一个面向服务的支持动态演化的软件模型

为了使面向服务的架构更适应动态演化的需求，提出了基于体系结构空间、支持动态演化的软件模型SASM．SASM是使用反射技术，通过具有因果相联的基层和元层来构造．基层由可运行的服务形成，元层是一个具备树形层次、层间存在求精关系的体系结构空间．该空间反映了需求的层次性，提供给用户不同抽象级别的视图和管理手段．通过对体系结构空间的观察，可获知系统的结构和行为信息．通过对体系结构空间的在线调整可实现对基层的修改进而实现系统的非预设动态演化，而空间中不同层次之间的求精关系保证了应用的完整性和演化的一致性．

A Service-Oriented Software Model Supporting Dynamic Evolution

In order to adapt to the opening environment of Internet and the variable requirements of users, software systems should be able to adjust themselves dynamically. Dynamic evolution is required to facilitate service-oriented application system. So this paper proposes an architectural space based, dynamic evolution oriented software application model, SASM ( Software Architecture Space based Model), which is constructed by reflection technology. Its meta-level RSAS is an architecture space with tree-like layers, between which there exist refinement relations, and its base-level is composed of physical components. The meta-level and base-level are associated in the form of cause and effect. Within RSAS, different layers of architecture provide views and management means at different abstraction levels to the users, which meet the variable requirement of various roles from management layer to operation layer. Through the observation of RSAS the information of structure and behavior of application system is acquired. The on-line adjustment for RSAS can modify base-level so as to evolve application system.