Interaction Choreography Models in BPEL:Choreographies on the Enterprise Service Bus
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This document summarizes a conference presentation on interaction choreography models expressed using BPEL. It introduces BPELgold, a new language that extends BPEL to support modeling service choreographies and their global order of message exchanges. BPELgold models can be implemented on an Enterprise Service Bus. The presentation evaluates BPELgold and other choreography languages, and concludes by discussing opportunities to improve tooling for BPELgold and further integrate fault handling.
Interaction Choreography Models in BPEL:Choreographies on the Enterprise Service Bus
- 1. S-BPM ONE 2010 - the Subjectoriented BPM Conferencehttp://www.aifb.kit.edu/web/S-bpm-one/2010Interaction Choreography Models in BPEL:Choreographies on the Enterprise Service Bus
- 2. OverviewState of the art in choreography researchMotivation forinteractionmodelsexpressedusing BPELNew language: BPELgoldBPELgoldandthe Enterprise Service BusEvaluation ofBPELgoldConclusion and outlook
- 3. WhyChoreographies?Services may be stateless and statefulBehavior of stateful services may be described using …TextualdescriptionsAbstract WS-BPEL processesOperating GuidelinesWhatabouttheinteractionbetweentwoormoreservices?Business protocolChoreography
- 5. Introduction to Service ChoreographiespublicviewModeling Language used:BPMN 2.0 asof 2010-06-05publicviewInterconnected public viewsAlternatively: Interconnected participant behavior descriptions Interconnection models (“collaboration” in BPMN 2.0)Detailedcomparisonbetweenorchestration, interfacebehavior (publicview) andchoreographyisprovidedat:Dijkman, R. & Dumas, M. Service-oriented Design: A Multi-viewpoint ApproachInternational Journal of Cooperative Information Systems, 2004, 13, 337-368
- 6. Alternative Modeling ApproachInteractions globally capturedBasic building block:atomicinteraction between two parties Interaction models (“choreography” in BPMN 2.0)Detaileddiscussion: Decker, G. & Weske, M. Interaction-centric Modeling of Process Choreographies Information Systems, 2010
- 8. Properties of Interaction ModelsRealizabilityThere exist orchestrations showing equivalent behavior as the choreographySynchronous communication changes to asynchronous communicationAll interactions have to be produced by the orchestrationsOrchestrations may not introduce additional communicationDecker, G. & Weske, M. Local Enforceability in Interaction Petri Nets Business Process Management, Springer Berlin / Heidelberg, 2007, 4714, 305-319
- 9. Properties of Interaction ModelsLocal enforceabilityWeaker than realizabilityContain only interactions specified in the choreographyAre able to enforce all constraints expressed in the global modelDecker, G. & Weske, M. Local Enforceability in Interaction Petri Nets Business Process Management, Springer Berlin / Heidelberg, 2007, 4714, 305-319
- 10. Properties of Interaction ModelsDesynchronizabilityStrong than realizability Orchestrations together “weakly terminate”Example for non-desynchronizability: mixed choicesDecker, G.; Barros, A. P.; Kraft, F. M. & Lohmann, N.: Non-desynchronizable Service ChoreographiesISCOC 2008: 6th International Conference on Service-Oriented Computing,
- 11. Evaluation of Choreography LanguagesService Interaction PatternsWhat kind of interactions have to be supported by the language?Send/receive, one-from-many receive, relayed request“Requirements Framework” Multi-literal interactionsService SetsService TopologyBarros, A.; Dumas, M. & ter Hofstede, A. Service Interaction PatternsProceedings 3rd International Conference on Business Process Management (BPM), SpringerDecker, G.; Kopp, O.; Leymann, F. & Weske, M. Interacting services: From specification to executionData & Knowledge Engineering, Elsevier Science Publishers, 2009, 68, 946-972
- 12. Requirements on Choreography Languages (1)Multi-lateral InteractionsMore than two participantsService topologyList of participants and their linksService setsSets of same type of participantsPossibly a priory unknown sizeSelection of services and reference passingLink passing mobilitySpecification of message formatsMessage formats can be standardizedDecker, G.; Kopp, O.; Leymann, F. & Weske, M. Interacting services: From specification to executionData & Knowledge Engineering, Elsevier Science Publishers, 2009, 68, 946-972
