }
    CompatibilityHints.setHintEnabled(CompatibilityHints.KEY_RELAXED_VALIDATION, true);

    RaplaConfiguration config =
        facade
            .getSystemPreferences()
            .getEntry(Export2iCalPlugin.ICAL_CONFIG, new RaplaConfiguration());
    global_export_attendees =
        config
            .getChild(Export2iCalPlugin.EXPORT_ATTENDEES)
            .getValueAsBoolean(Export2iCalPlugin.DEFAULT_exportAttendees);
    global_export_attendees_participation_status =
        config
            .getChild(Export2iCalPlugin.EXPORT_ATTENDEES_PARTICIPATION_STATUS)
            .getValue(Export2iCalPlugin.DEFAULT_attendee_participation_status);

    try {
      exportAttendeesAttribute =
          config.getChild(Export2iCalPlugin.EXPORT_ATTENDEES_EMAIL_ATTRIBUTE).getValue();
    } catch (ConfigurationException e) {
      exportAttendeesAttribute = "";
      getLogger().info("ExportAttendeesMailAttribute is not set. So do not export as meeting");
    }
    if (zone != null) {
      final String timezoneId = zone.getID();

      try {
        TimeZoneRegistry registry = TimeZoneRegistryFactory.getInstance().createRegistry();
        timeZone = registry.getTimeZone(timezoneId);
      } catch (Exception rc) {
        final VTimeZone vTimeZone = new VTimeZone();
        timeZone = new net.fortuna.ical4j.model.TimeZone(vTimeZone);
        final int rawOffset = zone.getRawOffset();
        timeZone.setRawOffset(rawOffset);
      }
    }
  }
  /**
   * Fügt die Wiederholungen des übergebenen Appointment-Objekts dem übergebenen
   * Event-Objekt hinzu.
   *
   * @param appointment Ein Rapla Appointment.
   */
  private void addRepeatings(Appointment appointment, PropertyList properties) {
    Repeating repeating = appointment.getRepeating();

    if (repeating == null) {
      return;
    }

    // This returns the strings DAYLY, WEEKLY, MONTHLY, YEARLY
    String type = repeating.getType().toString().toUpperCase();

    Recur recur;

    // here is evaluated, if a COUNT is set in Rapla, or an enddate is
    // specified
    if (repeating.getNumber() == -1) {
      recur = new Recur(type, -1);
    } else if (repeating.isFixedNumber()) {
      recur = new Recur(type, repeating.getNumber());
    } else {
      net.fortuna.ical4j.model.Date endDate = new net.fortuna.ical4j.model.Date(repeating.getEnd());
      // TODO do we need to translate the enddate in utc?
      recur = new Recur(type, endDate);
    }

    if (repeating.isDaily()) {
      // DAYLY -> settings : intervall
      recur.setInterval(repeating.getInterval());

    } else if (repeating.isWeekly()) {
      // WEEKLY -> settings : every nTh Weekday
      recur.setInterval(repeating.getInterval());

      calendar.setTime(appointment.getStart());
      recur.getDayList().add(WeekDay.getWeekDay(calendar));
    } else if (repeating.isMonthly()) {
      // MONTHLY -> settings : every nTh Weekday
      recur.setInterval(repeating.getInterval());
      calendar.setTime(appointment.getStart());
      int weekofmonth =
          Math.round(calendar.get(java.util.Calendar.DAY_OF_MONTH) / DateTools.DAYS_PER_WEEK) + 1;
      recur.getDayList().add(new WeekDay(WeekDay.getWeekDay(calendar), weekofmonth));
    } else if (repeating.isYearly()) {
      // YEARLY -> settings : every nTh day mTh Monthname
      calendar.setTime(appointment.getStart());
      calendar.get(java.util.Calendar.DAY_OF_YEAR);
    } else {
      getLogger().warn("Invalid data in recurrency rule!");
    }

    properties.add(new RRule(recur));

    // bugfix - if rapla has no exceptions, an empty EXDATE: element is
    // produced. This may bother some iCal tools
    if (repeating.getExceptions().length == 0) {
      return;
    }

    // Add exception dates
    // DateList dl = new DateList(Value.DATE);

    ExDate exDate = new ExDate();
    TimeZoneRegistry registry = TimeZoneRegistryFactory.getInstance().createRegistry();
    net.fortuna.ical4j.model.TimeZone tz = registry.getTimeZone(timeZone.getID());

    // rku: use seperate EXDATE for each exception
    for (Iterator<Date> itExceptions = Arrays.asList(repeating.getExceptions()).iterator();
        itExceptions.hasNext(); ) {
      // DateList dl = new DateList(Value.DATE);
      Date date = itExceptions.next();
      // dl.add(new net.fortuna.ical4j.model.Date( date));
      java.util.Calendar cal = raplaLocale.createCalendar();
      cal.setTime(date);
      int year = cal.get(java.util.Calendar.YEAR);
      int day_of_year = cal.get(java.util.Calendar.DAY_OF_YEAR);
      cal.setTime(appointment.getStart());
      cal.set(java.util.Calendar.YEAR, year);
      cal.set(java.util.Calendar.DAY_OF_YEAR, day_of_year);
      int offset =
          (int) (tz.getOffset(DateTools.cutDate(date).getTime()) / DateTools.MILLISECONDS_PER_HOUR);
      cal.add(java.util.Calendar.HOUR, -offset);
      Date dateToSave = cal.getTime();
      net.fortuna.ical4j.model.DateTime dateTime = new net.fortuna.ical4j.model.DateTime();
      dateTime.setTime(dateToSave.getTime());
      exDate.getDates().add(dateTime);
    }
    exDate.setTimeZone(tz);

    properties.add(exDate);
    // properties.add(new ExDate(dl));
  }