Uniting global and local context behavior with context Petri nets

Context-oriented programming enables adaptation of systems to their execution environment. Behavioral adaptations are defined in the system and then associated to a context. Such adaptations are made available at runtime when their context is deemed more appropriate by the execution environment. Context activation is reified using two techniques. Global to all running threads in the system, or local to a particular thread of execution. Providing one technique or the other may hinder the adaptable capabilities of the system. This paper extends the context Petri nets model to unify global and local context behavior. Global and local context behavior are represented as multicolored tokens in context Petri nets, by assigning a color to each thread in the system. By means of context Petri nets, context-oriented systems can unambiguously adapt their behavior globally, or to a particular thread of execution.