基于企业门户的应用集成研究
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摘要
作为一种整合、分类、集成和访问企业信息的方法，企业门户为企业的员工、客户、供应商和合作伙伴提供了一个获取企业内部信息的统一平台。企业门户不仅集成企业的信息资源，同时也集成企业的各种应用系统。
企业门户进行应用集成的关键是解决应用间的互操作问题。而在门户中，每个应用都是以Portlet的方式来呈现的，因此首先必须支持Portlet间的互操作。这就要求必须满足下面的三个条件：Portlet间交换的应用数据具有统一的模型；Portlet间具有统一的应用调用接口；Portlet之间能够互相通信。而当前的Portlet规范并未提供这三个方面的支持，因此有必要对该规范进行扩展。
本文研究了当前的Portlet规范，针对其在Portlet互操作支持上的不足，对Portlet容器进行了扩充，并在此基础上提出了一种基于企业门户的应用集成框架。在该框架内部，利用Portlet对应用进行包装，解决数据模型和调用接口不一致的问题；然后通过与Portlet容器中协作逻辑的交互，来实现不同Portlet的间接通信，从而最终实现集成应用间的协同工作。
基于这个应用集成框架，我们在自主开发的企业门户OncePortal中实现了应用集成框架的原型。该原型对PortletAPI进行扩充，提供统一的集成应用数据模型IADM和统一的集成应用接口交互模型IAIM来对应用进行包装：然后在Portlet容器中以规则的形式定义Portlet间的协作逻辑，并以Portlet容器作为交互的中介，间接实现集成应用间的通信。
此外，作为应用集成的一部分，本文针对企业门户的集成特性提出了一种单点登录机制，使得企业用户只需完成门户上的一次认证就可以访问其内部的多个授权应用。在OncePortal的应用集成框架原型中，我们针对采用标准认证方式的应用实现了一个基于凭证库的单点登录子系统。
As a solution to the information assembling, categorizing and integrating , Enterprise Portal (EP) provides its users, such as employees, clients, vendors and partners, with a uniform platform to access its internal information. Besides information resources, Enterprise Portal must be able to integrate application systems of all kinds.
The key of application integration through Enterprise Portal is to resolve the interoperability between applications. However, each application is represented by a portlet, so it's required to provide the interoperability between different portlets. For portlets, the following three must be met: canonical data model, canonical API and the ability to communicate with each other. All these above have not been supported in the present portlet specification, and it is needed to extend the specification to provide this support.
In this paper, we analyzed Portlet Specification, pointed out the insufficiencies, and then proposed an Enterprise Portal-based application integration framework, which was the extension of portlet container . In this framework, applications were wrapped by portlets, so we removed the inconsistency on data models and interfaces. In addition, different portlets could communicate with each other by interacting with the coordination logic of portlet container. In this way, applications could be integrated to work together.
Basing on the framework above, we implemented a prototype for application integration in OncePortal, an enterprise portal developed independently by ourselves. Firstly, this prototype extended Portlet API, then provided a canonical data model(IADM) and an interaction model(IAIM) for integrated applications to wrap them. Secondly, coordination logic between portlets could be defined by a set of rules in portlet container, and different applications could communicate indirectly with each other using portlet container as the mediator.
Besides, as part of application integration, a kind of single sign-on mechanism specific to EP was also proposed in this paper . Under SSO, users authenticate themselves only once and are logged into applications without further manual interaction. In the prototype framework, we implemented a credential-based SSO sub-system for the application systems which adopted standard authentication mechanism.
