MastersThesisOpenCodeTranslationfromExecutableandTranslatableUMLModel - PDF document

MastersThesisOpenCodeTranslationfromExecutableandTranslatableUMLModels-ImplicitBridgingbyMikaelLofqvistRegnr:LiTHIDA/DSEX07/004SELinkoping2007 MastersThesisOpenCodeTranslationfromExecutableandTranslatableUMLModels-ImplicitBridgingbyMikaelLofqvistRegnr:LiTH-IDA/DS-EX{07/004SESupervisor:ErikWedinExaminer:ErikLarssonLinkopingApril16,2007. AbstractWhenobject-orientedprogrammingbecameasuccess,theneedformethodstosupportsoftwaredevelopmentfollowed.Inthebeginningofthe1990smorethan50methodsandmodelinglanguageswereavailable,andagrowingproblembecamendingasinglelanguagetofulltheneedsofmanydierentpeopleandprojects.Inthemid-1990s,themodelinglanguagesstartedtoincorporatethebestfeaturesofpreviouslanguages,andfewlanguagesgainedprominenceovertheeld.TheseincludedOOSE(Object-OrientedSoftwareEngineering),OMT(ObjectModelingTechnique),andBooch.Eachofthesemethodshaditsownnotation,processandtools.TheUniedModelingLanguage,UML,wasadoptedunanimouslybythemembershipoftheOMGasastandardinNovember1997touniformthemodelinglanguages.ExecutableandTranslatableUML(xtUML)isthenextabstractionlevelinsoftwaredevelopment,wherebothprogramminglanguageandsoftwarearchitecturehavebeenabstractedaway.ExecutableandTranslatableUMLisawelldenedUMLprole,extendedwithpreciseactionsemantics.Thisallowsthedeveloperstodeneaproblemarea,domain,insuchadetailthatitcanbeexecuted.BydeningthesystemwithxtUML-models,domains,thesystemfunctionalitycanbeveriedearlyinthedevelopmentprocess.ExecutableandTranslatableUMLmodelscanwithoutchangebetranslatedintodierentsoftwareenvironments.Translationtocodecanbedoneindierentwaysandthisworkwillbeperformedinanenvironmentwherecodeisautomaticallygeneratedwithamodelcompiler.Thegoalwithadomainisthatitshouldbeindependentofotherdomains,reusedwithoutmodicationandexchangedwithanotherdomainsolvingthesameprob-lem.Howeveradomaincanmakeassumptionsthatcertainfunctionalityisavailableandtheseassumptionsarerequirementsforanotherdomain.Tofullthesegoalstheremustbeaminimalcouplingbetweenthedomains.ThiscanbesolvedwiththetechniqueImplicitBridging,wherethebridgedependencybetweendomainsisdenedinabridge.Thedependencyisintheformofmap-pings/couplingbetweenelementsinbothdomains.Bydeningabridgeinterfaceforaserverdomainaclientdomaincanusetheresourcesoeredbytheserverdomain.Theresourcesthataclientdomainwishestousearedeclaredinabridgeleandthisleisuniqueforeveryclient-serverpair.Ifanolddomainisexchangedi withanewdomainonlythebridgeleneedstobereplaced.TheworkperformedshowshowanimplementationofImplicitBridgingcouldberealizedbyapplyingthetechniqueinamicrowaveovensystem.Fromthesys-temdesignvedierentmappingtypeshavebeenimplemented.Theapplicabilityandthequalityoftheimplementationhavebeenveriedbytestingthegener-atedsystemfunctionalityandalsoverifyingthegoals,exchangeabilityandreuseofdomains,ofthesystem.Keywords:ExecutableandTranslatableUML,xtUML,Implicit/ExplicitBridg-ing,ModelCompilers,Domains,ModelDrivenDevelopment,CodeTransla-tion,Ada95.ii SammanfattningMeddenobjektorienteradeprogrammeringensframganguppkomettbehovavmetoderforattstodjadennatypavmjukvaruutveckling.Iborjanav1990-taletfannsdetett50-talmetoderochmodelleringsspraktillgangliga.Medokningenavantaletmetoderokadeavenproblemetatthittaenmetodsomkundeuppfyllabehovetforbademanniskorochprojekt.Imittenpa1990-taletborjadedenyametodernaanvandasigavdebastadelarnafransinaforegangare,vilketresulteradeiattettfatalmetoderckovertaget,tillexempelOOSE(Object-OrientedSoftwareEngineering),OMT(ObjectModelingTechnique),andBooch.Dessametoderhadevarochensinegennotation,processochverktyg.ForattenamodelleringssprakenantogsUML,theUniedModellingLanguage,somstandardavOMG1997.ExecutableandTranslatableUML(xtUML)arnastaabstraktionsnivainommjuk-varuutvecklingen,darbadeprogramsprakochmjukvaruarkitekturharabstraheratsbort.xtUMLarenvaldenieradprolinomUML,utokadmedenaktionsemantik.Dettatillaterutvecklarnaattdenieraproblemomraden,domaner,isadande-taljattdekanexekveras.GenomattdenierasittsystemmedxtUML-modeller,domaner,kanmanpaetttidigtstadiumverierasystemetsfunktionalitet.xtUMLkanoversattastillolikamjuvaruplattformarutanattnagraandringarimodellernabehovsgoras.Oversattningtillprogramkodkangoraspa\rerasattochdettaar-betekommerattutforasienmiljodarkodautomatisktgenererasmedhjalpavenmodellkompilator.Maletmeddomanerarattdeskavaraoberoendeavvarandra,kunnaateranvandasutanmodikationochersattasmedenannandomansomlosersammaproblem.Daremotkanendomangoraantagandenattenvissfunktionalitetnnsatttillgaochdessaantagandenarkravforenannandoman.Forattmaletskakunnauppfyllasmastedomanernahaenminimalkopplingmellansig.DettakanlosasmedhjalpaventekniksomheterImplicitBridging,darmandenierarberoendetmellandomaneriensakalladbrygga.Beroendetariformavkopplingar(mappningar)mellanelementidebadadomanerna.Genomattdenieraettservergranssnittforentjanstedomankanmanlataeneller\reraklientdomaneranvandaderesursersomtjanstedomanenerbjuder.Deresursermanvillanvandadeklarerasienbrygglsomarunikforvarjeklient-serverpar.Ommanskulleviljabytautendomansaardetbaraattersattadengamladomaneniii