An Empirical Study on Refactoring Objects to Aspects

It has been proclaimed in the literature that AOP allows obtaining better modularized systems than those built with OOP, namely by reducing tangling and scattering. Very few quantitative studies sustaining that claim were published. None is known to contradict it. We briefly describe an assessment process that allows performing paradigm-independent modularity assessments, based on a metamodel driven approach, and a set of paradigm-independent metrics. We use this assessment process upon the 23 GoF design patterns that were refactored from Java to AspectJ. We then perform a set of statistical tests to answer some important research questions on the effect of refactoring on overall coupling, cohesion and modularity.