Department of Computer Science & Engineering

After more than a decade of research into and practical application of service-orientation (SO*) there is still confusion about what services are, and what their benefit to Software Engineering research and practice is. Nevertheless, and unfazed by its fuzzy backdrop, SO* has taken hold across industry as the foundation on which large software systems are built. Clearly, this leaves many fundamental questions on the table. This paper focuses on developing the principles and practices for using SO* in large-scale service integration. We start from a simple premise: services are functions, service-oriented architectures (SOAs) are dynamic functional programs. We develop this premise into a semantic foundation for services and SOAs based on a novel dynamic model of stream processing functions. We introduce Open Rich Services (ORS), an architecture pattern for SOA that (a) disentangles infrastructure-concerns cleanly from application-specific concerns, (b) supports flexible and dynamically changeable service composition, and (c) facilitates hierarchical service decomposition. We establish the link between ORS and our basic SOA semantics to yield a comprehensive and scalable SOA foundation. As a proof of concept we develop a domain specific language (DSL) for specification of SOAs following this semantic approach.

Pre-2018 CSE ID: CS2012-0982