On the Dominance of Decompositions in Models and their Aspect-Oriented Implementations

Aspect-oriented approaches have commonly advocated separation of concerns. Some approaches have applied this separation in a symmetric fashion, like Hyper/J, whereas some others have relied on asymmetric separation, like AspectJ. The difference in the approaches is that the different concerns play a symmetric role in the former, whereas the latter explicitly includes a conventional implementation on top of which other concerns are woven onto as aspects. The question then arises, how are the concerns of the conventional implementation special in the latter, and will the opportunity to use symmetric separation lead to a fundamentally different decomposition. In this paper, we discuss the dominance in decompositions in specifications and corresponding aspect-oriented implementations. As examples, we use the specification method DisCo which allows modeling of concerns in a fashion that separates the different concerns to specification branches, and aspect-oriented implementations using Hyper/J and AspectJ that can be composed for DisCo specifications. As the final outcome, we propose that any aspect-oriented approach addressing the system at the level of program code necessarily has some concerns that are more dominant than some others due to the control flow of programs.