企业门户进行应用集成的关键是解决应用间的互操作问题。而在门户中，每个应用都是以Portlet的方式来呈现的，因此首先必须支持Portlet间的互操作。这就要求必须满足下面的三个条件：Portlet间交换的应用数据具有统一的模型；Portlet间具有统一的应用调用接口；Portlet之间能够互相通信。而当前的Portlet规范并未提供这三个方面的支持，因此有必要对该规范进行扩展。
本文研究了当前的Portlet规范，针对其在Portlet互操作支持上的不足，对Portlet容器进行了扩充，并在此基础上提出了一种基于企业门户的应用集成框架。在该框架内部，利用Portlet对应用进行包装，解决数据模型和调用接口不一致的问题；然后通过与Portlet容器中协作逻辑的交互，来实现不同Portlet的间接通信，从而最终实现集成应用间的协同工作。
基于这个应用集成框架，我们在自主开发的企业门户OncePortal中实现了应用集成框架的原型。该原型对PortletAPI进行扩充，提供统一的集成应用数据模型IADM和统一的集成应用接口交互模型IAIM来对应用进行包装：然后在Portlet容器中以规则的形式定义Portlet间的协作逻辑，并以Portlet容器作为交互的中介，间接实现集成应用间的通信。
此外，作为应用集成的一部分，本文针对企业门户的集成特性提出了一种单点登录机制，使得企业用户只需完成门户上的一次认证就可以访问其内部的多个授权应用。在OncePortal的应用集成框架原型中，我们针对采用标准认证方式的应用实现了一个基于凭证库的单点登录子系统。
As a solution to the information assembling, categorizing and integrating , Enterprise Portal (EP) provides its users, such as employees, clients, vendors and partners, with a uniform platform to access its internal information. Besides information resources, Enterprise Portal must be able to integrate application systems of all kinds.
The key of application integration through Enterprise Portal is to resolve the interoperability between applications. However, each application is represented by a portlet, so it's required to provide the interoperability between different portlets. For portlets, the following three must be met: canonical data model, canonical API and the ability to communicate with each other. All these above have not been supported in the present portlet specification, and it is needed to extend the specification to provide this support.
In this paper, we analyzed Portlet Specification, pointed out the insufficiencies, and then proposed an Enterprise Portal-based application integration framework, which was the extension of portlet container . In this framework, applications were wrapped by portlets, so we removed the inconsistency on data models and interfaces. In addition, different portlets could communicate with each other by interacting with the coordination logic of portlet container. In this way, applications could be integrated to work together.
Basing on the framework above, we implemented a prototype for application integration in OncePortal, an enterprise portal developed independently by ourselves. Firstly, this prototype extended Portlet API, then provided a canonical data model(IADM) and an interaction model(IAIM) for integrated applications to wrap them. Secondly, coordination logic between portlets could be defined by a set of rules in portlet container, and different applications could communicate indirectly with each other using portlet container as the mediator.
Besides, as part of application integration, a kind of single sign-on mechanism specific to EP was also proposed in this paper . Under SSO, users authenticate themselves only once and are logged into applications without further manual interaction. In the prototype framework, we implemented a credential-based SSO sub-system for the application systems which adopted standard authentication mechanism.
引文
[1]. Portlet API Specification 1.0, October 27, 2003
[2]. S. Hepper, S. Hesmer, "Introducing the portlet specification" http ://www.javaworld.com/javaworld/jw-08-2003/jw-0801-portlet.html
[3]. G. Eaglesfield, "The Enterprise Portal Reference Architecture White Paper", November 2001, http://www.transflow.co.uk
[4]. M. Rosendahl, E. Rune, "Enterprise Application Integration-Strategies for the Telecommunication Market", Uppsala and KTH Master's Thesis in Computing Science 176 Examensarbete IT3, 2000-10-YY, ISSN 1100-1836
[5]. P. Johannesson, E. Perjons, "Design Principles for Application Integration", B. Wangler, L. Bergrnan (Eds.): CaiSE 2000, LNCS 1789, pp.212-231, 2000, Springer-Verlag Berlin Heidelberg 2000
[6]. Scott W. Ambler, "How to reuse your legacy investments within Java Applications",http://www-900.ibm.com/developerWorks/cn/java/com/tip-leg/index eng.shtml
[7]. [7]G. Shi, "Data Integration using Agent based Mediatro-Wrapper Architecture", Tutorial Report for Agent Based Software Engineering, December 17, 2002
[8]. E.Gamma, R. Johnson, Design Patterns: Elements of Reusable Object-Oriented Software,Addison-Wesley, October1994
[9]. M.T.Ozsu, P.Valduriez, Principles of Distributed Database Systems 2nd Edition, Prentice Hall, 1999
[10]. Q.Situ, E.Stroulia, "Task-Structure Based Mediation: The Travel-Planning Assistant Example", Proceedings of the 13th Canadian Conference on Artificial Intelligence (AI'2000), 14-17 May, 2000, pp.400-410, Montreal, Quebec, Canada.
