XML中的主动规则及其可终止性分析  

Active Rules and thier Termination in XML

作　　者：李晖[1] 孔兰菊[1] 洪晓光[1] 

机构地区：[1]山东大学计算机科学与技术学院,济南250100

出　　处：《计算机科学》2004年第9期93-95,共3页Computer Science

摘　　要：主动XML系统一般采用触发器,即"事件-冬件-动作"(ECA)规则来提供主动行为。本文提出了一种新的事件监测机制,在XML系统中引入‘主动节点’,即把规则也融入节点,各节点上的ECA规则只需在节点修改时被激活并进行检查,提高了动作的执行效率,增强了系统的实时性。本文结合规则实例给出了分析规则终止性的静态判定算法,引入触发图、活化图、修改后的触发图、触发环等概念,对触发图中的简单触发环进行转换,产生一个对应于触发环的循环语句,对触发环中每一个被修改的节点产生一个递归等式。展开递归等式检验它的可满足性可以用来分析规则集的可终止性。这一算法提高了可终止性判定的精确性,降低了复杂度。XML is rapidly emerging as the most widely adopted technology for information representation and exchange in the applications. By means of active rules,it becomes possible to generate or manipulate the content of an XML document as a reaction to changes that occur to XML information. In this paper,we introduce a new rule execute model in active class in the XML environment. We discuss the rule analysis theory and propose an analysis approach,which can decide whether the rule sets can be terminated or not. Node ,which forms the XML document ,is instance of the active class. When the node is modified and the rule's condition is satisfied,the rule's action will be acted. There is no event listener with which applications often become inefficient and unmanageable when the number of triggers becomes large. In this paper we derive a recursion equation for each node that is modified, in the cycle. Unfolding of the recursion equations and testing for the satisfiability are used to analyze the termination of the rule. Apart from the improved precision it can achieve ,we are able to make statements about conditional termination properties of an ECA rule set.

关 键 词：XML 递归 主动规则 分析规则 触发 结合规则 可满足性 终止 激活 监测机制 

分 类 号：TP311[自动化与计算机技术—计算机软件与理论] TP393[自动化与计算机技术—计算机科学与技术]