基于P2P的工作流管理系统的设计与实现
摘要
传统的工作流系统大多以工作流管理联盟的工作流模型为基础,采用基于客户端/服务器的模式,将资源集中存储在服务器上,这种模式下虽然有易于管理和数据一致性等优点,而且已经被广泛的应用于生产制造、办公自动化等领域,但是其中心化的服务器不仅影响系统性能而且容易导致单点故障,而且频繁的访问服务器会给服务器带来很大负担,从而影响工作流程的顺利执行。
随着工作流的发展,基于C/S模式的工作流系统逐渐不适应当今形势的发展。现在对工作流系统的分布式、自治性、容错性和灵活性要求越来越高。在通常情况下,企业的应用一般都运行在分布式环境上,那么相应的工作流机也应该采用运行在分布式环境下的分布式结构。对等网络的出现正好满足了这一需求,它是分布式系统和计算机网络相结合的产物。对等网络的出现使得网络工作模式从集中式走向分布式,网络应用的核心从服务器走向每一个网络节点。由于P2P网络自由、平等、互联的特点,使得基于P2P的工作流成为一个热门方向。
本文通过引入P2P的概念,在P2P信息技术和消息传递的基础上,设计一个基于分片因子的文件传输算法,将流程需要处理的文件进行分片处理,这样既避免了原来基于客户端/服务器模式单点失效的问题,又充分利用了各个对等点资源,使得工作流执行所需的较大附件能够快速的发送到参与者对应的对等点上。通过自己定义表单以及合理的组织机构、工作流程,实现发起流程、流程处理、信息反馈等功能。本文基于JXTA平台,并采用查找后继的方法驱动工作流的运行。最后,在充分研究的基础上实现了在JXTA平台基础之上的工作流管理系统,该管理系统提供更快捷,可靠,灵活和适应性的服务。
Most traditional workflow systems are based on workflow models proposed by WFMC and structured as C/S. As all the resources are saved on servers, not only data consistency is guaranteed, but can be widely used for production and automation, however, center-based server not only has an impact on system efficiency, but also leads to one point malfunction. The server slowed down due to frequent visit and the process of workflow can not be executed smoothly.
As the development of workflow, the workflow based on centralized C/S architecture can not adapt the current situation. Nowadays, the distribution、autonomy、tolerance and flexibility of workflow is increasingly demanding. Generally speaking, the application of enterprise developed in distributed environments, accordingly, workflow system should also be developed with a distributed structure. P2P just meets the requirement and is the combination of distributed system and computer network. P2P enabled network model to transform from centered model to distributed model. The core use of network turned to every peer instead of servers. Due to the flexibility、equality、interconnection of P2P, The workflow based on P2P became a great direction.
This paper presents the concept of P2P and designs a file transformation algorithm based on P2P information technology and message delivery. All the files involved in the flow are handled in several sections. In this way, we easily handle the risk of single-source bottleneck and make good use of resources of peers that enable us to send big accessory required by workflow to the due participant accordingly. The paper develops functions of initiating flow, handling flow and information feedback by defining forms and proper organizations. The running of workflow is driven by searching successor based on the platform of JXTA. Finally, the paper implemented the workflow management system based on JXTA and the system provided more efficient, reliable, flexible and adaptive service.
随着工作流的发展,基于C/S模式的工作流系统逐渐不适应当今形势的发展。现在对工作流系统的分布式、自治性、容错性和灵活性要求越来越高。在通常情况下,企业的应用一般都运行在分布式环境上,那么相应的工作流机也应该采用运行在分布式环境下的分布式结构。对等网络的出现正好满足了这一需求,它是分布式系统和计算机网络相结合的产物。对等网络的出现使得网络工作模式从集中式走向分布式,网络应用的核心从服务器走向每一个网络节点。由于P2P网络自由、平等、互联的特点,使得基于P2P的工作流成为一个热门方向。
本文通过引入P2P的概念,在P2P信息技术和消息传递的基础上,设计一个基于分片因子的文件传输算法,将流程需要处理的文件进行分片处理,这样既避免了原来基于客户端/服务器模式单点失效的问题,又充分利用了各个对等点资源,使得工作流执行所需的较大附件能够快速的发送到参与者对应的对等点上。通过自己定义表单以及合理的组织机构、工作流程,实现发起流程、流程处理、信息反馈等功能。本文基于JXTA平台,并采用查找后继的方法驱动工作流的运行。最后,在充分研究的基础上实现了在JXTA平台基础之上的工作流管理系统,该管理系统提供更快捷,可靠,灵活和适应性的服务。
Most traditional workflow systems are based on workflow models proposed by WFMC and structured as C/S. As all the resources are saved on servers, not only data consistency is guaranteed, but can be widely used for production and automation, however, center-based server not only has an impact on system efficiency, but also leads to one point malfunction. The server slowed down due to frequent visit and the process of workflow can not be executed smoothly.
