Modular Reasoning with Join Point Interfaces
Milton Inostroza, Éric Tanter, Eric Bodden · 2011
In current aspect-oriented systems, aspects usually carry, through their pointcuts, explicit references to the base code. Those references are fragile and give up important software engineering properties such as modular reasoning and independent evolution of aspects and base code. A well-studied solution to this problem consists in separating base code and aspects using an intermediate interface abstraction. In this work, we show that previous approaches fail at restoring modular reasoning because they do not provide modular type checking; programs can fail to compose when woven, even though their interfaces are compatible. We introduce a novel abstraction called Join Point Interfaces, which, by design, supports modular reasoning and independent evolution by providing a modular type-checking algorithm. Join point interfaces further offer polymorphic dispatch on join points, with an advice-dispatch semantics akin to multi-methods. As we show, our semantics solves important problems present in previous approaches to advice dispatch. We have fully implemented join point interfaces as an opensource extension to the AspectBench Compiler. A study on existing aspect-oriented programs of varying sizes and domains supports our major design choices and reveals potential for exploiting polymorphism through non-trivial join-point type