I am considering using NHapi in some HL7 related projects. Usually when I decide to use any open source library in a project, I have two criteria:
Looking at the NHapi forum on SourceForge, it does not seem to fulfill any of the above two criteria.
The other options are either to buy a commercial product or to write a parser.
Anyone has any suggestion or thoughts of using NHapi ?
We have begun implementing NHAPI in some of our HL7 processing applications. We had the same concerns as you did, but given that it is open source, it is certainly more useful than writing your own parser. Since it and the HAPI project on which it is based are licensed under MPL, you could always fork the codebase if you find the project is not meeting your needs.
We have also used a commercial product whose name I forget, but that has caused its own challenges. The installation and licensing is a challenge, especially on newer operating systems and the company is de-emphasizing the product, so support is very poor.
I have found also that there's at least a little bit of third-party usage out there too: http://dib0.nl/code/255-where-to-begin-if-you-want-to-start-with-hl7-in-c-or-java