Dynamic Coupling Measurement For Aspect-Oriented Software

Aspect-oriented programming (AOP) is a new technique that packages the behavior which impacts multiple classes into a reusable module. It eliminates the code tangling and scattering caused by object-oriented programming (OOP). The code is more readable and easier to maintain. With the gradual perfection of AOP, coupling measurement for aspect-oriented (AO) software could help to accurately locate the design defects resulting from the over-high coupling of modules. Coupling is an internal software attribute that can be used to indicate the strength of association established by a connection from one module to another. Low coupling is a main tenet in the measurement of high-quality modular software. A common way to define and measure coupling for AO software is through structural properties and static code analysis. However, because of dynamic binding and the common presence of unused aspect code, the resulting coupling measures are imprecise as they do not perfectly reflect the actual coupling taking place among aspects and/or classes at runtime, which brings opportunities and challenges to the AOP dynamic coupling measurement.How coupling can be defined and precisely measured through dynamic analysis of AO systems written in AspectJ based on the analogous theories of OOP are described in this paper. Firstly, a coupling framework for AO systems is specially designed to dynamically count the dependencies between aspects and classes in the systems. Secondly, based on this framework, a coupling measure suite for dynamic assessing the coupling in AO software is proposed. The mathematical properties of these measures are also discussed to show measures satisfy the properties that a good coupling measure should have. Lastly, a dynamic coupling metrics collection tool for AO programs, ADCMT (AOP Dynamic Coupling Measurement Tool), has been designed and implemented in this paper. The detailed solution of dynamic coupling measurement for AO software in this paper is proposed for the first time. With good usability and extensibility, ADCMT is the first tool dealing with dynamic coupling analysis for aspect-oriented programs.