Using the CICS business logic interface to run a terminal-oriented transaction

Figure 1 shows the control flow through the CICS® business logic interface for a request for a terminal-oriented transaction. Note that the business logic interface is running under a CICS mirror transaction, not a Web CICS transaction. The first part of the processing is the same as for calling a program, but if you want to run a transaction, you must specify DFHWBTTA as the CICS application program to be called, in wbbl_server_program_name.

Figure 1. Running a transaction with the CICS business logic interface—control flow
Running a transaction with the —control flow
  1. If the caller requests a converter, the CICS business logic interface calls it, requesting the Decode function. Decode sets up the COMMAREA for DFHWBTTA.
  2. The CICS business logic interface calls DFHWBTTA. The COMMAREA passed to DFHWBTTA is the one set up by Decode. If no converter program was called, the COMMAREA contains the entire request.
  3. DFHWBTTA extracts the transaction ID for the terminal-oriented transaction from the HTTP request, and starts a transaction that runs the CICS Web bridge exit.
  4. When the program attempts to write to its principal facility, the data is intercepted by the CICS Web bridge exit. The exit constructs the HTML response which is returned to the CICS business logic interface. If the caller requested a converter, the CICS business logic interface calls the Encode function of the converter, which uses the COMMAREA to prepare the response. If no converter program was called, the CICS business logic interface assumes that the COMMAREA contains the desired response.