Implementing Completion of a Request

The general mechanism for executing requests for subsystems that have an OPCA entry coded in their MESSAGES/USER DATA policy item is as follows:

  1. The request (with one or two optional parameters) and the job name of the TWS operation are passed to TWS Automation.
  2. TWS Automation identifies the SA z/OS definition of the subsystem through the job name of the TWS operation.
  3. TWS Automation retrieves the expected result, the timer interval, and possibly a timer name, for the respective request/parameter combination from the OPCA entry of the subsystem.
  4. TWS Automation then checks if an OPCAPARM entry is present and if that entry contains a timer module name.
  5. If a timer module is specified, TWS Automation sets the timer with this timer module. Otherwise, it uses a standard timer module (EVJESPTE).
  6. TWS Automation issues the command that is specified in the OPCACMD entry.

After the command has been issued, two things remain to be done:

  • If the command was executed successfully, the TWS control information for this subsystem must be updated.
  • The (positive or negative) result of the request must be posted back to TWS.

How this is done depends on the type of command specified in the OPCACMD entry.