[11]. H.Zhang, E.Stroulia, "Babel: Application Integration through XML specification of Rules", 23rd International Conference on Software Engineering (ICSE 2001), 12-19 May 2001,Toronto, Canada, 831-832. IEEE Computer Society Press.
[12]. M.Roth, P.Schwarz, "Don't Scrap It, Wrap it! A Wrapper Architecture for Legacy Data Sources", Proceedings of 23rd VLDB Conference Athens, Greece, 1997.
[13]. J.D.Clercq, "Single Sign-On architectures", In Geoge I.Davida, Yair Frankel, and Owen Rees, editors, Infrastructure Security, International Conference, InfraSec 2002 Bristol, UK,October 1-3, 2002, Proceedings, volume 2437 of Lecture Notes in Computer Science,pages 40-58. Springer Verlag, 2002.
[14]. C.Dunne, "Build and implement a single sign-on solution",http://www-106.ibm.com/developerworks/web/librarv/wa-singlesign/?Open&ca=daw-ad-news.
[15]. A. Pashalidis, C. J. Mitchell. "A taxonomy of single sign-on systems". In R. Safavi-Naini
and J. Seberry, editors, Information Security and Privacy, 8th Australasian Conference, ACISP 2003, Wollongong, Australia, July 9-11, 2003, Proceedings, volume 2727 of Lecture Notes in in Computer Science, pages 249-264. Springer-Verlag, Berlin, July 2003.
[16]. "Kerberos: The Network Authentication Protocol",http://web.mit.edu/kerberos/www/
[17]. Gary Tagg, "Implementing a Kerberos Single Sign-on Infrastructure",http://www.tagg-consulting.co.uk/kerberos.pdf
[18]. XSL Transformations(XSLT) Version 1.0,http://www.w3c.org/TR/xslt
[19]. C.Lai, L.Gong, L.Koved, A. Nadalin, R.Schemers, "User Authentication and Authorization in the JAVA Platform", Proceedings of the 15th Annual Computer Security Applications Conference, Phoenix, AZ, December 1999.
