Program link server adapter processing

When the program link server adapter DFHMASDP is invoked during request processing, the flow navigator passes the details of the distributed programming link to the server adapter in BTS data-containers.

DFHMASDP runs by default under the CMAS transaction and performs a program link to a target application using the EXEC CICS LINK command. DFHMASDP can pass the data in a COMMAREA that can be up to 32 767 bytes in length or by using a channel and containers. The target application might be in the same region or in a remote region.

The flow navigator passes a number of data-containers to DFHMASDP that store the data that is specified by service flow project tools when the link is modeled. The number of data-containers depends on whether the program link has been modeled to use a COMMAREA or a channel.

Program links that use a COMMAREA
The flow navigator puts the data to be passed in the COMMAREA in the COMMAND.INPUT data-container. The flow navigator puts the description of the program link itself in the DPL.DATA data-container. DFHMASDP uses the data in COMMAND.INPUT to populate the COMMAREA and issues an EXEC CICS LINK command to the target application.
When DFHMASDP receives a response from the application in a COMMAREA, it stores the data in the COMMAND.OUTPUT data-container and the state information in the COMMAND.STATUS data-container.
Program links that use a channel
The flow navigator creates BTS data-containers of the same name and with the same content as every container that is required on the channel. The flow navigator puts the name of the channel, the name of each container, and the number of containers in the DPL.DATA data-container. The default channel name is DFHMA-DPL-CHNL. You can override the default channel name in service flow project tools. DFHMASDP uses the information in DPL.DATA to create the channel and the information from the BTS data-containers to create each container and put it on the channel.
When DFHMASDP receives a response from the application on the channel, it updates the COMMAND.OUTPUT and COMMAND.STATUS data-containers. In addition, DFHMASDP copies each container on the channel to a BTS data-container of the same name. If any required containers are missing or if there is a problem copying the container, DFHMASDP issues an error message and returns to the flow navigator.

If the target application runs in a different region from the CICS Service Flow Runtime, the target application program runs under CSMI, the default mirror transaction ID. You can optionally specify a different transaction in service flow project tools. If you do specify a different transaction, ensure that it is defined in CICS® to invoke the DFH$MIRS mirror transaction program.

If the target application includes any DB2® calls, you must configure the transaction under which the target application runs, whether this is CMAS, CSMI, or your own transaction, as follows:

  1. Create the necessary DB2TRANS or DB2ENTRY resource definitions for the transaction.
  2. Grant access authority in DB2 and RACF® as appropriate.