Connecting to CICS from Windows Desktop Application

Question

Now there is a new requirement. I have got some adhoc work at hand. The requirement is to connect a desktop based Java application to read data from Mainframe generated by some CICS Transaction. [Basically I have to read all the records being appended into a file (same way as we do tail-f filename in linux). This is just for FYI my requirement is something different.]

I inquired, and came to know that my employer cannot provide MQ or CICS Transaction Gateway access to me. He suggested some method of screen scraping. I have already done that using VB.Net application and Quick3270 as well as IBM Communicator Emulators. Both these emulators provide functions which can be used to read whatever is there on the screen.

You can refer to EHILLAPI programming details (Language for Emulator programming) - http://publib.boulder.ibm.com/infocenter/pcomhelp/v5r9/index.jsp?topic=/com.ibm.pcomm.doc/books/html/emulator_programming07.htm if you are interested in learning.

But this method is restricting me to the maximum number of bytes that can come on the screen. With this method there is significant network delay as I have to refresh (basically move from one page to another on CICS) everytime to get data which is spanning across multiple pages.

Can you suggest me some method so that the my employer does not need to ask the client to open any port on his Mainframe or install any software (as this is not possible for my employer).

Can I use the 3270 terminal emulation and retrieve all (or at least more data). This way the requirement of my employer is fulfilled and he does not need to ask anything to his client. (In any case from the emulator we are firing CICS Transactions). We want everything to be done at my employer's end itself without disturbing the client's Mainframe even a single bit.

Please do not suggest MQ as the client does not have it.

If you are still suggesting CICS Transaction Gateway, then please let me know how would I connect to the remote machine (I need technical details).
- What information do I need to ask from the client.
- What software do I need to install on my machine. - Technical details of using that software.

Regards,

Nitin

Answer 1

I have two suggestions for you to look at. I have done both successfully. Your client setup can decide if either is palatable (the question doesn't mention not doing these things).

1. You can call your CICS code on the mainframe via a DB2 stored procedure. There is a standard one supplied by IBM called EXECCICS that we used for a project. You supply the standard CICS parameters and comm area. The stored procedure executes the program in the mainframe and returns you the comm area. You use JDBC. This solution is simple and easy the execute.

2. We have also enabled HTTP access to the CICS program on the mainframe. To my understanding (remember I just called it -- not enabled it) it is a pretty standard configuration. The client code just performs an HTTP POST to a specific end point. The resulting document is the comm area plus other goodies.

These solutions were developed independently for the same project and are both in production. The only reason the HTTP method was added to the mix was because of a data size limit in the stored procedure that HTTP removed.