Composing Aggregate Web Services in BPEL

1. Composing Aggregate Web Services in BPEL Onyeka Ezenwoye and S. Masoud Sadjadi Autonomic Computing Research Laboratory School of Computing and Information Sciences Florida International University March 2006 The 44th ACM Southeast Conference

2. Outline Introduction Web Service Technologies BPEL Overview BPEL Shortcomings Conclusion Agenda Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion

3. Outline The Trend Organizations need to integrate applications and data with other divisions, customers, partners, etc. This is commonly known as Enterprise Application Integration (EAI) or Business Process Integration (BPI). Introduction Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion

4. Outline Introduction • The Problem • The existing marketplace is littered with proprietary middleware/protocols (e.g., Java RMI, .NET, CORBA, etc.) for service interaction. • These protocols do not openly support inter-organization service interactions over the internet. Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion

5. Outline A Web service is a software application identified by a URI, whose interfaces and binding are capable of being described and discovered by XML artifacts (documents) supports direct interactions with other software applications using XML based messages via internet-based protocols Core Technologies XML (eXtensible Markup Language) SOAP (Simple Object Access Protocol) WSDL (Web Service Description Language) Web Services Definition by W3C Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion

6. Outline SOAP An XML-based simple protocol for exchanging structured and typed data over the Internet. XML is used for data encoding text-based protocol vs. binary protocol Supports XML-based RPC SOAP is transport independent. A SOAP message consists of the envelope. header + body Web Service Technologies Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion

7. Outline WSDL XML language for describing web services A Web service is described as A set of communication endpoints (ports) Endpoint is made of two parts Abstractdefinitions of operations and messages Concretebinding to networking protocol (and corresponding endpoint address) and message format Why this separation? Enhance reusability and dynamic service locating and binding Web Service Technologies Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion

8. Outline Structure of WSDL <definition namespace = “http/… “> <type> schema for message types</type> <message>+ defines data elements of operations <part>+ components of the message </message> <portType> defines the web service interface <operation>+ operations that can be performed <input> <output> <fault>* </portType> <binding> comms. protocols for operations </binding> <service> a list of binding and ports to the bindings </service> </definition> Web Service Technologies Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion

9. Outline Characteristics of Web Services XML based everywhere Message-based Programming language independent Could be dynamically located Could be dynamically assembled or aggregated Accessed over the internet Loosely coupled Based on industry standards Web Services Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion

10. Outline Business Process Execution Language Workflow language for composing aggregate Web service. XML based A BPEL process is defined in terms of its interactions with its partners. A partner may provide service to the process, require service from the process or both. Widely used Supported by IBM, Microsoft, and BEA. BPEL Overview Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion

11. Outline Service Aggregation (business processes) Agenda Introduction Web Services BPEL Overview Customer Customer BPEL Shortcmgs Conclusion Sales Service (a workflow) Accounting Service Production Service Inventory Service Delivery Service BPEL Overview

12. Outline *A Loan Approval Process < $10,000 >= $10,000 “high” “low” BPEL Overview Client Agenda Introduction Web Service Web Services Web Service BPEL Overview BPEL Shortcmgs Conclusion Client *www.activebpel.org

13. Outline Partners in BPEL <partnerLinks> <partnerLink myRole="approver" name="customer" partnerLinkType="lns:loanApprovalLinkType"/> <partnerLink name="approver" partnerLinkType="lns:loanApprovalLinkType" partnerRole="approver"/> <partnerLink name="assessor" partnerLinkType="lns:riskAssessmentLinkType" partnerRole="assessor"/> </partnerLinks> Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion BPEL Overview

14. Outline Activities in BPEL <process> … <flow> <receive name="receive" partnerLink="customer" …> … </receive> <invoke name="invokeapprover" partnerLink ="approver“ …> … </invoke> <invoke name="invokeAssessor" partnerLink="assessor" …> … </invoke> <reply name="reply" partnerLink="customer" …> … </reply> </flow> </process> Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion Preliminary Study Outline

15. Outline Fault Handling Two constructs for handling faults; <catch> and <catchAll>. No provision for system faults. <catchAll> has no way of distinguishing between faults. Data Manipulation BPEL offers limited data manipulation. Not possible to dynamically create or destroy variables. Localvariables cannot be declared within activity blocks. Not able to recognize when two variables are composed of the same primitive types. BPEL Shortcomings Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion

16. Outline RobustBPEL Onyeka Ezenwoye and S. M. Sadjadi. “Enabling Robustness in Existing BPEL Processes”. In Proceedings of the 8th International Conference on Enterprise Information Systems (ICEIS-06),May 2006. To appear. Questions? Conclusion Agenda Introduction Web Services BPEL Overview BPEL Shortcmgs Conclusion