ochskrivaennybryggl.DetarbetesomutfortsvisarhurenimplementationavImplictBridgingkangenom-forasgenomatttillampateknikeniettsystemforenmikrovagsugn.Utifransystemetsdesignharfemolikatyperavmappningarimplementerats.Teknikenstillampbarhetochimplementeringenskvalitetharverieratsgenomatttestadetgenereradesystemetsfunktionalitet,samtattmaletmedattenkeltkunnabytaut,ateranvandaellertabortdomanerisystemetuppfylls.Nyckelord:ExecutableandTranslatableUML,xtUML,Implicit/ExplicitBridg-ing,ModelCompilers,Domains,ModelDrivenDevelopment,CodeTransla-tion,Ada95.iv AcknowledgmentFirstofall,IwouldliketothankmysupervisorErikWedinforhissupport,myexaminerErikLarssonandbothAndersErikssonandStefanWidingfortheirhelpmakingthingswork.Secondly,IwouldliketothankJohanBorgforhisfeedbackaboutthisreport.Finally,Iwouldliketothankmywife,Ulrika,forherpatienceandkindness.v vi Contents1Introduction31.1Background................................31.2Objective.................................31.3Environment...............................41.4Goal....................................51.5Delimitation................................51.6Literature.................................51.7Convention................................51.8Terminology................................51.8.1CommonTerms..........................61.9ThesisOutline..............................62Background72.1ExecutableandTranslatableUML...................72.1.1WhyUseExecutableandTranslatableUML(xtUML)?...82.1.2Model-DrivenArchitecture...................82.1.3Domains..............................82.1.4ExecutableandTranslatableUMLMetamodel........92.2Bridging..................................102.2.1ExplicitBridging.........................112.2.2ImplicitBridging.........................113AutomaticCodeGeneration133.1VisualLanguages.............................133.2VisualProgramingEnvironments....................13vii viiiContents 3.3DesignModels..............................143.3.1StructuralApproach.......................143.3.2BehaviouralApproach......................143.3.3TranslativeApproach......................153.4CodeTranslation.............................173.4.1CodeGeneration.........................173.4.2ModelCompilers.........................183.4.3OpenTranslation.........................183.4.4TranslationProcess.......................194MicrowaveOvenSystem214.1Purpose..................................214.2Functionality...............................224.2.1Domains..............................234.2.2MicrowaveOven.........................234.2.3UserInterface...........................234.2.4Test................................234.2.5GraphicalUserInterface.....................235AnalysisforImplicitBridging275.1Howtheimplementedmappingswerefound..............275.2CounterpartObjectMapping......................295.2.1Description............................295.2.2DesignDecisions.........................295.3CounterpartEventMapping.......................325.3.1Description............................325.3.2DesignDecisions.........................335.4CounterpartAttributeMapping.....................365.4.1Description............................365.4.2DesignDecisions.........................365.5StateToAttributeValueMapping...................395.5.1Description............................395.5.2DesignDecisions.........................395.6NewStateTransitionToAttributeValueMapping..........40 Contentsix 5.6.1Description............................405.6.2DesignDecisions.........................416ImplementationofImplicitBridging436.1MicrowaveOvenSystem.........................436.1.1MicrowaveOven.........................436.1.2UserInterface...........................436.1.3Test................................446.1.4GraphicalUserInterface.....................456.2HowtheMappingswereImplemented.................466.3MappingImplementation........................486.3.1CounterpartObjectMapping..................486.3.2CounterpartEventMapping...................516.3.3CounterpartAttributeMapping................526.3.4StateToAttributeValueMapping...............536.3.5NewStateTransitionToAttributeValueMapping......546.4HowtheMappingInformationisStored................566.5HowtheMappingInformationisUsed.................576.6MappingLimitations...........................586.6.1TranslationProcess.......................587Evalutation617.1VericationofImplementation.....................617.1.1ImplementedMappings.....................617.1.2Systemgeneration........................617.1.3Vericationoffunctionality...................617.2EarlierImplementation..........................637.2.1Functionality...........................637.2.2Comparison............................637.3ImplicitBridgingWork\row.......................657.4ErrorManagement............................668Summary678.1Conclusion................................67 