Contextual Pointcut Expressions for Dynamic Service Customization

In service-oriented environments, components are discovered and integrated at runtime. The type of the client entities that expose potentially interesting contexts can therefore not be anticipated, and can not be subject to type-based pointcut expressions. This paper proposes a contextual pointcut construct that attempts to address context passing mechanisms needed for concurrent customization of services. Contextual pointcut expressions generalize the semantics of ‘cflow’ to enable advices to retrieve a richer set of context information along the call path to a target joinpoint. A context visitor collects information about the particular circumstances in which a target joinpoint is executed, including references to the joinpoints encountered along the path. Contextual advices have the power to alter the control flow of the aspect execution, and return control to the joinpoints that are still alive in the target joinpoint’s call path.