基于扩展ECA的分布式工作流研究及其应用
摘要
工作流技术是近年来随着Internet和Intranet的日益普及而迅速发展的技术研究领域之一。工作流管理系统是业务流程管理的重要基础,主要目标是通过调用有关信息资源与人力资源来协调业务流程中的各个环节,是指按照一定的顺序依次进行,从而实现业务流程的自动化。
随着企业的全球化和网络技术的迅速发展,现代企业信息环境的分布、异构和自治等特性越来越明显。在这种客观背景下,基于广域网技术、分布式计算技术,支持企业之间及企业内部跨地域的分布式工作流系统成为工作流技术发展的必然趋势和当今研究的热点。然而大部分分布式工作流管理系统都采用集中式管理结构,即在分布式工作流执行中有一个主控工作流引擎来负责从属工作流引擎的控制与协调,这种结构在兼容性、可扩展性、可靠性等方面都存在缺点。在分布式工作流管理系统中还有很多关于时间方面的问题没有解决,限制了其描述能力。
本文是在分析现有分布式工作流系统的基础上,提出一种基于扩展ECA规则和事件驱动机制的分布式工作流系统实现方案,它通过工作流引擎上的扩展ECA规则来完成工作流中的任务执行。首先将ECA规则在时间上进行扩展,解决了ECA规则在描述与时间相关的复杂过程时能力不足的问题,并将事件重写为事件发生时刻,使事件表达式具有更强的表达能力,使之有丰富的可用性。利用UML活动图进行建模,并增加空活动和带触发条件的转移这两种建模元素,丰富了UML活动图的语义,提高了工作流模型描述能力。在最后给出集装箱物流管理系统中的应用示例,并结合具体业务流程对实现过程作了简要描述。
With the increasing prevalence of Internet and Intranet, workflow technology is one of the fields developing most rapidly. Workflow system is the most important foundation of business process. The main target of workflow system is the automation of procedures where documents, information or tasks are passed between participants according to a predefined set of rules to achieve an overall business goal.
Distribution, Heterogeneity and autonomy of modern enterprise’s information become more and more remarkable with the fast development of IT technology and enterprise’s globalization. On this objective background, the distributed workflow system, that supports distributed computing and collaboration among departments or enterprises, becomes the focus and future trend of workflow technology study. But most of the distributed workflow management systems have made use of centered management system, namely in the distributed workflow execution, there is only one primary workflow engine in charge of controlling and cooperating the subordinate workflow engines. As a result of some time problems within the workflow system not settled, the area of its description is limited.
So, under the analysis of former distributed workflow technology, we bring forward a distributed workflow system based on Extended-ECA rule and event-driven mechanism, and it completes tasks in workflow by Extended-ECA rules of the workflow engines. First of all, extended ECA rule which extends in time, resolves the problems of ECA rule’s deficient in describing complex process related to time, and rewriting the event into the occurrence time of the event makes the event expression have more expression semantics; define the workflow process by UML activity diagram, and add model elements to activity diagram, enlarge the describing ability of workflow model. This technology is applied in Container Logistics Information System, and the implementation of a process instance is also described.
随着企业的全球化和网络技术的迅速发展,现代企业信息环境的分布、异构和自治等特性越来越明显。在这种客观背景下,基于广域网技术、分布式计算技术,支持企业之间及企业内部跨地域的分布式工作流系统成为工作流技术发展的必然趋势和当今研究的热点。然而大部分分布式工作流管理系统都采用集中式管理结构,即在分布式工作流执行中有一个主控工作流引擎来负责从属工作流引擎的控制与协调,这种结构在兼容性、可扩展性、可靠性等方面都存在缺点。在分布式工作流管理系统中还有很多关于时间方面的问题没有解决,限制了其描述能力。
本文是在分析现有分布式工作流系统的基础上,提出一种基于扩展ECA规则和事件驱动机制的分布式工作流系统实现方案,它通过工作流引擎上的扩展ECA规则来完成工作流中的任务执行。首先将ECA规则在时间上进行扩展,解决了ECA规则在描述与时间相关的复杂过程时能力不足的问题,并将事件重写为事件发生时刻,使事件表达式具有更强的表达能力,使之有丰富的可用性。利用UML活动图进行建模,并增加空活动和带触发条件的转移这两种建模元素,丰富了UML活动图的语义,提高了工作流模型描述能力。在最后给出集装箱物流管理系统中的应用示例,并结合具体业务流程对实现过程作了简要描述。
With the increasing prevalence of Internet and Intranet, workflow technology is one of the fields developing most rapidly. Workflow system is the most important foundation of business process. The main target of workflow system is the automation of procedures where documents, information or tasks are passed between participants according to a predefined set of rules to achieve an overall business goal.
Distribution, Heterogeneity and autonomy of modern enterprise’s information become more and more remarkable with the fast development of IT technology and enterprise’s globalization. On this objective background, the distributed workflow system, that supports distributed computing and collaboration among departments or enterprises, becomes the focus and future trend of workflow technology study. But most of the distributed workflow management systems have made use of centered management system, namely in the distributed workflow execution, there is only one primary workflow engine in charge of controlling and cooperating the subordinate workflow engines. As a result of some time problems within the workflow system not settled, the area of its description is limited.
