Abstract—Service-Oriented Enterprise Architecture requires the efficient development of loosely-coupled and interoperable sets of services. Existing design approaches do not always take full advantage of the value and importance of the engineering invested in existing legacy systems. This paper proposes an approach to define the key services from such legacy systems effectively. The approach focuses on defining these services based on a Model-Driven Architecture (MDA) approach supported by guidelines over a wide range of possible service types.
Keywords - SOEA, Enterprise Engineering, Service-Oriented Enterprise Architectures, Legacy systems, Architecture modelling, Model-Driven Architecture
Service-Oriented Enterprise Architecture (SOEA) is a modern approach to implementing (and re-implementing) software systems as a set of robust and interoperable services. A complete architecture will be based on a structure of resources (e.g. business strategy, business processes, information, software applications and so on) together with their interdependencies. One of the most vital resources is the existing software (i.e. the legacy systems), representing a considerable investment by an underlying business which will frequently rely on the legacy software for many day-to-day business activities. In this paper, legacy systems refer to any none service-based computer programs inherited from previous software systems.
Research in academia and industry has mostly concentrated on developing service wrappers for existing business logic or an incremental migration process consolidating the business logic or (as an alternative) integrating via adapters. The service identification is the first phase of SOA project lifecycle . There has been relatively little research into an effective approach to identifying the right services to be implemented in the SOEA using approaches such as Model Driven Architecture (MDA).
Our research emphasizes the importance of defining the 'right' service because poor design decisions made here can result in compromises affecting the entire service–oriented enterprise. The ‘right’ service is assumed to provide an optimal level of granularity that does not interfere with service design concepts (e.g. loose coupling) and also provides the tradeoffs required by the organisation (e.g. in terms of complexity levels and maintainability). It is also important to appreciate that defining the key services based on legacy systems inevitably requires a compromise between many elements, both technical and non-technical.
In SOEA, the context of a business service is always driven from a business process or function. This means that it is usually appropriate for the business process definition and design to be used in the process of service identification. To support this standard, the OMG has proposed an MDA approach for modeling processes and services based on a platform-independent approach [2, 3]. At the...