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 figure shows the data flow through the CICS® business
logic interface for a 3270 BMS application.
- 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.
- You can use the Decode function of the converter to modify
the request if required.
- 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.
- 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.
- The map and its data contents are converted into HTML. This conversion
uses templates defined in DOCTEMPLATE definitions.
- You can use the Encode function of the converter to modify
the response if required.
- 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 figure shows the data flow when the CICS business
logic interface processes the request.
- 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.
- The Decode function of the converter constructs the COMMAREA
for DFHWBTTA.
- 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.
- The incoming forms input data is converted into a BMS map. This
conversion uses templates from DOCTEMPLATE definitions.
- 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.
- The map and its data contents are converted into HTML. This conversion
uses templates from DOCTEMPLATE definitions.
- The Encode function of the converter uses the HTML output
from the conversion process to construct the COMMAREA to be returned
to the caller.
- The CICS business logic interface returns to its
caller, which can now use the contents of the COMMAREA.