public Response addFlight(JAXBElement<Reservation> reservation) {
DAO db = DAO.getInstance();
ResponseBuilder builder = null;
Reservation addNewReservation = reservation.getValue();
Long ReservationId = addNewReservation.getId();
/* if the Xml file contains all the req fields and it has a reservation
* number and it's the same like the one in the link then it can be updated
*/
if (isReservationContentCorrect(addNewReservation)
&& ReservationId != null) {
if (!db.existReservation(ReservationId)) {
db.addReservation(addNewReservation);
URI reservationUri = uriInfo.getAbsolutePathBuilder().
path(addNewReservation.getId().toString()).
build();
builder = Response.status(Response.Status.CREATED).
location(reservationUri).
entity(HandlingMessage("Success", "success",