Measuring Coupling in Aspect-Oriented Systems

Coupling is an internal software attribute that can be used to indicate the degree of interdependence among the components of a software system. Coupling is thought to be a desirable goal in software construction, leading to better values for external attributes such as maintainability, reusability, and reliability. Aspect-oriented software development (AOSD) is a new technique to support separation of concerns in software development. In aspect-oriented (AO) systems, the basic components are aspects or classes, which consist of attributes (aspect or class instance variables) and those modules such as advice, intertype declarations, pointcuts, and methods. Thus, in AO systems, the coupling is mainly about the degree of interdependence among aspects and/or classes. To test this hypothesis, good coupling measures for AO systems are needed. In this paper, we propose a coupling measure suite for assessing the coupling in aspect-oriented systems. We first present a coupling framework for AO systems which specially designed to count the dependencies between aspects and classes in the systems. Based on this framework, we formally define various coupling measures in terms of different types of dependencies between aspects and classes. We also discuss the mathematical properties of these measures.