So, under the analysis of former distributed workflow technology, we bring forward a distributed workflow system based on Extended-ECA rule and event-driven mechanism, and it completes tasks in workflow by Extended-ECA rules of the workflow engines. First of all, extended ECA rule which extends in time, resolves the problems of ECA rule’s deficient in describing complex process related to time, and rewriting the event into the occurrence time of the event makes the event expression have more expression semantics; define the workflow process by UML activity diagram, and add model elements to activity diagram, enlarge the describing ability of workflow model. This technology is applied in Container Logistics Information System, and the implementation of a process instance is also described.
引文
[1]罗海滨,范玉顺,吴澄.工作流技术综述.软件学报,2000,11(7)
[2]范玉顺等.工作流管理技术基础.清华大学出版社.2001
[3] G.Alonso,D.Agrawal,A.El Abbadi,C.Mohan Fuctionality and Limitations of Current Workflow Management Systems,IEEE-Expert,1997
[4] Workflow Management Coalition.Terminology&Glossary.WFMC-TC-1011,1999.
[5] C.Monhan.Recent Trends in Workflow Management Products,Standars,and Reserch.1997,http://www.almaden.ibm.com/cs/exotica/wfnato97.ps
[6] G.Alonso,D.Agrawal,A.EL Abbadi,C.Mohan Functionality and limitations of current workflow management systems,1997 http://www.alnmden.ibm.com/cs/exotica/wfmsys.ps
[7] M Rusinkiewicz,A Sheth.Specification and Execution of Transactional Workflows.Modern Database Systems.ACM press/Addison-Wesley Publishing Co.1995.592-620.
[8] G.Alonso,C.Hagen,H.-J.Schek,M.Tresch Distributed Processing over Stand-alone Systems and Applications,In Proc. 23rd VLDB,Athens,Greece,August 1997
[9] Xie Yongyi,ZhangWeishi Component-Based Workflow Architecture of a Distributed Software Process Management System,Proceedings of the Third International Conference on Quality Software,2003
[10]万建成,卢雷,软件体系结构的原理、组成与应用,科学技术出版社,2002.
[11]刘大欣.基于J2EE的分布式工作流管理系统研究.南京航空航天大学硕士学位论文.2004.
[12] IBM Almaden Research Center. Exotica/FMQM:A persistent message-based architecture for distributed workflow management[C].In: Proc IFIP WG8.1 Working Conference on Information Systems for ecentralized Organization,1995
[13] A Geppert, D Tombros. Event-based distributed workflow execution with EVE[R]. SWORDIES Report, 1998
[14]范玉顺,吴澄工作流管理技术研究与产品现状及发展趋势[J],计算机集成制造系统CIMS,2000,6(1):3-8
[15] James Bailey,Alexandra Poulovassilis,Peter Newson.A Dynamic Approach to Termination Analysis for Active Database Rules.1996.
[16] Widom J.,Ceri S.. Active Databse Systems[M].Morgan-Kaufmann,1995.
[17] Terada T.,Tsukamoto M.,Nishio M.. Dynamic Construction Mechanism of a Trigger Graph on Active Databases in Mobile Computing Environments,14th International Workshop on Database and Expert Systems Applications(DEXA'03),2003.
[18]胡锦敏,张申生,余新颖.基于ECA规则和活动分解的工作流模型.软件学报,2002,第13卷,第4期.
[19]姜跃平等.ECA规则的模型和行为特定理论[J].软件学报,1997,8(3):190-196.
[20]刘云生:现代数据库技术(第一版),国防工业出版社,2001.
[21]李庆忠:主动面向对象数据库的主动机制研究及应用,中科院博士论文,2000.
[22]何新贵:事件代数与主动知识库系统,软件学报,1994.9.
[23] Marlon Dumas,Arthur H M ter Hofstede.UML Activity Diagrams as a workflow Specification Language,http://citeseer.nj.nec.com/455908.html
[24] UML翼振燕.UML系统分析设计与应用案例.第1版,北京:人民邮电出版社.2003
[25]孙明等.支持复合事件的主动规则的可终止性分析.计算机研究与发展.1998,Vol.35,No.5
[26] A Geppert, D Tombros. Logging and post-mortem analysis of workflow executions based on event histories[C].In: Proc 3rd Intl Workshop on Rules in Database Systems, Skoevde, Sweden, 1997-06
[27] A Geppert, D Tombros. Logging and post-mortem analysis of workflow executions based on event historier[C]. In: Proc 3rd Intl Workshop on Rules in Databse Systems, Skoevde, Sweden, 1997-06
[28] S.Ceri, J.Widom Deriving production rules for constraint maintenance, Proc.Intel Conf. Very Large Data Bases, 1990
[29] Sharma Chakravarthy, Roger Le, Rajesh Dasari, ECA Rule Processing in Distributed and Heterogeneous Environments Proceeding of the International Symposium on Distributed Objects and Applications, 1999
[30] Robert M. Event-Oriented Dynamic Adaptation of Workflow: Model, Architecture and Implementation, University of Leipzig, 2003
[31]徐正权等.基于ECA规则的工作流过程建模.计算机工程与科学.2006,Vol.28,No.5
[32]张颖等.基于活动分解和ECA规则的软件过程建模.计算机工程与设计.2005,Vol.26,No.3
[2]范玉顺等.工作流管理技术基础.清华大学出版社.2001
[3] G.Alonso,D.Agrawal,A.El Abbadi,C.Mohan Fuctionality and Limitations of Current Workflow Management Systems,IEEE-Expert,1997
[4] Workflow Management Coalition.Terminology&Glossary.WFMC-TC-1011,1999.
