Section 8.7. SUMMARY AND FUTURE WORK

8.7. SUMMARY AND FUTURE WORK

We have identified the arbitrariness of the primary model as the most important cause of code tangling. We argued that join point interception is an important foundation for dealing with code tangling but does not alone suffice to cope with the identified problems. We proposed CAESAR, a model for aspect-oriented programming with dedicated support for crosscutting models. CAESAR's strengths are in the reuse and componentization of aspects, allowing us to use aspects polymorphically. We introduced the notion of aspectual polymorphism as a generalization of subtype polymorphism to crosscutting models and proposed a novel concept for dynamic aspect deployment in order to realize aspectual polymorphism. Static type safety is preserved due to the introduction of virtual classes and family polymorphism.

There are a few limitations and further extensions of the model. First, our virtual class mechanism is currently not powerful enough to associate virtual types with other types that are defined outside the enclosing type. This might eventually prove to be too restrictive. We are investigating ways of "importing" external types within a collaboration interface. Second, we believe that the modularity of pointcut specifications can be improved to enhance reuse and incremental definition of pointcuts. Third, similar to other AO approaches, CAESAR builds on top of run-time environments designed with a procedural or object-oriented execution model in mind. We believe that aspect-aware execution models result in more expressive aspect-oriented languages. Last but not least, the concepts in CAESAR are the result of lab research, and their usefulness has to be evaluated in real-life case studies. We are currently involved in a project with software companies aiming at evaluating aspect-oriented concepts, in general, and CAESAR, in particular, in real industrial projects.