xContents 8.2FutureWork...............................698.2.1FutureMappings.........................698.2.2ErrorManagement........................69ABridgeMetamodel71BMicrowaveModel75CUserInterfaceModel77DTestModel81EMicrowaveSystem-DomainChart83 Contents1 ListofFigures2.1Domaintypes...............................92.2Aclientandserverdomaindependency.................102.3Bridgemappings..............................103.1Translationprocess............................194.1Thegraphicaluserinterface........................224.2Thedoorisopen..............................244.3Themicrowaveoveniscooking......................244.4Themicrowaveovenisidle........................255.1TheCounterpartObjectMapping....................295.2ACOMbetweentwoobjects.......................305.3ACOMbetweenseveralobjects.....................305.4ACOMsequence.............................315.5AcyclicCOMsequence..........................315.6PossibleCounterpartEventMapping..................325.7Cycliceventgeneration..........................335.8ACEMwithmorethanonecounterpartevents.............345.9ACEMsequencewithmorethantwocounterpartevents.......345.10ApossibleCounterpartAttributeMapping...............365.11Possibleattributetypemappings.....................375.12Tabelofalloweddatatypestobemapped................385.13AStateToAttributeValueMapping..................395.14TwoNSTTAVMstothesameattribute................405.15TwoNSTTAVMstothesameattribute................416.1Thetestsequence.............................456.2AbridgemodelfortheSTAVM.....................466.3AhalftablefortheSTAVM........................476.4Theclientandserverlemodel.....................586.5Translationprocess............................59 2Contents Chapter1IntroductionThegoalofthischapteristogivethereaderanintroductiontothethesisanditsbackground.Thestructureofthethesisispresentedandnecessarydelimitationsareexplained.1.1BackgroundThismaster'sthesiswaswrittenasanalyearprojectforcompletionofaMasterofScienceinComputerScienceandEngineeringatLinkopingUniversity,Swe-den.ThisworkwasperformedinthedepartmentofSoftwareArchitectureandDevelopmentatSAABBoforsDynamics(SBD),Linkoping.SincesomeyearsbackastudyinmodelbaseddevelopmentandautomaticcodegenerationhasbeenperformedatSBD.ThisprojectisacontinuationofthisstudyandthepurposeistoinvestigateandimplementthetechniqueImplicitBridg-ingbetweendomainsinExecutableandTranslatableUML(xtUML).Inshortthismeansthattwoindependentdomains(xtUML-models)aremappedtogetherwith-outchangingtheircontents.Whengeneratingcodethesemappingsareusedtogeneratecodethatisamixtureofbothdomains.1.2ObjectiveTheobjectivesofthisthesisaretoinvestigateandimplementthetechniqueImplicitBridging.ThethesisisacontinuationofastudyinmodelbaseddevelopmentandopencodetranslationthathasbeenperformedatSBDsince2001.TomakeuseofthisdevelopmentprocessanditsbenetsitisveryimportantthattheImplicitBridgingtechniqueisused.Thistechniquesolvestheproblemswithreduceddo-mainindependencybyminimizingthecouplingbetweendomains.Thisisdoneby3 4Introduction removingexplicitreferencesbetweendomainsinterfacesinthemodelsandinsteadlettheArchitecture(ModelCompiler)insertnecessaryinformation.Thereisnostraightforwardimplementationforimplicitbridginganditisstronglycoupledtothearchitecturewereitisimplemented.Animplementationiseitherveryexpensivetobuyoritisinhousedeveloped.Thereforetheavailabilityofinformationthatdescribesthetechniqueandspeciallyimplementationdetailsisverylimited.Thereexistsonepreviousimplementationofimplicitbridginginthecurrentarchi-tecture.Thisimplementationistosomeextentlimitedandthemainreasonfortheimplementationistoshedlightonthetechnique.Thethesisworkwillnotbebasedonthisimplementationmainlybecauseanewapproachiswanted.Thethesisworkwasdividedintoatheorypartandapracticalpart.Inthetheorypartthetechniquewasinvestigatedandinthepracticalparttheinvestigationresultedinanimplementation.Thetheorypartwasfurtherdividedintotwosubparts:ExecutableandTranslatableUMLBridgingandSBDxtUML/Adamodelcompiler.Boththesepartsareimportantconceptstofullyunderstandtheproblemandndingasolutionforit.Thepracticalpartwasdividedintofoursubparts:ConstructxtUML-models(applicationandserverdomains)toperformbridg-ingbetweenCreateaBridgingMetamodelDevelopmentofArchetypesforcodegenerationGenerationofasystemfromxtUML-modelstoAdabyapplyingthedevel-opedarchetypesontheconstructeddomains.1.3EnvironmentThethesisworkwillbedesignedandimplementedonanexistingapplicationdo-main,amicrowaveoven.Thereasonforchoosingthisdomainasafoundationisbecauseitisapedagogicexample.Everyoneunderstandsthefunctionalityofamicrowaveovenanditiseasytoconstructauserinterfacemodelforit.Thethesisworkwillbediscussedandimplementedwiththesemodelsasfoundation.Themappingstobeimplementedarethosethatareusefulinthisenvironment.Therewillalsobeathirddomainthatwillperformasatestdomain.Themainpurposewiththisdomainistoverifytheimplementedfunctionalitybydemonstratinghoweasyitistoinclude/excludedomainsusingimplicitbridging. 1.4Goal5 1.4GoalThegoalswiththethesisworkarepresentedinthefollowinglist:Fromthesystemdenedin1.3ndandanalyseusefulmappings.Implementfoundmappingsusingimplicitbridging.Generateafullyfunctionalsystemusingimplementedmappings.VerifytheadvantagesofthetechniqueusingtheTest-domain.Withafullyfunctionalsystemmeansthatitwillfullitspurposeandtherewillbenolimitationsbecauseoftheimplicitbridgingimplementation.Theadvan-tagesthatwillbeveriedusingimplicitbridgingaredomainreuseanddomainexchangeability.1.5DelimitationThedelimitationsaredependentonwhichmappingscouldbefoundandimple-mentedinthesystemdenedin1.3.1.6LiteratureThemainsourceforinformationistheInternet.Therehasalsobeenalotofdiscussionwithmysupervisor,whohasgreatknowledgeinthisarea.Othersourcesforinformationarebooksandarticlesdiscussingthistopic,seebibliography.1.7ConventionThroughoutthisthesisdierenttypefacesareusedtodierentiatebetweenthethesisregulartextandtools,code,andsoforth.Generaltextisinromanfont.Termsusedforthersttimeisinitalicfont.Amonospacedfontindicatescode,softwaretools,datatypes,variables,otheridentiersandotherspecialitems.1.8TerminologyTheaudiencesforthisthesisareatleastthosewithanundergraduatedegreeinComputerScience.Thethesisisbasedontheterminologyusedinthebooks[1]and[2].Tocomprehendthisthesisitisenoughtoreadthischapter,butforthosereaderswhowantsdeeperknowledgeinthisareaitisrecommendedthatthebook[1]isreadinadditiontothischapter. 6Introduction 1.8.1CommonTermsConceptsawordsrelatedtothethesiswillbeexplainedhere.OOAObjectOrientedAnalysismodel.OOAofOOATheExecutableandTranslatableUMLmetamodelforOOA.AnalystAnengineerbuildingmodels.ArchitectsAnengineerbuildingthearchitecture.TargetDomainThedomaininwhichtheresultofthemappingisapplied.SourceDomainThedomaininwhichanmappingisinitiated.ClientDomainThedomainthatisdependentonotherdomainstofunctionprop-erly.ServerDomainThedomainoeringservicesrequiredbyotherdomains.1.9ThesisOutlineThestructureofthesisisasfollows:IntroductionThischapterintroducestheobjectiveanddelimitationsforthethe-sis.BackgroundThischapterintroducesandexplainsconceptsandterminologyusedthroughoutthethesis.MicrowaveOvenSystemThischaptergivesanthoroughexplanationoftheMicrowaveOvenSystemanparticipatingdomains.AnalysisforImplicitBridgingThischaptergivesanthoroughanalysisforthewhichmappingstoimplement.Italsodiscussesdesigndecisionsandproblemsforeachofthesemappings.ImplementationofImplicitBridgingThischapterexplanationstheimplemen-tationofthemappings.EvaluationThischaptergivesanevaluationoftheimplementation.Itveriesthefunctionalityandcomparestheimplementationagainstapreviousversion.SummaryThischapterdiscussestheimplementationandconclusionsdrawn.Italsoaddressesfuturework,suchasfurtherdevelopmentintheareaofImplicitBridging.InappendixAtoDthedomainclassdiagramcanbefound. Chapter2BackgroundThischapterintroducesthereadertonotations,conceptsandotherimportantsubjectmattersthatisneededtofullycomprehendthethesis.2.1ExecutableandTranslatableUMLExecutableandTranslatableUML(xtUML)[9]isawell-denedproleofUML,extendedwithpreciseactionsemantics.Thisallowsthedevelopertodenesubjectmatter,domains,insuchadetailthattheycanbeexecuted.AsystemconsistsofseveralexecutableUMLmodels,eachrepresentingasubjectmattersuchastheapplication,auserinterfaceandotherservices.AnxtUML-modelisthesameasanexecutablesystemspecication[12].xtUMLisusedtobuildthesespecicationsgraphically.Thespecicationconsistsofclass,stateandactionmodels.Unliketraditionalspecicationstheseexecutablespeci-cationscanbeexecuted,tested,debuggedandproled.Whenthespecicationfullstherequirementsitcanbetranslatedintocode.Thetranslationprocessistheprocessweremodelelementsaremappedtoim-plementationunits.Themodelscanbetranslatedintodierentimplementationtechnologiesdependingonhowmanyarchitecturesthataresupported.Thetrans-lationprocesswillbediscussedinsection3.4.ExecutableandTranslatableUMLisamongotherthingssuitableforspecicationofcomplexreal-timedistributedandembeddedsystems.7 