Migration from COBOL to SOA: Measuring the Impact on Web Services Interfaces Complexity

SOA and Web Services allow to easily expose business functions to build larger distributed systems. However, legacy systems – mostly in COBOL – are left aside unless applying a migration approach. Main approaches are: direct and indirect migration. The former implies to wrap COBOL programs with a thin layer of a Web Service oriented language/platform. The latter needs reengineering COBOL functions to a modern language/platform. In a previous work, we presented an intermediate approach based on direct migration where developed Web Services are later refactored to improve their interfaces quality. Refactorings mainly capture good practices inherent to indirect migration. In this paper, we measure the complexity of Web Services’ interfaces generated by the three approaches. Both comprehension and interoperability can be affected according to the service interface complexity level. We apply a metric suite (by Baski & Misra) to measure complexity on services interfaces – i.e., WSDL documents. Migrations of two real COBOL systems upon the three approaches were compared on the complexity level of the generated WSDL documents.