[5] C.Monhan.Recent Trends in Workflow Management Products,Standars,and Reserch.1997,http://www.almaden.ibm.com/cs/exotica/wfnato97.ps
[6] G.Alonso,D.Agrawal,A.EL Abbadi,C.Mohan Functionality and limitations of current workflow management systems,1997 http://www.alnmden.ibm.com/cs/exotica/wfmsys.ps
[7] M Rusinkiewicz,A Sheth.Specification and Execution of Transactional Workflows.Modern Database Systems.ACM press/Addison-Wesley Publishing Co.1995.592-620.
[8] G.Alonso,C.Hagen,H.-J.Schek,M.Tresch Distributed Processing over Stand-alone Systems and Applications,In Proc. 23rd VLDB,Athens,Greece,August 1997
[9] Xie Yongyi,ZhangWeishi Component-Based Workflow Architecture of a Distributed Software Process Management System,Proceedings of the Third International Conference on Quality Software,2003
[10]万建成,卢雷,软件体系结构的原理、组成与应用,科学技术出版社,2002.
[11]刘大欣.基于J2EE的分布式工作流管理系统研究.南京航空航天大学硕士学位论文.2004.
[12] IBM Almaden Research Center. Exotica/FMQM:A persistent message-based architecture for distributed workflow management[C].In: Proc IFIP WG8.1 Working Conference on Information Systems for ecentralized Organization,1995
[13] A Geppert, D Tombros. Event-based distributed workflow execution with EVE[R]. SWORDIES Report, 1998
[14]范玉顺,吴澄工作流管理技术研究与产品现状及发展趋势[J],计算机集成制造系统CIMS,2000,6(1):3-8
[15] James Bailey,Alexandra Poulovassilis,Peter Newson.A Dynamic Approach to Termination Analysis for Active Database Rules.1996.
[16] Widom J.,Ceri S.. Active Databse Systems[M].Morgan-Kaufmann,1995.
[17] Terada T.,Tsukamoto M.,Nishio M.. Dynamic Construction Mechanism of a Trigger Graph on Active Databases in Mobile Computing Environments,14th International Workshop on Database and Expert Systems Applications(DEXA'03),2003.
[18]胡锦敏,张申生,余新颖.基于ECA规则和活动分解的工作流模型.软件学报,2002,第13卷,第4期.
[19]姜跃平等.ECA规则的模型和行为特定理论[J].软件学报,1997,8(3):190-196.
[20]刘云生:现代数据库技术(第一版),国防工业出版社,2001.
[21]李庆忠:主动面向对象数据库的主动机制研究及应用,中科院博士论文,2000.
[22]何新贵:事件代数与主动知识库系统,软件学报,1994.9.
[23] Marlon Dumas,Arthur H M ter Hofstede.UML Activity Diagrams as a workflow Specification Language,http://citeseer.nj.nec.com/455908.html
[24] UML翼振燕.UML系统分析设计与应用案例.第1版,北京:人民邮电出版社.2003
[25]孙明等.支持复合事件的主动规则的可终止性分析.计算机研究与发展.1998,Vol.35,No.5
[26] A Geppert, D Tombros. Logging and post-mortem analysis of workflow executions based on event histories[C].In: Proc 3rd Intl Workshop on Rules in Database Systems, Skoevde, Sweden, 1997-06
[27] A Geppert, D Tombros. Logging and post-mortem analysis of workflow executions based on event historier[C]. In: Proc 3rd Intl Workshop on Rules in Databse Systems, Skoevde, Sweden, 1997-06
[28] S.Ceri, J.Widom Deriving production rules for constraint maintenance, Proc.Intel Conf. Very Large Data Bases, 1990
[29] Sharma Chakravarthy, Roger Le, Rajesh Dasari, ECA Rule Processing in Distributed and Heterogeneous Environments Proceeding of the International Symposium on Distributed Objects and Applications, 1999
[30] Robert M. Event-Oriented Dynamic Adaptation of Workflow: Model, Architecture and Implementation, University of Leipzig, 2003
[31]徐正权等.基于ECA规则的工作流过程建模.计算机工程与科学.2006,Vol.28,No.5
[32]张颖等.基于活动分解和ECA规则的软件过程建模.计算机工程与设计.2005,Vol.26,No.3