Understanding Business logic outputs from AWS Transform for mainframe

7 minute read

Content level: Advanced

This article explains in details the comprehensive business logic outputs generated from legacy mainframe applications using AWS Transform

Introduction

The Business Rule Extraction (BRE) is a powerful feature in AWS Transform for mainframe that can help in understanding and documenting the business logic embedded in the legacy mainframe COBOL application. Using static analysis and specialized mainframe AI Agents, it generates extensive documentation for business users. These documentations can be used as inputs to the forward-engineering process while modernization the mainframe application to AWS.

Submit business logic extraction job

This article mainly focus on explaining the outputs generated from BRE task. To setup and submit the AWS Transform job, refer to the previous article.

Understanding BRE outputs

Once the Extract business logic task completes the details can be viewed by clicking Review business logic extraction results. When setting the configuration before submitting the BRE task you can either select Application level or File level.

Application level: Generates business documents for all business functions, transactions, batch jobs, and files. This selects all of the files in the application. File level: Generates business documents only for files you select from the file table.

Application level generated the business logic documentation for all the mainframe components uploaded in zip file. On the right hand pane you can see the top level Business overview [1] and the Business functions [2] identified. When you expand the Business functions, it will show the Entry Point details [3] & [4] under that specific business function.

An Entry Point here is defined as either - a Batch job with all its associated components like JCL, PROCs, COBOL programs, utility programs, etc. or a CICS transaction with associated COBOL programs, BMS screens, etc.

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You can click on names to view the Summary of the application, Business functions, Entry points, JCLs or Programs.

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Click on the radio button on left of each line item and then click View results to view the details for that component.

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The page will display an Overview [1] and the list of Business Functions [2] with Description. These are same Business Functions listed in main page. You may click the Name of the Business function to see the details of the function.

You can drag the middle bar with white line [4] to adjust the size of split windows.

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From main page you can select the radio button against a Business function and click View results or directly from inside Application details page as mentioned above. It shows a high level Business purpose [1] and the Key capabilities [2] of the Business function. Down under the Components it shows all the Entry-point names along with Type (batch vs transaction), short description and the main COBOL program. Here also you can click on the name of entry-point to view the details.

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Following the same methods as previous, you can view the details of Entry-points.

CICS Transaction Entry-point

When you select a Transaction Entry-point, it will show the Summary [1] and list all the high-level business function [2]. It will also display environmental details like CICS transaction name, database/files used and integrations [3].

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Next, it display how different called COBOL programs within this Transaction Entry-point are linked. A short description of each COBOL program is also provided.

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If the CICS Entry-point has CICS BMS green-screens, in the next section it shows a preview of each of the BMS screens. This is very useful to understand UI used by users for interaction. Use the prev/next [1] buttons to see all the BMS screens. At the bottom it also lists all the data source [2] details.

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COBOL Program details

On the top it provides a Summary [1], details of sub-systems and Key functions [2]. In numbered bullet format it list all the high-level business functions identified [2].

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It provides some complexity details of the COBOL code by listing counts of IF, ELSE, EVALUATE, etc. [1]. Shows details of the total number of business rules extracted and segregation by rule type [2]. Next, lists all the data sources identified in the COBOL program with type and usage details [3].

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Similar to Transaction Entry-point it previews the CICS BMS green-screens.

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Under the BMS preview screen it also shows the fields used in the BMS screen along with a short description and metadata of each field.

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In the COBOL interaction tab, it also provides details with code snippets where in the code the interaction with the BMS screens happen.

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Under Flow diagram, it presents a graphical view of the program flow. For High-level overview [1], the generated chart shows the flow of all key functionalities [3] as was listed under the Summary. The chart boxes contain the number [3] that maps to key functionality. The chart also show where in the flow the interaction with the data sources happen [4]. Use the zoom in/out/reset button [2] to adjust the size of the chart.

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Use the dropdown button [1] to view the flow for a different business functionality. You may also filter business functionalities by typing on the search bar [2].

The business functionalities with sub-indentation number like 1.1, 2.1.1, etc. are sub-functionalities of the parent functionalities. For complex programs where the functionality can not be outlined in a single chart, it is presented as a child functionality.

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The list of business rules identified are listed under the functional flow. You can sort by clicking the arrow-head buttons in each column header. To filter the rules type on the search bar.

The business rules are captured in Behavior-Driven Development (BDD) format using "Given, When, Then" pattern. The rules can be easily converted to user stories for actionable items during modernization.

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For each set of rules identified it also shows the code snippets from where the rules are extracted. This is helpful for cross validation. Note the high-level overview chart has no supporting code.

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Batch Entry-point

When you select a Batch Entry-point, it will show the Summary [1] and the business function [2]. It will also display environmental details like database and files used, utilities used and integrations.

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Next, it will show the flow of the JCL and details of the Data sources used.

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JCL details

On the top it provides a Summary [1] and Key functions [2]. It provides some details of the JCL - like number of steps, count of PROCs, COND or IF statements used [3]. Shows details of the total number of business rules extracted and segregation by rule type [4]. Next, lists all the data sources identified in the JCL with type and usage details [5].

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