A Formal Framework for Scalable Component-Based Systems

Constructing systems from components and building components for different systems require well-established methodologies and processes. This article proposes a formal framework for designing and specifying component-based systems (CBS). The two-dimensional evolutions of CBS are architectural reconfiguration and behavioral adaptation, when user requirements and/or runtime contexts change. This framework provides an incremental design methodology where component interfaces and their corresponding ports are the basic units of software construction, rather than components. Conceptually, interfaces serve to assemble simple components to obtain more complex ones. Behaviorally, they serve to propagate side effects of visible changes of a component on its neighbors. Interfaces also supply interactions and synchronization effects on the underlying sub-system. The calculation process is guided by changes on interfaces where the hierarchical structure of the underlying CBS is maintained. In this framework, CBS specification is supported by some execution tools based on Maude.