From COBOL to Models: an MDE framework to extract business logic out of legacy COBOL systems

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© 2009 IBM Corporation

Extracting Business Rules from COBOL:A Model-Based Framework

Valerio Cosentino - IBM, AtlanMod, INRIA & EMN, Nantes - [email protected] Cabot - AtlanMod, INRIA & EMN, Nantes - [email protected] Albert – IBM - [email protected] Bauquel – IBM - [email protected] Perronnet – IBM - [email protected]

WCRE 2013, Koblenz, Germany – 14-17 October

2 © 2009 IBM Corporation

Outline

Introduction– Problem– Running example

Framework overview– Model Discovery– Business Term Identification– Business Rule Identification– Business Rule Representation

Early validation Conclusion & future work


Problem


Problem

Poor/outdated system documentation


Problem

Poor/outdated system documentation The original developers/business analysts may have left the

organization


Problem

Poor/outdated system documentation The original developers/business analysts may have left the

organization Business rules spread in the source code


Problem

Understanding and evolving the business policies together with the corresponding business rules is not trivial


Problem

Understanding and evolving the business policies together with the corresponding business rules is not trivial

Specially true for legacy systems


COBOL

Largely used:– 200 billion lines of code in existence– 70%-75% of business and transaction systems– 90% of global financial transactions


COBOL

Largely used:– 200 billion lines of code in existence– 70%-75% of business and transaction systems– 90% of global financial transactions

Shortage of COBOL developers:– Study on 357 Information Technology professionals

– 46% says they already notice a shortage– 50% says the average age is > 45– 22% says the age is > 55


Running exampleBag

Money

Is open

Need Quantity

Price

Business rules in the program:–If the shop is open, then the customer can buy products–If a product P is needed, then the customer buys P–If the client has enough money, then he can buy products–If the client has enough room in his bag, he can buy products–If a product is available, then it may be bought–If a product is bought, its quantity is decreased by one


Running example Rule embedded in the code:

if a product is bought, its quantity is decreased by one


Framework overview

Model Driven Engineering:– Modular framework– Internal/external representation of BRs– Traceability between rules and source code– Mature tools available for model manipulations, visualizations

and transformations (e.g., ATL, Xtext, ...)


COBOL Model Discovery


Business Term Identification

Manually: the user selects the variables Automatically: heuristic-based strategy




1) Statements are separated in groups:– Conditional– Computational– ...




1) Statements are separated in groups:– Conditional– Computational– ...

2) Variables in statements are classified in:– Condition– Index– Source– Target




– all target variables in computational statements– all variables in conditional statements– ...


Business Rule Identification


Business Rule Identification – Rule Discovery Rule Fragment Identification:


Business Rule Identification – Rule Discovery Rule Context Identification:


Business Rule Representation


Business Rule Representation – Vocabulary Extraction

Optional and manual step


Business Rule Representation – Visualization

Text-based visualization



Text-based visualization



Graph-based visualization


Early validation

Does the framework find complete business rules? Are the extracted rules understandable?


Early validation


Analysis of an IBM COBOL application:– 14 programs– 130 variables– 6500 lines of code

4 internal IBM COBOL experts:– They knew the application– They analysed the business rules generated by our framework


Early validation


Analysis of an IBM COBOL application:– 14 programs– 130 variables– 6500 lines of code

4 internal IBM COBOL experts:– They knew the application– They analysed the business rules generated by our framework

The framework is able to identify the complete business rules– But some extracted rules include technical knowledge


Conclusion and future work

MDE benefits:– Modular framework– Internal/external representation of BRs– Traceability between rules and source code


Conclusion and future work

MDE benefits:– Modular framework– Internal/external representation of BRs– Traceability between rules and source code

Future work:– Complete the early validation on a real system– Extract and unify the rules buried in other layers (presentation,

data, logic)


Questions

From COBOL to Models: an MDE framework to extract business logic out of legacy COBOL systems

Technology

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