Aspects that trigger on a sequence of join points instead of on a single join point are not explicitly supported in current AspectOriented approaches. Explicit protocols are however frequently employed in Component-Based Software Development and business processes and are as such valid targets for aspect application. In this paper, we propose an extension of the JAsCo aspect-oriented programming language for declaratively specifying a protocol fragment. The proposed pointcut language is equivalent to a finite state machine. Advices can be attached to every transition specified in the pointcut protocol. Furthermore, the complement of a protocol can also be used for triggering aspects. The JAsCo tools support the stateful aspects language and implement it very efficiently by employing the JAsCo run-time weaver. As a validation of the approach, we present a case study in the context of reaction business rules.