Synthesis of component and connector models from crosscutting structural views

Abstract

We present component and connector (C&C) views, which specify structural properties of component and connector models in an expressive and intuitive way. C&C views provide means to abstract away direct hierarchy, direct connectivity, port names and types, and thus can crosscut the traditional boundaries of the implementation-oriented hierarchical decomposition of systems and sub-systems, and reflect the partial knowledge available to different stakeholders involved in a system's design.As a primary application for C&C views we investigate the synthesis problem: given a C&C views specification, consisting of mandatory, alternative, and negative views, construct a concrete satisfying C&C model, if one exists. We show that the problem is NP-hard and solve it, in a bounded scope, using a reduction to SAT, via Alloy. We further extend the basic problem with support for library components, specification patterns, and architectural styles. The result of synthesis can be used for further exploration, simulation, and refinement of the C&C model or, as the complete, final model itself, for direct code generation.A prototype tool and an evaluation over four example systems with multiple specifications show promising results and suggest interesting future research directions towards a comprehensive development environment for the structure of component and connector designs.

Why is My Component and Connector Views Specification Unsatisfiable?

“…Definition 1 (Component and Connector model [13]): A C&C model is a structure m = Cmps, P orts, Cons, T ypes, subs, ports, type where…”

“…Recently, we have presented C&C views [13], as a means to formally and intuitively specify constraints on the structure of C&C models. The views allow engineers to specify constraints on hierarchy and connectivity, using partial examples, while crosscutting the implementation-oriented system/sub-system hierarchy of the target model.…”

“…The verification problem of checking a C&C model against a view was investigated in [14]. The synthesis problem of automatically generating a C&C model satisfying a given views specification, if one exists, was studied in [13].…”

“…This design choice is based on Alloy's readability, which helps us in accelerating our work and in gaining confidence in its correctness. Naively, one would hope to combine the translation of [13] with Alloy's support for UNSAT core [19] and obtain a C&C views core. However, an Alloy core is a minimal set of facts and predicates, while a C&C views core is a minimal set of partial views; the naive approach fails.…”

“…However, an Alloy core is a minimal set of facts and predicates, while a C&C views core is a minimal set of partial views; the naive approach fails. Although the translation of [13] is correct, it is not regular in the sense of [19] and thus the algorithm of [19] sometimes fails to produce C&C views cores based on this translation. We have thus revised and refined the translation from [13] so that the UNSAT core result can be effectively mapped back to the C&C views level.…”