private void refreshModel(DefaultListModel model) {
        if (model.equals(guestModel)) {
            ArrayList<Guest> guestList;
            guestList = ctr.getGuestsFromDB();
            guestModel.clear();
            for (int i = 0; i < guestList.size(); i++) {
                guestModel.addElement(guestList.get(i));
            }
            guestJList.setModel(guestModel);
            guestJList2.setModel(guestModel);
        }

        if (model.equals(bookingDetailModel)) {
            bookingDetailModel.clear();
            ArrayList<Guest> roomGuestList;
            roomGuestList = ctr.getBookingDetailsFromDB(ctr.getCurrentBooking());

            for (int i = 0; i < roomGuestList.size(); i++) {
                bookingDetailModel.addElement(roomGuestList.get(i));
            }
            bookingDetailsJList.setModel(bookingDetailModel);
        }
    }