A Wrapping Approach for Migrating Legacy System Interactive Functionalities to Service Oriented Architectures

Software systems modernisation using Service Oriented Architectures (SOAs) and Web Services represents a valuable option for extending the lifetime of mission-critical legacy systems. This paper presents a black-box modernisation approach for exposing interactive functionalities of legacy systems as Services. The problem of transforming the original user interface of the system into the request/response interface of a SOA is solved by a wrapper that is able to interact with the system on behalf of the user. The wrapper behaviour is defined in the form of Finite State Machines retrievable by black-box reverse engineering of the human–computer interface. The paper describes our wrapper-based migration process and discusses the results of case studies showing process effectiveness and quality of resulting services.