As the development of workflow, the workflow based on centralized C/S architecture can not adapt the current situation. Nowadays, the distribution、autonomy、tolerance and flexibility of workflow is increasingly demanding. Generally speaking, the application of enterprise developed in distributed environments, accordingly, workflow system should also be developed with a distributed structure. P2P just meets the requirement and is the combination of distributed system and computer network. P2P enabled network model to transform from centered model to distributed model. The core use of network turned to every peer instead of servers. Due to the flexibility、equality、interconnection of P2P, The workflow based on P2P became a great direction.
This paper presents the concept of P2P and designs a file transformation algorithm based on P2P information technology and message delivery. All the files involved in the flow are handled in several sections. In this way, we easily handle the risk of single-source bottleneck and make good use of resources of peers that enable us to send big accessory required by workflow to the due participant accordingly. The paper develops functions of initiating flow, handling flow and information feedback by defining forms and proper organizations. The running of workflow is driven by searching successor based on the platform of JXTA. Finally, the paper implemented the workflow management system based on JXTA and the system provided more efficient, reliable, flexible and adaptive service.
引文
[1]NEIL D,HECTOR G M,BEVERLY Y.Open problems in data-sharing peer-to-peer systems [C].Proceedings of the 9th International Conference on Database Theroy,Springer,2003.
[2]FOEST G,PAFFRATH R.Peer-to-Peer(P2P)and beyond[R].DFN Mitteilungen,2002,3(58).
[3]NOLL J.A peer-to-peer architecture for workflow in virtual Enterprises[C].Proceedings of the Fifth International Conference on Quality Software.Santa Clara,CA,2005:365-372.
[4]刘康,陈前斌.基丁非结构化P2P的工作流管理系统[J].软件学报,2007,29(8):1980-1986.
[5]MOHAN C,ALONSO G,GUNTHOR R,et al.Exotica:a research perspective on workflow management systems[C].IBM Almaden Research Center,USA,2000:18-24.
[6]STEINMETZ R,WEHRLE K.Peer-to-peer systems and applications[M].Berlin:Springer,2005:20-29.
[7]YAN J,YANG Y,KOWALCZYK R,NGUYEN X T.A service workflow management framework based on peer-to-peer and agent technologies[C].Proceedings of the Fifth International Conference on Quality Software.Hawthorn,2005:373-380.
[8]许斌.JXTA-Java P2P网络编程技术[M].北京:清华大学出版社,2003:35-75.
[9]RICHARD S.Napster:a walking copyright infringement[C].IEEE Micro,2000,20(6):4-5.
[10]MATTHEW C,MIGUEL C,EDMUND B N,et al.Virtual ring routing:network routing inspired by DHTs [C].ACM SIGCOMM Computer Communication Review,2006:351-362.
[11]JIN F H,HONG L Y,HAI T D.PeerWindow:an efficient,heterogeneous,and autonomic node collection protocol[C].Proceedings of the 2005 International Conference on Parallel,Washington D.C,2005:511-520.
[12]MIGUEL C,MANUEL C,ANTONY R.Debunking some myths about structured and unstructured overlays [C].Proceedings of 2nd Symposium on Networked Systems Design and Implementation,Boston,2005:85-98.
[13]YANJ,YANG Y,RAIKUNDALIA G K.A data storage mechanism for peer-to-peer based decentralised workflow systems[J].Proc of 15th Int Conf on Software Engineering and Knowledge Engineering,San Francisco,2003:354-358.
[14]ALLEN R.Workflow:An introduction[J].Information Systems,2001,103(2):32-39.
[15]SMITH H.Business process management-the third wave:business process modelling language(bpml)and its pi-calculus foundations[J].Information and Software Technology,2003,45(15):1065-1069.
