摘要： 介绍了一种元数据的语义级扩展。该扩展基于场景信息中的行为语义，描述了构件化分布式系统内相互协作的时序约束。基于改进的场景模型所制定的场景元数据规范，使用XML Schema 来描述，具有扩展性好、易于维护的特点。实验结果表明，应用场景元数据进行运行时，时序约束失配检测可以减少因非法动作所导致的资源浪费和潜在危险，从而有效提高了构件化分布式系统的协作安全。

关键词: 构件化分布式系统；行为时序约束；可靠性

Abstract: This paper proposes a metadata extension that uses the scenario information as the semantic aspect, describing the expected interaction sequences. This XML-based extension is extensible and user-friendly. With such constraints, resource waste and further damages can be avoided by preventing the illegal interactions at runtime. A prototype has been developed to illustrate the applicability of this extension. The experiments demonstrate that the prototype introduces an average overhead ratio of 6.4% in the inter-process interactions and only 0.27% in the remote interactions. The approach presented in this paper is suitable for the component-based distributed systems and affords more guarantee of reliability

Key words: Component-based distributed system; Behavior sequence constraint; Reliability