A Survey of Adaptive Middleware

Developing distributed applications is a difficult task due to three major problems: the complexity of programming interprocess communication, the need to support services across heterogeneous platforms, and the need to adapt to changing conditions. Traditional middleware (such as CORBA, DCOM, and Java RMI) addresses the first two problems to some extent through the use of a “black-box” approach, such as encapsulation in object-oriented programming. However, traditional middleware is limited in its ability to support adaptation. To address all the three problems, adaptive middleware has evolved from traditional middleware. In addition to the object-oriented programming paradigm, adaptive middleware employs several other key technologies including computational reflection, component-based design, aspect-oriented programming, and software design patterns. This survey paper proposes a three-dimensional taxonomy that categorizes different adaptive middleware approaches. Examples of each category are described and compared in detail. Suggestions for future research are also provided.