Non-Functional Policies

It is well known that a meta-object protocol (MOP) is a powerful mechanism to control the behavior of an application and to implement non-functional requirements such as fault-tolerance and distributed execution. A key feature of these architectures is the strict separation between the application at the base-level and the non-functional concerns at the meta-level. This makes it possible to develop generic meta-programs that can be reused for many applications. However, an important difficulty with this approach is the expression of application specific policies with respect to non-functional behavior. In this paper, we show a new approach that solves this problem by clearly separating policy from both application and meta-level. In our approach, policies are expressed at a high-level of abstraction as separate strategies. This results in highly reusable meta-programs that take application specific characteristics into account. We have validated our approach in the Correlate prototype.