protected override bool isValid(out string exceptionMessage)
{
if (distance <= 0) {
return makeExceptionMessage (out exceptionMessage, "The distance between the locations is invalid");
}
LocationRequest lr = new LocationRequest ();
if (lr.fetchLocationFromAirports (start_airport, destination_airport).Count () != 0) {
return makeExceptionMessage(out exceptionMessage, "There is already an traject between the given airports");
}
return validAirport(start_airport, out exceptionMessage) && validAirport(destination_airport, out exceptionMessage);
}