[20]．徐家骏，贾文玉，企业信息门户EIP，机械工业出版社，2004
[21]．Portal应用集成分析，中科院软件所软件工程中心Portal组
[22]．朱贵东，基于中间件的应用集成研究，中科院软件所硕士学位论文，2001
[23]．OncePortal总体设计报告，中科院软件所软件工程中心Portal组
[24]．马树奇，J2EE编程指南1．3版，电子工业出版社，2002
[25]．谈猛刚，李剑等，“XTRANS：一个XML与关系数据库相互转换系统”，计算机工程与应用，已录用
[2]. S. Hepper, S. Hesmer, "Introducing the portlet specification" http ://www.javaworld.com/javaworld/jw-08-2003/jw-0801-portlet.html
[3]. G. Eaglesfield, "The Enterprise Portal Reference Architecture White Paper", November 2001, http://www.transflow.co.uk
[4]. M. Rosendahl, E. Rune, "Enterprise Application Integration-Strategies for the Telecommunication Market", Uppsala and KTH Master's Thesis in Computing Science 176 Examensarbete IT3, 2000-10-YY, ISSN 1100-1836
[5]. P. Johannesson, E. Perjons, "Design Principles for Application Integration", B. Wangler, L. Bergrnan (Eds.): CaiSE 2000, LNCS 1789, pp.212-231, 2000, Springer-Verlag Berlin Heidelberg 2000
[6]. Scott W. Ambler, "How to reuse your legacy investments within Java Applications",http://www-900.ibm.com/developerWorks/cn/java/com/tip-leg/index eng.shtml
[7]. [7]G. Shi, "Data Integration using Agent based Mediatro-Wrapper Architecture", Tutorial Report for Agent Based Software Engineering, December 17, 2002
[8]. E.Gamma, R. Johnson, Design Patterns: Elements of Reusable Object-Oriented Software,Addison-Wesley, October1994
[9]. M.T.Ozsu, P.Valduriez, Principles of Distributed Database Systems 2nd Edition, Prentice Hall, 1999
[10]. Q.Situ, E.Stroulia, "Task-Structure Based Mediation: The Travel-Planning Assistant Example", Proceedings of the 13th Canadian Conference on Artificial Intelligence (AI'2000), 14-17 May, 2000, pp.400-410, Montreal, Quebec, Canada.
[11]. H.Zhang, E.Stroulia, "Babel: Application Integration through XML specification of Rules", 23rd International Conference on Software Engineering (ICSE 2001), 12-19 May 2001,Toronto, Canada, 831-832. IEEE Computer Society Press.
[12]. M.Roth, P.Schwarz, "Don't Scrap It, Wrap it! A Wrapper Architecture for Legacy Data Sources", Proceedings of 23rd VLDB Conference Athens, Greece, 1997.
[13]. J.D.Clercq, "Single Sign-On architectures", In Geoge I.Davida, Yair Frankel, and Owen Rees, editors, Infrastructure Security, International Conference, InfraSec 2002 Bristol, UK,October 1-3, 2002, Proceedings, volume 2437 of Lecture Notes in Computer Science,pages 40-58. Springer Verlag, 2002.
[14]. C.Dunne, "Build and implement a single sign-on solution",http://www-106.ibm.com/developerworks/web/librarv/wa-singlesign/?Open&ca=daw-ad-news.
[15]. A. Pashalidis, C. J. Mitchell. "A taxonomy of single sign-on systems". In R. Safavi-Naini
and J. Seberry, editors, Information Security and Privacy, 8th Australasian Conference, ACISP 2003, Wollongong, Australia, July 9-11, 2003, Proceedings, volume 2727 of Lecture Notes in in Computer Science, pages 249-264. Springer-Verlag, Berlin, July 2003.
[16]. "Kerberos: The Network Authentication Protocol",http://web.mit.edu/kerberos/www/
[17]. Gary Tagg, "Implementing a Kerberos Single Sign-on Infrastructure",http://www.tagg-consulting.co.uk/kerberos.pdf
[18]. XSL Transformations(XSLT) Version 1.0,http://www.w3c.org/TR/xslt
[19]. C.Lai, L.Gong, L.Koved, A. Nadalin, R.Schemers, "User Authentication and Authorization in the JAVA Platform", Proceedings of the 15th Annual Computer Security Applications Conference, Phoenix, AZ, December 1999.
[20]．徐家骏，贾文玉，企业信息门户EIP，机械工业出版社，2004
[21]．Portal应用集成分析，中科院软件所软件工程中心Portal组
[22]．朱贵东，基于中间件的应用集成研究，中科院软件所硕士学位论文，2001
[23]．OncePortal总体设计报告，中科院软件所软件工程中心Portal组
[24]．马树奇，J2EE编程指南1．3版，电子工业出版社，2002
[25]．谈猛刚，李剑等，“XTRANS：一个XML与关系数据库相互转换系统”，计算机工程与应用，已录用