From Static Methods to Role-Driven Service Invocation - A Metamodel for Active Content in Object Databases

Existing object databases define the behaviour of an object in terms of methods declared by types. Usually, the type of an object is fixed and therefore changes to its behaviour involves schema evolution. Consequently, dynamic configurations of object behaviour are generally not supported. We define the notion of role-based object behaviour and show how we integrated it into an existing object database extended with a notion of collections to support object classification and role modelling. We present a metamodel that enables specific services to be associated with objects based on collection membership and show how such a model supports flexible runtime configuration of loosely coupled services.