Consistent Unanticipated Adaptation for Context-Dependent Applications

Unanticipated adaptation allows context-dependent applications to overcome the limitation of foreseen adaptation by incorporating previously unknown behavior. Introducing this concept in language-based approaches leads to inconsistencies as an object can have different views in different contexts. Existing language-based approaches do not address unanticipated adaptation and its associated run-time inconsistencies. We propose an architecture for unanticipated adaptation at run time based on dynamic instance binding crafted in a loosely manner to asynchronously replace adaptable entities that allow for behavioral changes of objects. To solve inconsistencies, we introduce the notion of transactions at the object level. Transactions guard the changing objects during their execution, ensuring consistent views. This allows for disruption-free, safe updates of adaptable entities by means of consistent unanticipated adaptation

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