Implementing External Action Blocks › Construction › Customize the Appropriate External Action Logic › External Action Block with Embedded Customized Code

External Action Block with Embedded Customized Code

You can embed the entire subroutine's logic in the External Action Block. The following figure shows the processing flow for an External Action Block that contains the external subroutine logic.

In the following illustration, the calling procedure step ADD_CUSTOMER needs to access the customer history database using an external subroutine. The External Action Block READ_HISTORY defines the views of CA Gen data needed by the imbedded subroutine, and matches them with the views from ADD_CUSTOMER. The External Action Block READHIST is the CA Gen-generated stub modified to include all of the logic for the subroutine. READHIST uses the data passed from the generated procedure step ADDCUST to perform the processing.

After you modify the stub, it becomes the source module for the External Action Block. It must still be compiled and linked before you can install the load module.