8Background 2.1.1WhyUseExecutableandTranslatableUML(xtUML)?Thelargestprobleminsoftwaredevelopmentisnotwritingthecode,thatistheeasypart.Thehardpartistodenetheproblemandthisisespeciallytrueoflargeandcomplexsystems.BybuildingthespecicationswithxtUML-models,thesystemspecicationisfullyexecutableconsistingofclass,stateandactionmodelsthatrunlikeaprogram.2.1.2Model-DrivenArchitectureOneoftheadvantageswithxtUMListhepossibilitytodevelopSWandHWplatform-independentspecicationsoftheproblem.ItsupportstheObjectMan-agementGroup(OMG)initiative,Model-DrivenArchitecture(MDA)[3].Thegoalwiththeinitiativeistoallowdeveloperstocomposecompletesystemsfrommodelsandothercomponents.MDAcapturesthesystemfunctionalityinaPlatformIndependentModel(PIM),thedesignandimplementationiscapturedinaPlatformSpecicModel(PSM).ThePIMcanbecompleteandspecicenoughtoenableearlyexecutionandtestoftheapplication,independentofdesignandimplementationspecics.Produc-tiveautomationofaMDAapproachprovidestheopportunityfordramaticdefectreduction,accelerateddevelopment,large-scalereuse,andeasyplatformmigrationofapplications.2.1.3DomainsAdomainisasubjectmatter,aproblemarea[5].Thedomainsareautonomousinthewaythattheycanbeunderstoodwithoutknowledgeaboutotherdomains,buttheyrelyonotherdomainstofunctionproperly.Theseparationofdomainsmakesiteasiertoreuseorexchangedomains.Thereforeitisveryimportanttolimitthecouplingbetweenthem.Thedomainchartingure2.1showsanexampleofvariousdomainsrequiredtobuildasystem.Theapplicationdomaincaptureswhattheapplicationdoes.Theservicedomainscontainfunctionalitybasedontheassumptionsmadebytheapplicationdomain.Forexampleanassumptionfromtheapplicationcouldbethatitassumesthatthereexistssometypeofbuttonpanelforinteraction.Thedesignandfunctionalityofthebuttonpanelisembeddedintheservicedomainimplementingthebuttonpanel.TheArchitecturedomaindenesthetranslationrulesthatwillbeappliedtothemodelsattranslationtime.Adomaincanalsoberealizedascodeanddon'tneedanymodeling.Thisusuallyreferredtoasarealizeddomain.Ingure2.1thefunctionaldomainsdescribewhattheapplicationdomaindoes,withhelpfromtheservicedomains.Thisiscompletelyseparatedfromtheim- 2.1ExecutableandTranslatableUML9 Figure2.1.Domaintypes.plementationanddesigndetailsspeciedbytheimplementationandarchitecturedomains.ThiscreatesaseparateanddistinctapplicationPIM,andsoftwarear-chitecturePSM.ThePSMfullydescribesthetargetplatform,andtheapplicationPIMcompletelydeneswhattheapplicationdoes.Thekey-goalswithdomainsare:Re-usewithoutmodicationReplaceadomainwithanewthatsolvesthesameproblem.2.1.4ExecutableandTranslatableUMLMetamodelAmetamodeldescribesthestructureofamodelandisexpressedusingamod-elinglanguage.ThemetamodelofxtUMLdeneshowthextUML-modelsareconstructedanditisalsousedtocreatethestructureofagenerationdatabase.AgenerationdatabaseistherepositorywherethextUML-modelsarestoredduringthetranslationprocess.WhenimplementingImplicitBridgingthextUML-metamodelhastobeextendedwithbridginginformation.Byextendingthemetamodelvariousbridginginfor-mationcanbestoredwhendeclaringthebridgesandaccessedwhengeneratingbridgingcode. 10Background 2.2BridgingThedenitionofabridge[1]isthatitisalayeringdependencybetweendomains.Onedomainmakesassumptionsandotherdomainstakethoseassumptionsasrequirements. Figure2.2.Aclientandserverdomaindependency.Thebridgecontainsmappingsbetweenelementsinonedomaintoelementsinanotherdomain.Amappingisanamedconnectionbetweentwodomains. Figure2.3.Bridgemappings. 2.2Bridging11 Inthemicrowaveexamplethemicrowaveovenapplicationmakesassumptionsthatauserinterfacewillbepresentedtotheuserinsomeway.Theuserinterfaceservicedomaintakesthoseassumptionsasrequirements.Thedependencyisasymmetricbecausetheserverdomaindoesnotrelyontheapplicationdomaintofunctionproperly.2.2.1ExplicitBridgingWhenabridgecallisinvokedinamodel,anexplicitreferencetoaninterfacedenedbyanotherdomainisperformed.Thisiscalledexplicitbridging.ExplicitBridgingisbotheasytounderstandandeasytouse.Thisisbecausetheyareusedmuchlikeordinaryfunctioncalls.TheproblemwithExplicitBridgingisthatitcausescouplingbetweendomainsandthecouplingincreaseseverytimeanexplicitinterfaceiscalled.Thecouplingmakesitmorediculttoreplaceadomainagainstanotherone.2.2.2ImplicitBridgingImplicitBridging[8][10]techniquewherenoexplicitreferencesfromonemodeltoanothermodelisperformed.Insteaditissolvedbylettingthetranslator/architectureinsertnecessarybridginginformation.Thisconcentratesthecouplinginoneplace,thebridge,anditcaneasilybeconguredandthecouplingbetweenthedomainsisminimized. 