在中间件中支持用户自定义连接子

Supporting User-Defined Connector in Middleware

连接子是软件体系结构设计阶段的重要概念,但在运行阶段却缺少显式的支持.描述了在J2EE应用服务器PKUAS中显式支持用户自定义连接子的机制.PKUAS连接子模型借鉴Aspect的思想,连接子由若干Advice组成,Advice对各种交互约束进行建模,Advice在运行时刻被动态调用.连接子在部署时刻由PKUAS动态生成并发布到名字服务中,由客户端在运行时刻下载到本地加载,负责构件交互.运行时刻的连接子可以和设计阶段的连接子相对应,从而保持概念的连贯性和一致性,体现了良好的关注点分离原则.

Connector is an important concept in software architecture design, but it doesn＇t get explicit support from runtime. This paper describes the work on supporting user-defined connector in J2EE application server PKUAS. The PKUAS connector model takes advantage of the Aspect technology. A construct named Advice is used to model crosscutting concerns related to interaction behaviours. These advices are organized into connector and are invoked dynamically at runtime. At deployment time, PKUAS will generate a client-side connector object and publish it to a naming service. Application clients download the connector object to a local machine to manage the component interactions. Runtime connectors correspond well to those in the design time, thus narrowing the concept gap greatly. This flexible and modular approach effectively facilitates the separation of concerns.