MessageVerication
Messageverication begins with reading the message from the external system. The message is
expectedto match the MLLP envelope, since both HLLP and MLLP envelopes have the Start of
Block(SOB), End of Data (EOD), and a Carriage Return (CR) in common.
Ifa message fails the read verication, it is considered bad data. If read by an inbound Adapter,
thisfailure causes the Adapter to generate a Canned HL7 NAK. An outbound Adapter ignores
themessage and logs a warning, reporting the nature of the problem to the log le.
AnHLLP envelope needs further verication as to whether it is data or a NAK, as well as the
BlockChecksum and Block Size. The Adapter behaves as described above if the HLLP envelope
vericationfails.
Afterstripping the message envelope, the RA hands the de-enveloped message to the inbound
Collaborationwhere it is parsed into the generic event Message Library. This ensures that the
generalform and MSH segment are valid. If the MSH property is set, the Collaboration veries
thatthe elds specied in the HL7 segment section are the same as those of the received MSH,
otherwise,a NAK is returned.
AcknowledgmentProcessing
■AdapterGenerates HL7 Acknowledgment
Inthis scenario, the Adapter generates an HL7 ACK after receiving and successfully storing
themessage in a queue; otherwise, it generates an HL7 NAK. The HL7 ACK or NAK is
placedin the proper envelope and sent to the external system.
■ESBSends HL7 Acknowledgement
Inthis scenario, the Adapter acts as a receiver in a Delayed ACK scenario, as described in
“InboundReceiver Message Mode” on page 15.
■CannedHL7 NAK
Acanned HL7 NAK is created when a read error occurs or when an message cannot be
identiedas an HL7 message. The initial test ensures that the message conforms to the
lower-layerprotocol. The Resource Adapter uses the MSH section parameters to create an
appropriateNAK.
RecourseActions
Recourseactions can be congured for an inbound Adapter for the following conditions. For
moreinformation, see “Recourse Actions” on page 21.
■Theempty read limit is reached.
■Themaximum number of NAKs are received by the Adapter.
■Themaximum number of NAKs are sent by the Adapter.
■Themaximum number of response timeouts is reached.
■ANAK response is received.
SunAdapterfor TCP/IP HL7 Overview
SunAdapterfor TCP/IP HL7 User's Guide • Oc tober 200916