【作者】 黄玉坤； 陈榕； 王芳；

【Author】 Huang Yukun1+, Chen Rong1, Wang Fang1 1 (System Software Engineering Center of Tongji University, Shanghai 200092, China)

【机构】 同济大学基础软件工程中心；

【摘要】 本文通过结合普适计算理论,讨论基于CAR构件技术及Elastos平台来构建普适计算环境的可行性和方法。当今,移动通信设备和各种智能电子设备越来越成为普适计算的重要组成部分。针对常在线消费电子网络环境,上海科泰世纪科技有限公司实现了CAR(Component Assembly Runtime)构件技术以及为其提供运行时支撑的Elastos网络构件运行平台。CAR构件技术是个内涵丰富的技术体系,它包括元数据计算、Elastos URL自动软件构件寻址、按需加载按需计算、XmlGlue编程、面向侧面编程、泛类编程等内容。它为普适计算的人机交互界面的设计、动态换肤技术、软件构件的动态下载升级和按需加载、系统运行组件的自动配置和自适应、上下文环境敏感性编程等需求提供技术支持。与传统的面向过程及面向对象编程模型相比,CAR构件技术强调了目标代码级的软件构件制造及发布;强调了使用URL对软件构件进行编址;强调利用XML+脚本的形式进行软件构件装配。借助于URL及HTTP等标准因特网基础设施与Elastos网络构件运行平台,可以实现软件构件的动态下载和升级,为人们动态提供最合适的软件计算环境。更多还原

【Abstract】 Combined with the theory of pervasive computing,the potential possibility of building a new type of pervasive computing envionment based on CAR(Component Assembly Runtime) technology and Elastos platform is dicussed in this paper. Nowadays,the mobile communication equipment and intelligent electronic equipment have become a more and more important part of pervasive computing. Elastos platform ,which based on CAR component technology, is designed and implemented by Shanghai Koretide Co. It is an embedded operating system to facilitate future consumer electronics, such as 3G Mobile Phones and HDTV’s, which are connected to the network most of the time.CAR components run on Elastos. CAR is a meaningful technology and theory system, including computing of metadata, auto locating of software component through URL, loading module and computing on demand, and programming paradigm of XmlGlue, AOP and Generic. CAR and Elastos platform offer technic support for pervasive computing, such as man-machine interaction interface, dynamically changing UI skin, Updating software components on demand, and so on. Compared with traditional Process Oriented Programming and Object Oriented Programming, there are some special features of CAR Programming: (1) Based on binary object code with class-information; (2) Assigning a URL address to each CAR component; (3) Class and method names of a CAR component become XML tags upon loading. With the help of ubiquitous Internet infrastructures and Elastos platform, dynamic download and update of Software Component are implemented, and the most suitable software computing environment is provided dynamically. Based on Generic Programming of Elastos, the objects, different of conerte class inheritant from the same Generic class, are instanced by overloading New function of Generic class. So we make it possible to realize the automatic configuration and adaptive component of the software system on runtime. For example, we can instant a network connector component by a generic class without care of which concrete connector of special protocol should be created. Because the new() function of the generic class will help you to get a right network connector component according to the state of the network. Based on Aspect Oriented Programmin of CAR, we implement context-aware computing through the computing of the metadata among the Aspect components , Context components, and Entity components.Aspect Oriented Programming of CAR present some special conception: (1) Entity component, which denote a entity object who can enter or leave different contexts; (2) Context, which is a abstract conception, is a collection of some related features we named as aspect; (3)Aspects, are some special features related with a context who have infection on the entity objects who entered it. When entity object entered a context , it will aggregated with all aspect in the context. And these aspect endow some new functions to the entity object. Wh更多还原