A Cohesion Measure for Aspects

Aspect-Oriented Software Development is a promising new software engineering paradigm. It promotes, in particular, improved separation of crosscutting concerns into single units called aspects. AspectJ, the most used aspect-oriented programming language, represents an extension of Java. In fact, existing objectoriented programming languages suffer from a serious limitation in modularizing adequately crosscutting concerns. Many concerns crosscut several classes in an object-oriented system. Moreover, several metrics have been proposed in order to assess object-oriented software quality attributes. However, these metrics do not cover the new abstractions and complexity dimensions introduced by the aspect paradigm. As a consequence, new metrics must be developed to assess aspectoriented systems quality attributes. Cohesion is considered as one of the most important software quality attributes. Cohesion refers to the degree of relatedness between members of a software component. We propose, in this paper, a new approach for aspect cohesion measurement based on dependencies analysis. We introduce several cohesion criteria taking into account aspects' features and capturing various dependencies between their members. We also propose a new aspect cohesion metric and compare it, using several case studies, to few existing aspect cohesion metrics.