[16]WILVAN D A,KEES V H.工作流管理:模型、方法和系统[M].北京清华大学出版社,2004:45-60
[17]LAWRENCE P,Editor.Workflow Handbook 1997,Workflow Management Coalition[M].John Wiley and Sons,New York,1997.
[18]STOICAI,MORRIS R,KARGER D.Chord:a scalable peer-to-peer lookup service for internet Applications[C].ACM Special Interest Group on Data Communication,USA,2001:149-160.
[19]ROWSTRON A,DRUSCHRL P.Pastry:Scalable,Distributed Object Location and Routing for
Large-Scale Peer-to-Peer Systems[C].IFIP/ACM International Conference on Distributed
Systems Platforms,Heidelberg,2001,329-350.
[20]OBERMAISSER R.Reuse of CAN-based legacy applications in time-triggered architectrures [C].IEEE of Industrial Informatics,2006,2(4):255-268.
[21]ZBAO B Y,HUANG L,STRIBLING J.rapestry:a resilient global-scale overlay for service deployment[C].IEEE Journal on Selected Areas in Communications,2004,22(1):41-53.
[22]FRANCA D,From pastry to crossroad:cross-layer ring overlay for ad hoc networks[C].3rd IEEE International Conference on Pervasive Computing and Communications Workshops (PERCOMW'05),2005:60-64.
[23]KARL A,ANWITAMAN D,MANFRED H.Multifaceted simultaneous load balancing in DHT-based P2P systems:A new game with old balls and bins[C].Self-star Properties in Complex Information Systems,Springer Berlin,2005:373-391.
[24]YATIN C,SYLVIA R,LEE B.Making gnutella-like P2P systems scalable[C].ACM SIGCOMM 2003Conference on Applications,Technologies,Architectures,and Protocols for Computer Communication,Karlsruhe of Germany,2003:408-417.
[25]黄道颖,张安琳,黄建华,等.P2P网络Gnutella 0.6模型研究[J].计算机应用与软件,2008,25(6):208-210.
[26]侯孟书,卢显良,周旭等.非结构化P2P系统的路由算法[J].电子科技大学学报,2005,1(30):105-106.
[27]TOBIAS H,KENJI L,RASTIN P,et al.Information diffuseion in eDonkey filesharing networks [C].ATNAC,Sydney,2004.
[28]LIANG J,RAKESH K,KEITH W R.The kazaa overlay:a measurement study[J].Computer Networks Journal,2005,50(6):842-858.
[29]WANG J Z,MA Z D,GREGORY M H.A distributed mechanical system simulation platform based on a "Gluing Algorithm"[C].Journal of Computing and Information Science in Engineering,2005,5(1):71-74.
[30]OAKS S,TRAVESRSAT B,GONG L.JXTA技术手册[M].北京:清华大学出版社,2004.
[31]PANTI M,PENSERINI L.A P2P approach to land warriors coordination[R].CTS'03:The 2003International Symposium on Collaborative Technologies and Systems,Orlando of Florida,2003:109-117.
[32]JEAN M S,GREGORY B,CHRISTIAN D J.P2P with JXTA-Java pipes[A].2nd International Conference on Principles and Practice of Programming in Java,Kilkenny of Ireland,2003:208-210.
[2]FOEST G,PAFFRATH R.Peer-to-Peer(P2P)and beyond[R].DFN Mitteilungen,2002,3(58).
[3]NOLL J.A peer-to-peer architecture for workflow in virtual Enterprises[C].Proceedings of the Fifth International Conference on Quality Software.Santa Clara,CA,2005:365-372.
[4]刘康,陈前斌.基丁非结构化P2P的工作流管理系统[J].软件学报,2007,29(8):1980-1986.
[5]MOHAN C,ALONSO G,GUNTHOR R,et al.Exotica:a research perspective on workflow management systems[C].IBM Almaden Research Center,USA,2000:18-24.
[6]STEINMETZ R,WEHRLE K.Peer-to-peer systems and applications[M].Berlin:Springer,2005:20-29.
[7]YAN J,YANG Y,KOWALCZYK R,NGUYEN X T.A service workflow management framework based on peer-to-peer and agent technologies[C].Proceedings of the Fifth International Conference on Quality Software.Hawthorn,2005:373-380.
[8]许斌.JXTA-Java P2P网络编程技术[M].北京:清华大学出版社,2003:35-75.
[9]RICHARD S.Napster:a walking copyright infringement[C].IEEE Micro,2000,20(6):4-5.
