Dickson K.W. Chiu PhD, SMIEEE Thanks to Dr. Patrick C.K. Hung (UOIT)

1. CSIT600c: Web Services Programming Workflow and BPEL4WS Dickson K.W. Chiu PhD, SMIEEE Thanks to Dr. Patrick C.K. Hung (UOIT)

2. An Illustrative Example • Many airline companies have Web sites with information about their services, e.g., flight schedules • Finding flight and fare information is not simple in automatic business-to-business (B2B) applications • Ref: SELVIDGE, P. 1999. Student posters: Reservations about the usability of airline web sites Paula Selvidge, CHI '99 extended abstracts on Human factors in computing systems Dickson Chiu 2005

3. Proprietary protocol and interface Adapted from: http://www.united.com Adapted from: http://www.cathaypacific.com http://www.itn.net/cgi/air?stamp=NEWCOOKY*itn%2Ford%3DNEWREC,itn/air/united&airline=United&persons=1&air_avail=10&air_class=coach+%28lowest+avail.%29&depart=hkg&dest.0=bos&mon_abbr.0=Feb&date.0=25&hour_ampm.0=5+am&mon_abbr.1=Mar&date.1=29&hour_ampm.1=5+am&ecert_num=&rt_ow=Round+Trip&best_itins=2&return_to=best_itins&searchby=itins http://www.cathaypacific.com/intl/plan/schedules/result/0,3845,,00.html?WAtxn=202&fromShortCut=&language=GB&device=web&tripType=2&d_city=HKG&a_city=BOS&d_month=200502&d_day=25&r_month=200503&r_day=29&cabins=&errorListIndex=&errorList= Dickson Chiu 2005

4. Proprietary result format Adapted from: http://www.cathaypacific.com Adapted from: http://www.united.com Dickson Chiu 2005

5. Airline B Airline A Web Service Web Service Internet Web Service Airline C Business Process Example (Travel Agency) IBM WebSphere Microsoft .Net Check Flight Schedules Check Flight Schedules Check Flight Schedules B2B Applications Decision Making Compare Options Travel Agency Sun Java Dickson Chiu 2005

6. Roadmap to deploy Web Services Standards (e.g. travel agency) Dickson Chiu 2005

7. Roadmap to deploy Web Services Standards (cont.) Dickson Chiu 2005

8. Workflow and Business Process • Workflow is a computer supported business process • A business process contains a set of activities which represent both business tasks and interactions between Web services • Can be traced from the earlier imaging solutions space – document workflow • Early workflow products enabled the automation of human administrative activities very well. • The need for coordinating Web services for different business processes in a loosely coupled business-to-business environment • Now we need to manage end-to-end business process encompasses both human and system interactions. • Business Process Management (BPM) deals with broader issues of ensuring continuous business process improvements • Business process analysis and re-design • Business process implementation • Business process monitoring Dickson Chiu 2005

9. Workflow Management Coalition (WfMC) • Non-profit, international organization of workflow vendors, users, analysts and university/research groups that promotes workflow interoperability standards. • Workflow Reference Model • http://www.wfmc.org Dickson Chiu 2005

10. Web Service Business Process Languages • Need a language to define a model and a grammar for describing the behavior of a business process based on interactions between the process and its Web service interfaces. • Business process definition can be thought of as a template for creating business process instances. • All of the proposed XML workflow languages are based on WSDL service descriptions with extension elements such as: • Business Process Execution Language for Web Services (BPEL4WS) • Web Services Flow Language (WSFL) and Web Services Endpoint Language (WSEL) • XLANG Ref: Business Process Execution Language for Web Services, Version 1.1, 05 May 2003. http://www-106.ibm.com/developerworks/library/ws-bpel/ Dickson Chiu 2005

11. BPEL4WS • Proposed by IBM and Microsoft • Reference: http://www.redbooks.ibm.com/redpieces/abstracts/sg246381.html Dickson Chiu 2005

12. Receive Customer’s Request Invoke Invoke Invoke Airline A’s Airline B’s Airline C’s Web service Web service Web service Reply to Customer ( Results ) Business Process Diagram Dickson Chiu 2005

13. BPEL4WS Listing Dickson Chiu 2005

14. BPEL4WS – Partner Links partnerLinks: It defines the different parties that interact with the business process in the course of processing the order. Dickson Chiu 2005

15. BPEL4WS - variables variables: It defines the data variables used by the process, providing their definitions in terms of WSDL message types. Dickson Chiu 2005

16. BPEL4WS – flow and links flow: It specifies one or more activities to be performed concurrently. Links: It can be used within concurrent activities to define arbitrary control structures. Dickson Chiu 2005

17. BPEL4WS - received received: It allows the business process to do a blocking wait for a matching message to arrive. Dickson Chiu 2005

18. BPEL4WS - invoke invoke: It allows the business process to invoke a one-way or request-response operation on a portType offered by a partner. Dickson Chiu 2005

19. BPEL4WS - assign assign: It can be used to update the values of variables with new data. An <assign> construct can contain any number of elementary assignments. Dickson Chiu 2005

20. BPEL4WS (cont.) Dickson Chiu 2005

21. BPEL4WS - reply reply: It allows the business process to send a message in reply to a message that was received through a <receive>. Dickson Chiu 2005

22. Receive Customer’s Request Invoke Invoke Invoke Airline A’s Airline B’s Airline C’s Web service Web service Web service Reply to Customer ( Results ) BPEL4WS – scenerio summary The combination of a <receive> and a <reply> forms a request-response operation on the WSDL portType for the process. Input Message Web Service Output Message Dickson Chiu 2005