Migrating Legacy Systems to a Service-Oriented Architecture with Optimal Granularity

The enhanced interoperability of business systems based on Service-Oriented Architecture (SOA) has created an increased demand for the re-engineering and migration of legacy software systems to SOA-based systems. Existing approaches focus mainly on defining coarse-grained services corresponding to business requirements, and neglect the importance of optimising service granularity based on service reusability, governance, maintainability and cohesion. An improved migration of legacy systems onto SOA-based systems requires identifying the ‘right’ services with an appropriate level of granularity. This paper proposes a novel framework for the effective identification of the key services in legacy code to provide such an optimal mapping. The framework focuses on identifying these services (based on standardized modelling languages UML and BPMN) and provides effective guidelines for identifying optimal service granularity over a wide range of possible service types