We propose a framework for component-based modeling using an abstract layered model for components. A component is the superposition of two models: a behavior model and an interaction model. Interaction models describe architectural constraints induced by connectors between components. We propose and analyze general requirements for component composition that motivated and guided the development of the framework. We define an associative and commutative composition operator on components encompassing heterogeneous interaction. As a particular instance of the proposed framework, we consider components where behavior models are transition systems and interaction models are described by priority relations on interactions. This leads to a concept of "flexible" composition different from usual composition in that it preserves deadlock-freedom and is appropriate for correctness by construction. Nevertheless, flexible composition is a partial operation. Product systems should be interaction safe in the sense that they do not violate constraints of the interaction model. We propose results ensuring correctness by construction of a system from properties of its interaction model and of its components. The properties considered include global deadlock-freedom, individual deadlock-freedom of components, and interaction safety.
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