Behavioral Substitutability in Component Frameworks: a Formal Approach

When using a component framework, developers need to respect the behavior implemented by the components. Dynamic information such as the description of valid sequences of operations is required. In this paper we propose a mathematical model and a formal language to describe the knowledge about behavior. We rely on a hierarchical model of deterministic finite state-machines. The communication between the machines follows the Synchronous Paradigm. We focus on extension of components, owing to the notion of behavioral substitutability. Our approach relies on compositionality properties to ease automatic verification. From the language and the model, we can draw practical design rules that preserve safety properties. Associated tools may ensure correct and safe reuse of components, as well as automatic simulation and verification, code generation, and run-time checks.