反射中间件的研究与进展

Research and Advance of Reflective Middleware

反射中间件是当前中间件技术研究中值得注意的一个新方向.它克服了传统中间件“黑箱”结构的缺陷,具有系统结构行为有序开放、可重配置等特点,能支持针对不同应用类型进行定制,可较好地适应动态变化的分布式环境和应用需求,已在移动计算、多媒体应用等多个领域展现出较好的应用前景.该文在介绍反射计算与反射系统基本知识的基础上,首先分析归纳了反射中间件的核心概念和基本原理,给出一个反射中间件的一般结构.在此基础上提出一个反射中间件分类与比较框架,涵盖了反射类型、反射时间、反射范围、实现机制等方面的内容,而后依据此框架对目前几种具有代表性的反射中间件系统作综述和比较.最后对该领域值得进一步研究的问题进行了分析和讨论.

Reflective middleware is a noteworthy new direction of middleware research. It elimi- nates the deficiency of traditional object-oriented middleware systems by opening their “black- box”structure and providing inspection and adaptation capabilities for developers with computa- tional reflection techniques. Reflective middleware supports the customization for different application domains and the adaptation of distributed applications to dynamically evolving environments and user requirements. Its strength has already been shown in the areas such as mobile computing, multimedia applications, etc. In this paper, after a brief introduction on computational reflection and reflective system, the kernel concepts and principles of reflective middleware are firstly introduced and a general reflective middleware structure is presented. Then authors propose a classification and comparison framework which characterizes reflective middleware systems from the aspects of reflection styles, reflection time, reflection scope and implementation mechanisms. Based on this framework, several representative reflective middleware systems are overviewed and compared. And finally, the future problems in this area are discussed.