Design of the Credit Check sample on z/OS

This section describes the design of each of the programs that make up the Credit Check sample application.

For more information about of some of the techniques that were considered during the design of the application, see Design considerations for the Credit check sample on z/OS.

Figure 1 shows the programs that make up the application, and also the queues that these programs serve. In this figure, the prefix CSQ4SAMP has been omitted from all the queue names to make the figure easier to understand.

• User interface program (CSQ4CVB1) on z/OS
  When you start the conversational-mode CICS transaction MVB1, this starts the user interface program for the application.
• Credit application manager (CSQ4CVB2) on z/OS
  The Credit Application Manager (CAM) program performs most of the processing for the Credit Check application.
• Check-account program (CSQ4CVB3) on z/OS
  The checking-account program is started by a trigger event on queue CSQ4SAMP.B3.MESSAGES. After it has opened the queue, this program gets a message from the queue using the MQGET call with the wait option, and with the wait interval set to 30 seconds.
• Distribution program (CSQ4CVB4) on z/OS
  The distribution program is started by a trigger event on queue CSQ4SAMP.B4.MESSAGES.
• Agency-query program (CSQ4CVB5/CSQ4CCB5) on z/OS
  The agency-query program is supplied as both a COBOL program and a C program. Both programs have the same design. This shows that programs of different types can easily coexist within an IBM MQ application, and that the program modules that make up such an application can easily be replaced.

Parent topic: The Credit Check sample on z/OS