[10]MATTHEW C,MIGUEL C,EDMUND B N,et al.Virtual ring routing:network routing inspired by DHTs [C].ACM SIGCOMM Computer Communication Review,2006:351-362.
[11]JIN F H,HONG L Y,HAI T D.PeerWindow:an efficient,heterogeneous,and autonomic node collection protocol[C].Proceedings of the 2005 International Conference on Parallel,Washington D.C,2005:511-520.
[12]MIGUEL C,MANUEL C,ANTONY R.Debunking some myths about structured and unstructured overlays [C].Proceedings of 2nd Symposium on Networked Systems Design and Implementation,Boston,2005:85-98.
[13]YANJ,YANG Y,RAIKUNDALIA G K.A data storage mechanism for peer-to-peer based decentralised workflow systems[J].Proc of 15th Int Conf on Software Engineering and Knowledge Engineering,San Francisco,2003:354-358.
[14]ALLEN R.Workflow:An introduction[J].Information Systems,2001,103(2):32-39.
[15]SMITH H.Business process management-the third wave:business process modelling language(bpml)and its pi-calculus foundations[J].Information and Software Technology,2003,45(15):1065-1069.
[16]WILVAN D A,KEES V H.工作流管理:模型、方法和系统[M].北京清华大学出版社,2004:45-60
[17]LAWRENCE P,Editor.Workflow Handbook 1997,Workflow Management Coalition[M].John Wiley and Sons,New York,1997.
[18]STOICAI,MORRIS R,KARGER D.Chord:a scalable peer-to-peer lookup service for internet Applications[C].ACM Special Interest Group on Data Communication,USA,2001:149-160.
[19]ROWSTRON A,DRUSCHRL P.Pastry:Scalable,Distributed Object Location and Routing for
Large-Scale Peer-to-Peer Systems[C].IFIP/ACM International Conference on Distributed
Systems Platforms,Heidelberg,2001,329-350.
[20]OBERMAISSER R.Reuse of CAN-based legacy applications in time-triggered architectrures [C].IEEE of Industrial Informatics,2006,2(4):255-268.
[21]ZBAO B Y,HUANG L,STRIBLING J.rapestry:a resilient global-scale overlay for service deployment[C].IEEE Journal on Selected Areas in Communications,2004,22(1):41-53.
[22]FRANCA D,From pastry to crossroad:cross-layer ring overlay for ad hoc networks[C].3rd IEEE International Conference on Pervasive Computing and Communications Workshops (PERCOMW'05),2005:60-64.
[23]KARL A,ANWITAMAN D,MANFRED H.Multifaceted simultaneous load balancing in DHT-based P2P systems:A new game with old balls and bins[C].Self-star Properties in Complex Information Systems,Springer Berlin,2005:373-391.
[24]YATIN C,SYLVIA R,LEE B.Making gnutella-like P2P systems scalable[C].ACM SIGCOMM 2003Conference on Applications,Technologies,Architectures,and Protocols for Computer Communication,Karlsruhe of Germany,2003:408-417.
[25]黄道颖,张安琳,黄建华,等.P2P网络Gnutella 0.6模型研究[J].计算机应用与软件,2008,25(6):208-210.
[26]侯孟书,卢显良,周旭等.非结构化P2P系统的路由算法[J].电子科技大学学报,2005,1(30):105-106.
[27]TOBIAS H,KENJI L,RASTIN P,et al.Information diffuseion in eDonkey filesharing networks [C].ATNAC,Sydney,2004.
[28]LIANG J,RAKESH K,KEITH W R.The kazaa overlay:a measurement study[J].Computer Networks Journal,2005,50(6):842-858.
[29]WANG J Z,MA Z D,GREGORY M H.A distributed mechanical system simulation platform based on a "Gluing Algorithm"[C].Journal of Computing and Information Science in Engineering,2005,5(1):71-74.
[30]OAKS S,TRAVESRSAT B,GONG L.JXTA技术手册[M].北京:清华大学出版社,2004.
[31]PANTI M,PENSERINI L.A P2P approach to land warriors coordination[R].CTS'03:The 2003International Symposium on Collaborative Technologies and Systems,Orlando of Florida,2003:109-117.
[32]JEAN M S,GREGORY B,CHRISTIAN D J.P2P with JXTA-Java pipes[A].2nd International Conference on Principles and Practice of Programming in Java,Kilkenny of Ireland,2003:208-210.