A resource-oriented architecture for business process systems

Abstract

Background: The REpresentational State Transfer (REST) design principles treat all concepts in the world as link-connected resources, and support ROA (Resource-Oriented Architecture) for the Web applications. REST and ROA are responsible for the adaptability achieved in the Web. Some design approaches of Web-based business process systems recently evolved towards RESTful to inherit adaptability. However, none of the approaches can improve the adaptability of the produced systems. Aims: Propose a systematic approach for design and execution of Web-based business processes to improve adaptability of the produced systems. Methods: This research followed an empirical research methodology, which evaluates research solutions with real-world cases. On one hand, the research solution was derived by 1) tailoring the REST principles towards business process systems; 2) proposing REST annotations on existing business process modelling; 3) mapping the concepts of business process to HTTP/URI specifications; and 4) designing a format for process context information. On the other hand, the research solution was evaluated through three real-world case studies. Two of the case studies conducted comparative analysis in terms of adaptability of the systems produced by the proposed approach and two alternatives, namely, SOA and MEST (MESsage Transfer). The analysis is based on metrics, including LOC difference, change locality, coupling and cohesion, and an analysis framework called BASE. Results: The research solution is ROA4BP, which includes 1) an architecting approach for design and implementation of Web-based business processes to provide a development guideline; 2) a set of REST-related annotations on existing process modelling to ensure the compatibility with existing techniques; 3) A systematic mapping between business process and HTTP/URI specifications to utilize the advanced mechanisms provided by the Web infrastructure; and 4) a communication format to exchange structured process context information during runtime among process participants. A modelling tool, a programming API and a runtime engine were implemented to support the approach and simplify the implementation of case studies. The case studies demonstrated that ROA4BP can produce more adaptable business process systems compared to the other two alternatives. Conclusion: ROA4BP can help to design and execute RESTful business process systems with better adaptability at design-time and runtime.