Flexible Persistence Framework for Object-Oriented Middleware

The ability to store object states persistently in a convenient and flexible way is an important requirement for middleware environments. In this paper we propose a language independent framework for flexible and extensible persistent storage services for object-oriented middleware. The framework is specified by interface definitions and the rationale of their interplay. To support application-specific requirements like particular data repositories and distribution aspects, different persistence services are feasible within the proposed framework. These services are easy to use, since objects are stored persistently by inheriting from a single class; additional auxiliary classes–like, for instance, factory or session classes in related approaches–are not required. We remark that inter-object transactional behavior is not in the scope of a persistent storage service; these issues are addressed by transactional services. To show the open design of the proposed framework, we sketch how the framework can be integrated with the Transaction Service proposed by the Object Management Group.