Combining meta information management and reflection in an architecture for configurable and reconfigurable middleware

The last decade has seen the emergence and popularisation of middleware technologies, such as the OMG’s Common Object Request Broker Architecture (CORBA), Microsoft’s Distributed Component Object Model (DCOM) and Sun’s Java RMI. These technologies have profoundly changed the way distributed applications are developed. In particular, they enable the large-scale deployment of applications in distributed heterogeneous environments, by making transparent the distribution aspects and enabling the developers to focus on application concerns. Importantly, the dissemination of distributed systems technology has also stimulated the emergence of new application areas, such as distributed multimedia and mobile applications. However, due to the dynamic nature of these new applications, current middleware technologies have proven inadequate. The major reason for this is the currently dominating “black-box” philosophy for middleware design, which precludes the flexible configuration and adaptation of a platform in order to suit the particular and evolving requirements of different applications. This thesis proposes a solution to these limitations by adopting an open-ended approach to the design of middleware platforms. To this end, a middleware architecture is developed which combines the use of meta-information management techniques, for the definition of customised platform configurations, with objectoriented reflection, which allows the dynamic adaptation of the platform. The integration of the two techniques is based on a well-defined meta-model, which prescribes, in a unified way, the structure and contents of the meta-information handled by both the meta-information management facility and the reflection