Bounding component behavior via protocols

We enhance the SOFA Component Description Language with a semantic description of a component's functionality. There are two key requirements this description aims to address: first, it should ensure correct composition of the nested architectural abstractions (for design purposes); second, it should be easy-to-read so that an average user can identify a component with the correct semantics for the purposes of component trading. The semantic description in SOFA expresses the behavior of the component in terms of behavior protocols using a notation similar to regular expressions which is easy to read and comprehend. The behavior protocols are used on three levels: interface, frame, and architecture. The key achievements of the paper include the definition of the protocol conformance relation. Using this relation, the designer can in most cases statically verify that the frame protocol adheres to the requirements of the interface protocols, and that the architecture protocol adheres to the requirements of the frame and interface protocols.