2.2 A Reference Model for Service Oriented

ServiceOrientedArchitecture(SOA)andSpecializedMessagingPatterns1.0ThesisThewidespreademergenceoftheInternetinthemid1990sasaplatformforelectronicdatadistributionandtheadventofstructuredinformationhaverevolutionizedourabilitytodeliverinformationtoanycorneroftheworld.WhiletheintroductionofExtensibleMarkupLanguage(XML)iasastructuredformatwasamajorenablingfactor,thepromiseofferedbySOAPbasedwebservicestriggeredthediscoveryofarchitecturalpatternsthatarenowknownasServiceOrientedArchitecture(SOA).iiServiceOrientedArchitectureisanarchitecturalparadigmanddisciplinethatmaybeusedtobuildinfrastructuresenablingthosewithneeds(consumers)andthosewithcapabilities(providers)tointeractviaservicesacrossdisparatedomainsoftechnologyandownership.Servicesactasthecorefacilitatorofelectronicdatainterchangesyetrequireadditionalmecha-nismsinordertofunction.SeveralnewtrendsinthecomputerindustryrelyuponSOAastheenablingfoundation.TheseincludetheautomationofBusinessProcessManagement(BPM),compositeapplications(applicationsthataggregatemultipleservicestofunction),andthemultitudeofnewarchitectureanddesignpatternsgenerallyreferredtoasWeb2.0iii.Thelatter,Web2.0,isnotdefinedasastaticarchitecture.Web2.0canbegenerallycharacterizedasacommonsetofarchitectureanddesignpatterns,whichcanbeimplementedinmultiplecontexts.ThelistofcommonpatternsincludestheMashup,Collaboration-Participation,SoftwareasaService(SaaS),SemanticTagging(folksonomy),andRichUserExperience(alsoknownasRichInternetApplication)patternsamongothers.Theseareaugmentedwiththemesforsoftwarearchitectssuchastrustingyourusersandharnessingcollectiveintelligence.MostWeb2.0architecturepatternsrelyonServiceOrientedArchitectureinordertofunction.WhendesigningWeb2.0applicationsbasedonthesepatterns,architectsoftenhavehighlyspecializedrequirementsformovingdata.Enterpriseadoptionofthesepatternsrequiresspecialconsiderationsforscalability,flexibility(intermsofmultiplemessageexchangepatterns),andtheabilitytodelivertheseservicestoamultitudeofdisparateconsumers.Architectsoftenneedtoexpanddatainterchangesbeyondsimplerequest-responsepatternsandadoptmorerobustmessageexchangepatterns,triggeredbymultipletypesofevents.Asaresult,manyspecializedplatformsareevolvingtomeettheseneeds.Thiswhitepaperdiscussesspecializationsforadvanceddataexchangeswithinenterpriseserviceorientedenvironmentsandillustratessomeofthecommonarchitecturesofthesenewplatforms.i.TheExtensibleMarkupLanguage(XML)isaW3CRecommendation-://=soa-rmiii.Web2.0isdefinedasasetofDesignPatternsintheO’ReillybookWeb2.0DesignPatterns-:DuaneNickulContributors/Editors:LaurelReitmanJamesWardJackWilberTableofContents1.0Thesis.....................................................................................12.0AnIntroductiontoServiceOrientedArchitecture.........................................................................22.1RequirementsforSOA....................................................22.2AReferenceModelforServiceOrientedArchitecture.........................................................................42.3DecomposingtheInteractionModel.......................53.0AReferenceArchitectureforServiceOrientedArchitecture.........................................................................63.1ServiceTier..........................................................................73.2ClientTier.............................................................................83.3ArchitecturalConventionsspanningmultipletiers.......................................................................93.4Events.................................................................................103.5Objects...............................................................................103.6ArchitecturalPatterns...................................................114.0DataandMessageExchangePatternsforEnterpriseSOA..................................................................114.1Request-Response..........................................................114.2Request-ResponseviaServiceRegistry(orDirectory).....................................................................114.3Subscribe-Push...............................................................124.4ProbeandMatch............................................................124.5PatternsforRIAs.............................................................134.6Datapaging.....................................................................144.7Datapush..........................................................................145.0AFinalWord.....................................................................14AbouttheAuthors...............................................................15TechnicalWhitePaper2.0AnIntroductiontoServiceOrientedArchitectureServiceOrientedArchitecture(SOA)isa