Request for a terminal-oriented transaction

Figure 1 shows the data flow for a request that starts a terminal-oriented transaction.

Figure 1. Starting a terminal-oriented transaction—data flow
This illustration shows the data flow when the is used to start a 3270 BMS application. The data flow is described in the text.

This figure shows the data flow through the CICS® business logic interface for a 3270 BMS application.

  1. The caller of the CICS business logic interface provides a COMMAREA that contains the request to be processed. The contents of the COMMAREA must be in a code page acceptable to the subsequent processes, and DFHWBTTA requires EBCDIC.
  2. You can use the Decode function of the converter to modify the request if required.
  3. As this is the first transaction of a conversation or pseudoconversation, the request includes the transaction ID, and perhaps data to be made available to the transaction program. DFHWBTTA extracts the data so that it can be made available to the transaction program in a RECEIVE command.
  4. The transaction program uses a RECEIVE command to receive the data. It then constructs an output map, and uses a SEND MAP command to send it to the requester.
  5. The map and its data contents are converted into HTML. This conversion uses templates defined in DOCTEMPLATE definitions.
  6. You can use the Encode function of the converter to modify the response if required.
  7. The CICS business logic interface returns to its caller, which can now use the contents of the COMMAREA.

Figure 2 shows the data flow for a request that continues a terminal-oriented transaction.

Figure 2. Continuing a terminal-oriented transaction—data flow
This illustration shows the data flow when the is used to continuet a 3270 BMS application. The data flow is described in the text.

This figure shows the data flow when the CICS business logic interface processes the request.

  1. The caller of the CICS business logic interface provides a COMMAREA that contains the request to be processed. The contents of the COMMAREA must be in a code page acceptable to the subsequent processes. Usually this means that they must be in EBCDIC.
  2. The Decode function of the converter constructs the COMMAREA for DFHWBTTA.
  3. As this is not the first transaction of a conversation or pseudoconversation, the request includes HTML corresponding to the map that the transaction program is expecting to receive. DFHWBTTA extracts the forms data to make it available to the transaction program in a RECEIVE MAP command.
  4. The incoming forms input data is converted into a BMS map. This conversion uses templates from DOCTEMPLATE definitions.
  5. The transaction program uses a RECEIVE MAP command to receive the data. It then constructs an output map, and uses a SEND MAP command to send it to the requester.
  6. The map and its data contents are converted into HTML. This conversion uses templates from DOCTEMPLATE definitions.
  7. The Encode function of the converter uses the HTML output from the conversion process to construct the COMMAREA to be returned to the caller.
  8. The CICS business logic interface returns to its caller, which can now use the contents of the COMMAREA.