Implement 3270 protocol in Java

Question

I've got a big problem with IBM HACL for accessing a server which speaks 3270 protocol. The library keeps crashing, and our JNI wrapper is actually a bug-fixing layer for the poorly-implemented and poorly-documented library (and I suspect we have introduced new bugs with it too). Moreover, in our company, everybody knows Java, and could maintain the software if we didn't have the JNI-Layer and the IBM class library.

We have to use the C++ class library, because the IBM Java library is unusable: we get every non-printable character translated, and we lose all control characters along the way.

Now the question is: can we ditch this library and implement our solution in Java completely (we'd like to avoid using another library from another vendor)? Is the protocol well documented? Is the implementation of 3270-over-ssl really so complex?

Thanks.

Answer 1

http://tools.ietf.org/html/rfc1041

so i guess its documented (assuming i hit the right doc) couldnt find a java implementation though, you'd need to code it over telnet, or maybe SSH

Answer 2

I am unfamiliar with the differences between 3270 and 5250 data streams, but there is a 5250 implementation in Java in the tn5250j project available from http://tn5250j.sourceforge.net/

It might be usable for you?

(also there is a 3270 screen scraping project at http://freehost3270.sourceforge.net/ but it appears to be abandoned).

Answer 3

freehost3270 doesn't look as abandoned as it might appear - CVS has changes from 2 years ago. There is always an arguement that good code won't need to be changed that often in any case if the requirements have not altered. There have been complimentary comments wrt to the codebase. If you don't particularly want to work with other vendors products then working with this code/project seems to be your best option.