I have a vendor that is sending an HL7 message. But when I asked for more detail about their mapping tables, they told me they typically don't supply that but supply an API for customers to call so they don't have to define tables and it is more dynamic.
So with that being said I am creating my first REST operation. I understand the gist of how a REST operation works in working with other types out Non HL7 Operations (SOAP, SQL) before. You send a request and get a response back, that part I understand.