12Background Chapter3AutomaticCodeGenerationThischapterwilldiscussdierentapproachestoautomaticcodegenerationandhowthisisperformedinxtUML.Codecanbegeneratedinmanydierentways[11][6]andinthehistoryofsoftwaredevelopmentautomaticcodegeneratorshavebeenaroundsincetheoriginofcompilers[4].Thischapterpresentscommonapproachestogeneratecode.3.1VisualLanguagesInavisuallanguagetheprogramsaredesignedgraphically.Theprogramisde-velopedbyusingpicturesorformsandthesourcecodeisnotaccessibletotheprogrammer.AnexampleofavisuallanguageisLabVIEWbyNationalInstru-ments.Visuallanguagesareveryusefulforprototypingandwhenthegraphicaluserinter-faceisanimportantpartofthesystem.Insystemswithhighsecurityandwherethecodeneedstobemanuallyveriedavisuallanguagecouldnotbeused.3.2VisualProgramingEnvironmentsAvisualprogrammingenvironment(VPE)usesobjectstovisualrepresentthesoftware.ExamplesofvisuallanguagesareVisualBasicandVisualC++.Inthisprogramminglanguagesoftwareisdevelopedandgeneratedusingagraphicaluserinterface.Onlythegraphicaluserinterfaceisgeneratedandthecoreoftheprogramneedstobehandcoded.Thegeneratedsourcecodeisaccessibletotheprogrammerandifneededitcanbeformallyinspected.13 14AutomaticCodeGeneration 3.3DesignModelsModel-basedcodegenerationproducessourcecodeautomaticallyfromgraphicalmodels.Themodel(design)denesthesystembehaviourorarchitecture.Oneadvantageofmodel-baseddevelopmentistoraisethelevelofabstractionforthedevelopers.Thedesign(model)becomestheprogram,andthereisnoneedtomaintainthegeneratedsourcecode.Forobject-orientedsystems,therearethreeapproachestomodel-basedcodegeneration:structural,behavioural,andtransla-tive.Foramorethoroughexplanationsee[2].3.3.1StructuralApproachInthestructuralapproachthemodelsarebasedonanobjectstructure.Thecodegeneratedfromthesesmodelsbuildstheframeworkfortheapplication.Thedy-namicbehaviourmustbemanuallyprogrammedinthetargetlanguages.Thisap-proachistypicallyusedwhenthedesignandcodeisincrementallydevelopedfromtheanalysismodel,thisisreferredtoas"elaborative"development.MethodthatsupportstructuralcodegenerationistheUniedModelingLanguage(UML)[7].Themodelobjectstructureisconstructssuchasclasses,attributes,types,andassociations.Thegeneratedcodevariesbetweentools,sometoolsuseatranslationengineandtemplatesthatspecifymappingstotargetsourcecode.Thetemplates(scripts)translatethemodelstocodestructures,suchasclassheadersorfunctionstubs.Translatorsusuallysupportmarking(coloring)optionssuchaswhichRTOS,objectsornumberofprocessestogeneratecodefor.Inthestructuralapproach,thereisnocodegenerationforobjectbehaviour.Thebehaviourismodeledasstatemachineswithoutexecutablesemantics.Thedy-namicofthesystemmustexplicitlybeprogrammed,thisincludesembeddedcon-structs,suchasinterrupthandling.Thehandcodeisintegratedwiththeassociatedcodestructurethatisgenerated.Structuralcodegenerationdoesnotgenerateacompletesystem,butitprovidesanimplementationframeworkconsistentwiththemodels.Manytoolvendors,forexampleRational,supportstructuralcodegeneration.3.3.2BehaviouralApproachThebehaviouralapproachisbasedonstate-machinesextendedwithactionspec-ications.Insomemethodsthatmodelbehaviourwithstate-machinescode(forexampleC++)canbeaddedtorepresentactionswhenastatetransitionoccurs.Thistechniqueenablestoolstogeneratecodefortheentireapplicationmodel.Oneoftheadvantagesofthistechniqueistheabilitytoexecuteandverifysystembehaviourbasedonthemodelsbeforecodeisgenerated.MethodthatsupportsbehaviouralcodegenerationisUML. 3.3DesignModels15 Inthestatediagrams,usersspecifytheexplicitcodeforhandlingtransitionevents.Thecodeiswritteninthetargetlanguage.Translatorsuseapre-codedexecutioncontrolforthestatemachines,eitheraslibraryroutinesorbuiltintothetranslator.Thisexecutioncontrolimplementsstates,transitions,andcommunicationwithotherstate-machines.Translatorsintegrateevent-handlingcodewiththeexecutioncontrol.Incontrasttothestructuralapproach,behaviouralcodingisperformedduringob-jectmodeling.Inthebehaviouralapproach,programmingisreducedtospecifyingeventhandlersandobjectsthatarehand-coded.Eventhandlerscanimplementembeddedrequirements,forexamplehardwareaccess,interruptsetc.Thedevel-operhasonlyalittlecontrolofthearchitecture.Whenamodeliscompletelydesigneditcanbesimulatedfortestinganddebugging.3.3.3TranslativeApproachThetranslativeapproachisbasedonapplicationandarchitecturemodelsthatareindependentofoneanother.Acompleteapplicationmodelofobjectstructure,be-haviour,andcommunicationiscreatedusingtheObject-OrientedAnalysis(OOA)method,developedbyShlaerandMellor.Likethebehaviouralapproach,develop-erscansimulatesystembehaviorbeforegeneratingcode.Anarchitecturemodelisdevelopedwithatoolthatsupportsthisapproach.Atranslationenginethengeneratescodefortheapplicationaccordingtothemappingrulesinthearchi-tecture.Thetranslativeapproachoerssignicantreusebecausetheapplicationandarchitecturemodelsareindependent.See3.4formoreinformationaboutthetranslationapproach.Thesystemisdenedusingasetofdomains.Themodelhasobjectmodels,statemodelsforeachobject,andactionspecicationsforeachstate.Actionspecica-tionsarewritteninanactionlanguage.Theactionlanguageisspecicforthetoolvendor.Simulationisperformedbyinterpretingtheactionspecications.Thisallowstheapplicationmodeltobeveriedbeforecodegeneration.Thereisalotofworkinbuildinganarchitecturemodel.Translationmappingsarewritteninascriptinglanguage.Thesemappingshavetypicalprogrammingconstructs:literalstringoutput,substitutionofspecicmodelobjectsforvariablesofthetranslationrules,anditerationandselectionoftranslationrules.Thetranslativeapproachproducesanapplicationallatonce,incontrasttothestructuralapproachwheretheapplicationmodeliselaboratedintodesignandcode.Thedevelopmentoftheapplicationmodel,whichisaPIM,andthear-chitecturemodel,whichisaPSMcouldbeindependentlyofoneanother.Whentheapplicationandarchitecturemodelsareputtogether,translationgeneratesanapplication.Whiletheapplicationmodelcanbeveriedbysimulation,thearchi-tecturemodelisveriedmainlybysuccessfultranslationsandifpossiblebycodeinspection.Theirindependenceallowsapplicationmodelstobereusedwithdif- 16AutomaticCodeGeneration ferentarchitecturesandarchitecturestotranslateotherapplicationmodels.Withthetranslativeapproach,theapplicationmodel,insteadofsourcecode,becomestheprincipalsoftwareartefact. 3.4CodeTranslation17 3.4CodeTranslationThetranslationprocessistheprocessweremodelelementsaremappedtoimple-mentationunits.Thetranslationprocesscanbemanual,automatedoramixtureofboth.Thissectionwilldiscusstheautomatedapproach,translation.Formoreinformationaboutcodegenerationsee3.ThetranslationprocessgeneratescodefromthextUML-modelwithoutalteringthemodel.Forfullautomationofthetranslationamodelcompilerisneeded.Theseparationofthemodelsandtheimplementationreducestheriskofloosingeverythingifforinstancetheimplementationisbad.Theimplementationcouldbethrownoutandanewdesigncouldbestartedwiththesamemodels.3.4.1CodeGenerationCodegenerationisthetechniquewherecodeisgeneratedfromtheOOA-model,basedonanautomaticrule-basedtranslationscheme.Themajoradvantageswithcodegenerationare:SeparationofthemodelingandtheimplementationConsistencybetweenmodel,codeanddocumentationCodeconstructsarethesamesystemwideAbilitytoapplycodeconstructssystemwidePossibilityforplatformindependentdevelopment.Asmentionedbeforethetranslationprocessleavesthemodelsintactandthishasalotofadvantages.Themodelscanbeseparatelymaintainedandwhenchangeshasbeenmadetoamodel,thesystemisretranslated.Ifthereisanoptimizationchangeinanalgorithmthemodelcompilerwillbeupdatedandwhenthesystemisretranslatedthebenetsoftheoptimizationwillbeusedinthewholesystem.Model-basedmaintenanceeitheraddressesto:1.Applicationbehaviourissues2.Performance-basedissues.Forapplicationbehaviourissuestheapplicationmodelismodiedandthecodeisregenerated.Forperformance-basedissuesthearchitecturemodelismodiedandthecodeisregenerated.Oneimportantconclusionisthatgeneratedcodeshallneverbemodied. 18AutomaticCodeGeneration 3.4.2ModelCompilersAmodelcompilertakesoneormorextUML-modelsandtranslatesthemintoarunningsystem.Howthetranslationisperformeddependsonthetranslationpat-ternembeddedinsidethemodelcompileranddecisionsaboutthetargethardwareandsoftwareenvironment.Therearemanydierentmodelcompilersdependingonthesystemarchitecture.EachmodelcompilercancompileanyxtUML-modelintoanimplementation.Themaincomponentsofamodelcompilerare:MechanismsArchetypesColors.Mechanismarelibrarycomponentsthatprovidesthemodelcompilerwithimple-mentationdetailsfortheelementsinxtUML.Mechanismsprovidetheexecutionenginewitheventhandling,executioncontrolandmore.Archetypesisacombinationofcodepatternsandtranslationrules.Thearchetypesproducetheoutputofthemodelcompileranditcanbeinanytraditionalprogram-minglanguage(orinassembly).ThearchetypeshasaccesstothextUML-modelsthatarestoredinthegenerationdatabase.Coloringistheprocesswheredesignspecicdecisionsareaddedtothemodels.ItcouldbespecifyingifsomecodewillbeexecutedonaspecicCPUorspecifyingmaximumnumberofinstancesforaclass.Thecoloringisappliedtothemodelsduringtranslationanditdoesnotmodifythemodels.3.4.3OpenTranslationOpentranslationallowsarchitectstoadjustthetranslationprocess,thearchitectisinfullcontrolofhowtheresultingcodeperformsandlookslike.Thisisimpor-tantforensuringthatgeneratedcodeiscustomizedtothehardwareandsoftwareenvironmentitrunin.Thisisespeciallyimportantforembeddedreal-timesystems. 