- 13. Requirements on Choreography Languages (2)Interchangeability of technical configurationsThe protocol stays the same, but the port types changeTime constraintsE.g., specification of behavior due to timeoutsException handlingCapable of expressing derivations of the “happy path”CorrelationIdentification of the right „choreography instance“Integration with orchestration languagesWS-BPEL compatibilityDecker, G.; Kopp, O.; Leymann, F. & Weske, M. Interacting services: From specification to executionData & Knowledge Engineering, Elsevier Science Publishers, 2009, 68, 946-972
- 14. Evaluation ofExistingLanguagesKopp, O.; Leymann, F. & Wagner, S. Modeling Choreographies: BPMN 2.0 versus BPEL-based Approachessubmitted to Wirtschaftsinformatik 2011
- 15. Current Available LanguagesBPELgold: BPEL globaldefinitionBPEL4Chor: BPEL for choreographies
- 16. BPELgold
- 17. ParticipantTopologyResuedandadpatedfromBPEL4ChorList ofparticipanttypes<topology name="investment" gld:interactionDescription="inv:interactions"> <participantTypes> <participant name="Consultant" /> <participant name="Customer" /> </participantTypes> <participants> <participant name="consultant" type="Consultant" /> <participant name="customer" type="Customer" /> </participants> <messageLinks> <messageLink name="investmentProposal" sender="consultant" receiver="customer" /> <messageLink name="acceptance" sender="customer" receiver="consultant" /> <messageLink name="rejection" sender="customer" receiver="consultant" /> </messageLinks></topology>List ofparticipantsConnectingparticipants
- 18. Interaction DescriptionNew extensionactivitymodelingatomic interactions<process> <sequence> <extensionActivity> <gld:interactionmessageLink="investmentProposal" /> </extensionActivity> <wait for="P1D" /> <pick> <gld:onInteractionmessageLink="acceptance" /> <gld:onInteractionmessageLink="rejection" /> </pick> </sequence></process>New extensionsupportingchoices on atomic interactions
- 19. Usage in the Enterprise Service BusKopp, O.; van Lessen, T. & Nitzsche, J. The Need for a Choreography-aware Service Bus, YR-SOC 2008
- 21. Whatif a Violation Occurs?A violation triggers ODEgold to throw a gld:choreographyViolation faultThisindicates non-complianceoftheexecutiontothechoreography modelA fault leads to a termination of the choreographyAlternative behavior desiredFault handler may be used to specify the alternative behaviorFull BPEL scope semanticsInteraction with the service bus is enabledUnique toBPELgold, not existing in BPMN, …
- 22. UsageofBPELgold
- 24. Conclusionand OutlookBPELgold as interaction choreography language based on BPELEnables interaction modeling using BPEL’s execution semanticsImprovements of toolingODEgoldBPELgoldmodeller (based on Oryx)Mappings to/from BPELgoldIntegration of cross-partner fault handling concepts in BPELgoldContact: http://www.iaas.uni-stuttgart.de/institut/mitarbeiter/kopp/
- 26. Evaluation ofCurrentLanguagesDecker, G.; Kopp, O.; Leymann, F. & Weske, M. Interacting services: From specification to executionData & Knowledge Engineering, Elsevier Science Publishers, 2009, 68, 946-972
- 27. Verificationof BPEL4Chor and BPELBPEL4Chor VerificationLohmann, N.; Kopp, O.; Leymann, F. & Reisig, W.Analyzing BPEL4Chor: Verification and Participant SynthesisWS-FM 2007, Springer-Verlag, 2007Verification respecting data dependenciesMonakova, G.; Kopp, O.; Leymann, F.; Moser, S. & Schäfers, K.Verifying Business Rules Using an SMT Solver for BPEL ProcessesProceedings of the Business Process and Services Computing Conference: BPSC'09, Gesellschaftfür Informatik e.V. (GI), 2009Overview on all verifications (as of 2006):van Breugel, F. & Koshkina, M. Models and Verification of BPELhttp://www.cse.yorku.ca/~franck/research/drafts/tutorial.pdf2006
- 28. Further ReadingDecker, G.; Kopp, O. & Barros, A.An Introduction to Service ChoreographiesInformation Technology, OldenbourgVerlag, 2008, 50, 122-127Decker, G.Design and Analysis of Process ChoreographiesPhD thesis, HassoPlattner Institute, University of Potsdam, 2009Kopp, O.; Wieland, M. & Leymann, F. Towards Choreography TransactionsZEUS 2009, CEUR-WS.org, 2009, 438Kopp, O.; Martin, D.; Wutke, D. & Leymann, F.The Difference Between Graph-Based and Block-Structured Business Process Modelling LanguagesEnterprise Modelling and Information Systems, Gesellschaftfür Informatik e.V. (GI), 2009, 4, 3-13Lohmann, N.; Massuthe, P. & Wolf, K.Operating Guidelines for Finite-State ServicesICATPN 2007, Springer, 2007