A Rigorous Model of Service Component Architecture

The Service Component Architecture (SCA) provides a platform-independent component model for serviceoriented development. A service component with different communication mechanisms and implementation languages can be modeled in SCA. However, it lacks a formal foundation for SCA-based system specification and verification. This paper presents a formal service component signature model with respect to the specification of the SCA assembly model. Inspired by the idea of independence in SCA, a language-independent dynamic behaviour model is proposed for specifying the interface behaviour of the service component by port activities. Based on the dynamic behaviour model, the compatibility relation between components is discussed. A set of transition rules are given to map Business Process Execution Language for Web Services (BPEL) to dynamic behaviour expressions and then to Petri nets, thus the service component based system can be verified with existing tools. A case study is demonstrated to illustrate how to use our approach to constructing a web application in a rigorous way.