With the rapid increase in complexity of software systems and applications, it becomes necessary to develop tools to simplify the incorporation of self-managing features into applications. The use of object and component technologies, together with a policy system which externalizes business logic from an application, plays an important role in enabling systems with greater manageability and variability.
Current policy systems are mainly domain specific, and there is a need for an execution system which is flexible and usable across a variety of domains. Our policy execution system provides a framework which utilizes object and component technologies to separate the process of executing a policy into various components and processes. Each component and sub-process can be developed independently, configured and reused.
In our programming system, an episode of policy execution can be viewed as a composition of the following components: high level policy language definition and authoring, translation to executable code for the choice of execution mechanism, input and output, mappings of application objects and the underlying execution mechanism (rule engines, execution algorithms or strategies). Furthermore, we separate a high level policy into its various logic components: operation logic, priority logic, conflict resolution logic and each of these components can be developed and reused independently.
Our policy framework completely hides the programming details and exposes the interfaces only. In the demo, we will show how to build an application using the policy framework in various contexts with a single policy and modify the policy subsequently to illustrate the various operation of each of the components and features, and how an application uses the policy system to enhance its self-managing features. (The prototype of this system will be available for free download in 3Q of 2003.)