Open Aspects

Open Aspects are our approach to face unplanned changes in systems that are based on aspect-oriented composition at runtime. They support explicit adaptation models, allowing developers to describe system change events to be observed, and corrective actions to be taken. These events and actions cover both the base system affected by aspects as well as the aspects affecting the base system themselves. The proper combination of change events and corrective actions allows for conditional just-in-time runtime re-composition. This paper offers a detailed discussion of difficulties related to change in aspect-oriented systems and a description of consistency constraints inherent to them. An implementation illustrating Open Aspects and their application is provided.