Coordinating components in middleware systems

Abstract

Configuration and coordination are central issues in the design and implementation of middleware systems and are one of the reasons why building such systems is more complex than constructing stand-alone sequential programs. Through configuration, the structure of the system is established—which elements it contains, where they are located and how they are interconnected. Coordination is concerned with the interaction of the various components—when an interaction takes place, which parties are involved, what protocols are followed. Its purpose is to coordinate the behaviour of the various components to meet the overall system specification. The open and adaptive nature of middleware systems makes the task of configuration and coordination particularly challenging. We propose a model that can operate in such an environment and enables the dynamic integration and coordination of components by observing and coercing their behaviour through the interception of the messages exchanged between them. Copyright © 2003 John Wiley & Sons, Ltd.