Understanding the Example Application’s Data Flow (MQ)

The scenarios presented in this chapter are based on an example customer order and credit inquiry application that is comprised of three programs:

• PDA016 Customer Order Inquiry program
• PDA017 Customer Order Inquiry Processing program
• PDA018 Credit Inquiry program.

The application communicates with a remote application that returns information necessary for PDA018 processing.

In order to understand these testing scenarios, you must understand the application’s data flow. Refer to Flowchart for the Sample Customer Order And Credit Inquiry Application as you read through the following processing description. The circled numbers on the illustration correspond to the following steps.

1. Processing begins with a customer order and credit inquiry request. PDA016 (Customer Order Inquiry Program) receives the request and issues:
   • An MQ_PUT to the MQ Customer Order Inquiry Queue that triggers PDA017 (Customer Order Inquiry Processing Program).
   • An MQ_GET with a wait interval to the MQ Customer Order Inquiry Response Queue to be satisfied when PDA017 completes processing.
   • An MQ_GET with a wait interval to the MQ Credit Inquiry Response Queue to be satisfied when PDA018 completes processing.
2. PDA017 responds to the triggering MQ_PUT from PDA016 and issues an MQ_GET to MQ Customer Order Inquiry Queue.

3. PDA017 locates the customer’s order information and issues:

   • An MQ_PUT to the MQ Customer Order Inquiry Response Queue that answers the MQ_GET from PDA016.
   • An MQ_PUT to the MQ Credit Inquiry Queue that triggers PDA018 (Credit Inquiry Program).

   PDA017 processing is complete.

4. PDA018 responds to the triggering MQ_PUT from PDA017 and issues an MQ_GET to the MQ Credit Inquiry Queue.
5. PDA018 begins processing by issuing:
   • An MQ_PUT to the remote Credit Bureau Inquiry Queue that will drive remote processing.
   • Three MQ_GETs to Credit Bureau Inquiry Response Queue with wait intervals.
6. After the MQ_GETs are satisfied with responses or expire, PDA018 determines credit authorization and issues an MQ_PUT to MQ Credit Inquiry Response Queue, which answers the MQ_GET from PDA016.

Flowchart for the Sample Customer Order And Credit Inquiry Application