Framework-Specific Modeling Languages

Framework-specific modeling languages (FSMLs) help developers build applications based on object-oriented frameworks. FSMLs formalize abstractions and rules of the framework's application programming interfaces (APIs) and can express models of how applications use an API. Such models, referred to as framework-specific models, aid developers in understanding, creating, and evolving application code. We present the concept of FSMLs, propose a way of specifying their abstract syntax and semantics, and show how such language specifications can be interpreted to provide reverse, forward, and round-trip engineering of framework-specific models and framework-based application code. We present a method for engineering FSMLs that was extracted post-mortem from the experience of building four such languages. The method is driven by the use cases that the FSMLs under development are to support. We present the use cases, the overall process, and its instantiation for each language. The presentation focuses on providing concrete examples for engineering steps, outcomes, and challenges. It also provides strategies for making engineering decisions. The presented method and experience are aimed at framework developers and tool builders who are interested in engineering new FSMLs. Furthermore, the method represents a necessary step in the maturation of the FSML concept. Finally, the presented work offers a concrete example of software language engineering. FSML engineering formalizes existing domain knowledge that is not present in language form and makes a strong case for the benefits of such formalization. We evaluated the method and the exemplar languages. The evaluation is both empirical and analytical. The empirical evaluation involved measuring the precision and recall of reverse engineering and verifying the correctness or forward and round-trip engineering. The analytical evaluation focused on the generality of the method

Clafer: Lightweight Modeling of Structure, Behaviour, and Variability

Embedded software is growing fast in size and complexity, leading to intimate mixture of complex architectures and complex control. Consequently, software specification requires modeling both structures and behaviour of systems. Unfortunately, existing languages do not integrate these aspects well, usually prioritizing one of them. It is common to develop a separate language for each of these facets. In this paper, we contribute Clafer: a small language that attempts to tackle this challenge. It combines rich structural modeling with state of the art behavioural formalisms. We are not aware of any other modeling language that seamlessly combines these facets common to system and software modeling. We show how Clafer, in a single unified syntax and semantics, allows capturing feature models (variability), component models, discrete control models (automata) and variability encompassing all these aspects. The language is built on top of first order logic with quantifiers over basic entities (for modeling structures) combined with linear temporal logic (for modeling behaviour). On top of this semantic foundation we build a simple but expressive syntax, enriched with carefully selected syntactic expansions that cover hierarchical modeling, associations, automata, scenarios, and Dwyer's property patterns. We evaluate Clafer using a power window case study, and comparing it against other notations that substantially overlap with its scope (SysML, AADL, Temporal OCL and Live Sequence Charts), discussing benefits and perils of using a single notation for the purpose