ESS Data Flow Using CICS API

Define the event services environment by specifying the types of event data your application receives. These definitions are the event data requests that you issue through the DGAQ247 program or a user-written program.

After you define the event data requests for the client application and activate the request by issuing the EVENT SERVICES START command, ESS processes the event data as follows:

  • Upon receiving the EVENT SERVICES START ID parameter, the API (DGAQ012) passes the command to the DTF through a VTAM session.

    When a requested event occurs, the DTF sends the event data to the API for distribution to the Transient Data Queue (TDQ).

  • The event data is then available to the client application through the DGAQ249 Sample Program. The DGAQ249 program provides a way to read event data from the TDQ and processes the data for use by your application.

    The following diagram illustrates the flow of event data from the DTF to the client application: