On using pre and postconditions to tackle the aspect scheduling problem by rewriting systems: a design-level approach.

Abstract

The aspect-oriented paradigm promises separation of crosscutting concerns by modularizing them as aspects. This paradigm allows then weaving aspects upon some points in the base system. Unfortunately, the interaction of aspects may have an undesirable effect on each other and/or on the base system if they are executed in any order. Many works tried to solve this problem but the proposed solutions were either limited to some simple models of aspects or used to check if a set of temporal properties is preserved when aspects are introduced. In this paper, we propose a framework based on extended UML diagrams (class and state/transition diagrams) in order to make the detection of undesirable interaction more powerful and realistic. This framework relies on finite state automata (FSA); it transforms the interaction problem into a reachability issue. In fact, bad interaction is expressed as a generic LTL property which is independent of the system to be verified. This property can be checked using any model-checker like Maude. To concretize the proposed framework, we propose a rewriting system that allows an implicit construction of the FSA of the base system and the aspects in addition to the aspects composition and the weaving mechanism. Therefore, the proposed system defines a translation scheme of UML models into rewriting logic specifications written in Maude language. Thanks to the advances of the on-the-fly technique in Maude, the use of its LTL model-checker avoids a systematic exploration of all possible combinations of the aspects. The approach will be illustrated by a case study in order to explain how it works.