The STRING interface contains matched request/response pairs. In most cases the response will be of the same kind as the request, but under certain conditions deviations will be allowed.
As XSD schema can't define workflows of this kind we keep a table of allowed request-response pairs here.
|BookingRequest||PaymentResponse||payment before booking|
|PaymentRequest||BookingResponse||only in case of payment before booking - booking completed|
|PaymentRequest||PaymentResponse||standard case payment after booking|