形式化语言MSC消息机制的扩展

Extending of the message mechanism for formal language MSC

为了使消息顺序图(messagesequencecharts,MSC)能更好地满足在通信领域应用的需要,在现有MSC标准的基础上,参考了其他常用的顺序图,并采用面向对象的思想,对MSC的消息机制进行扩展.MSC是用于描述系统间消息传递的一种有效的形式化语言,但现在的MSC存在着数据表达能力不强,消息顺序机制不够灵活等问题.因此,在对消息的扩展中,将消息作为一种对象进行研究,增加了消息本身的信息量.在此基础上对消息的顺序机制进行扩展,通过引入一些新的概念、符号,介绍了如何表达消息之间的相互关系和消息的运算等.扩展后的MSC能更加直观、清楚、完整地描述消息的轨迹和系统的静态与动态特性.

This paper describes the main ideas of an extension of Message Sequence Charts (MSC) to improve the ability of MSC to specify some applications (especially in the telecommunication field) more clearly and accurately. The proposed extension of MSC in this paper is focused on the message syntax and the message ordering mechanism. After a brief overview of MSC, some problems are pointed out and the principles of the extension are listed. Then, using the Object-Orientation, the message and the message ordering mechanism are regarded as object and a method separately. Some new characteristics, such as the message type, the relationship between messages, are added into the old syntax of the message and new symbols are used to express these concepts. Finally, the ordering mechanism of the MSC is extended and combined with the new message syntax, which can be used to specify some applications more effectively and clearly.