OMG_O19 is one of the messages which may be hard to parse unambiguously. The problem lies in the fact that the ORDER_PRIOR group begins with an *optional* ORC segment. So, the sequence ORC TQ1 OBR can be parsed in both ways Søren described it, and there is virtually no means for HAPI to pick the "right" possibility. The dummy BLG in fact disambiguates the parsing. I guess HAPI parsing happens in a "first match" fashion in that it picks the first possibility in a depth-first manner (in this case, the nested group is used instead of the sibling group).
The note stated in the 2.5 spec says that groups defined in later versions must begin with an non-optional segment, but since OMG_O19 has been defined in a previous version. this statement does not apply. As such I don't see a real bug here. This is certainly unsatisfying and there are certainly a whole number of other ambiguities in the HL7 standard as well. Instead of disambiguating dummy segments, here's another possibility: if your OMG_O19 should never contain ORDER_PRIOR groups, you can define a custom message structure along with a custom ModelClassFactory that defines OMG_O19 *without* this group or with mandatory ORC segment at the beginning or whatever is necessary to disambiguate parsing such a message in your case. regards Christian Well, according to the standard - section 4.4.4, it is stated that the BLG segment is optional. I think there might be a bug, in that it seems that the parser does not respect the rule stated at Page 2-7, section 2.5.2: "... *As of v 2.5, the first segment in a newly defined segment group will be required to help ensure that unparsable messages will not be inadvertently defined. ...*" - Which means that a PID segment would have been required if the second ORC should have belonged to the prior results. IMHO, this is a bug in HAPI. Perhaps James Agnew or Christian Ohr would care to comment on this? -- View this message in context: http://old.nabble.com/Handling-HL7-ambiguity-in-OMG-message-tp34600431p34696226.html Sent from the hl7api-devel mailing list archive at Nabble.com. ------------------------------------------------------------------------------ Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov _______________________________________________ Hl7api-devel mailing list Hl7api-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/hl7api-devel
