Aspect-Oriented System Coupling Metric and its Validation

Background: Aspect-oriented programming promises to enhance the extensibility and reusability of code through the removal of tangled and crosscutting code. Determining the degree of coupling for Aspect- Oriented Systems (AOSs) would assist in the quantification of various software attributes and hence improve quality. Objective: The research aims to present a novel Aspect-oriented System Coupling Metric (COAO), that calculates the coupling for the complete aspect-oriented system as a whole, based on the properties of elements and the relationships among them. Methods: The process of defining a metric essentially requires a clear, unambiguous definition of primary and relevant concepts related to Aspect-Oriented Programming. As such, first and foremost, novel definitions of basic concepts such as system, element, relation, module, and attribute are specified concerning Aspect- Oriented Programming. Subsequently, a metric for Aspect-Oriented System Coupling is proposed. Subsequently, the proposed metric is validated theoretically against Braiand properties for coupling of software systems. Finally, an illustration for calculation of the proposed metric is demonstrated using an exemplary aspect-oriented system. Results: The findings reveal that the proposed Aspect-Oriented Coupling metric conforms to the five Property- Based software engineering measurements given by Braiand et al. for coupling. This indicates that the proposed metric for the Aspect-oriented System Coupling metric COAO is a valid metric for measuring coupling in Aspect-oriented Software Systems. Conclusion: Results of validation along with the supportive illustration show that single metric to assess coupling for the complete Aspect-oriented Software System is theoretically sound and also easies the calculation of coupling of a software system.