3.4CodeTranslation19 3.4.4TranslationProcessThetranslationprocessisdescribedingure3.1.TheBridgePointModelBuilderistheapplicationwherethextUML-modelsaredeveloped[13].WhenamodelisnisheditisexportedfromthemodelbuildertoaSQL-le.WhenthecodegenerationbeginsitcreatesagenerationdatabasewiththestructuredenedintheExecutableandTranslatableUMLmetamodelandOODArchitecture.Theexportedmodelsarereadintothisdatabaseandcolored,designspecicdecisionsareaddedtothemodels,beforethecodeisgenerated.Theimplictbridgingimplementationwillbeintegratedintothisprocess. Figure3.1.Translationprocess. 20AutomaticCodeGeneration Chapter4MicrowaveOvenSystemInthischaptertheMicrowaveOvenSystem(MOS)isdescribed.4.1PurposeTheMOSwillbeusedasanexampleforhowimplicitbridgingcouldbeapplied.Thesystemisdesignedaroundthreedomains:AMicrowaveOvenapplicationdomain(MO)AnUserInterfaceservicedomain(UI)AGraphicalUserInterfaceservicedomain(GUI).TheMOandUIdomainarextUML-modelsandtheGUIisarealizeddomain.TheMOdomaincontainsthefunctionalityofamicrowaveoven.TheUIdomaincontainsbuttons,lampsandotheruserinterfacecomponents.TheMOandUIareseparatedbecausetheMOdomaindoesnotneedtoknowhowtheusersinteractionwiththemicrowaveovenisimplemented.Insteadofbuttonstherecouldbeavoicepanelforinteractingwiththemicrowaveoven.ImplicitbridgingwillbeappliedbetweentheMOandUIdomains.TheGUIdomainwillpresentaGUIwhereinteractionswiththesystemispossible.Therewillalsobeafourthdomain,atestdomain,anditwillbeusedwithimplicitbridgingagainstboththeUIandMOdomains.Thepurposeofthisdomainistoverifytheimplicitbridgingimplementationbyshowingifdomainseasilycanbeaddedorremovedinthesystem,withoutchangingthextUML-models.Itwillalsoshowthatwhendomainsareindependentofeachother,theycanbereusable.21 22MicrowaveOvenSystem 4.2FunctionalityWhenstartingthemicrowavesystem,agraphicaluserinterfaceispresentedtotheuser.Alltheparticipatingdomainsareinitializedandthesystemwaitsforsysteminteraction.TheGUIletstheusersetthecookingtimeopen/closethedoorstart/stopacookingpresentcurrentstatusFigure4.1explainsthedierentpartsoftheGUI. Figure4.1.Thegraphicaluserinterface. 4.2Functionality23 4.2.1DomainsThedomainchartdescribingthedomainsinthesystemcanbeviewedinappendixE.4.2.2MicrowaveOvenThemicrowaveovendomaincontainsthefunctionalityofamicrowaveoven.Ithasanoven,abeeper,adoorandothercommonmicrowaveovenobjects.TheclassdiagramforthemicrowaveovenmodelcanbeviewedinappendixB.ThemicrowaveovenxtUML-modelusedinthethesisworkwasdeliveredwithBridgePointModelBuilder,developedbyProjectTechnology1.4.2.3UserInterfaceTheuserinterfacedomaincontainsfunctionalityforcomponentslikebuttons,lampsandsoforth.ItisseparatedfromtheMOdomainbecauseitcontainsfunctionalitythatisofnousefortheMOdomain.ItwillbecloselycoupledtotheGUIdomain.TheclassdiagramfortheuserinterfacemodelcanbeviewedinappendixC.4.2.4TestThepurposeofthetestdomainistoverifythefunctionalityoftheimplicitbridgingimplementation.ItwillbeusedtoshowthatthedomainsareindependentandreusablebymappingboththeUIandtheMOdomainsontoit.Itwillalsobeusedtoverifythatitissimpletoadd/removedomainsinthesystemusingtheImplicitBridgingtechnique.4.2.5GraphicalUserInterfaceThegraphicaluserinterfacedomainisrealizedinTcl/Tkandhastheappearanceofamicrowaveoven.Itwillbeusedbytheusertooperatethemicrowaveoven.Figures4.2,4.3and4.4showsthemicrowaveovenGUIindierentstates. 1www.projtech.com 24MicrowaveOvenSystem Figure4.2.Thedoorisopen. Figure4.3.Themicrowaveoveniscooking. 4.2Functionality25 Figure4.4.Themicrowaveovenisidle. 26MicrowaveOvenSystem Chapter5AnalysisforImplicitBridgingThischaptergivesananalysisofthesystemandwhichmappingstoimplement.Italsodiscussesdesigndecisionsforeachmapping.5.1HowtheimplementedmappingswerefoundWhichmappingstoimplementweredecidedbyanalyzingthesystem,MOS,weretheywillbeused.OneofthegoalswiththesystemistobeabletocompilethemodelsMOandUIintoafunctionalsystemwithoutusinganyexplicitbridgingbetweenthem.BetweentherealizedGUIdomainandUImodeltherewillbeexplicitbridging.MainlybecausethereisnorequirementforimplementingimplicitbridgingbetweenaxtUML-modelandarealizeddomain.ThesystemisonlyusefuliftheusercaninteractwiththesystemandthisimpliesthattheUIandMOdomainsmustinteractwitheachother.BecausethereisnoexplicitcouplingbetweenthemodelsUIandMO,allinteractionsmustbeimplicitlymapped.ThemicrowavesystemGUImustbeabletosetthecookingtime,start/stopacookingsession,open/closethemicrowavedoor,presentthecurrentstatusofanarbitraryobjectintheMOdomain.27 28AnalysisforImplicitBridging WhenabuttonintheGUIisclickeditwillgenerateaneventintheUIdomain.ThiseventmustbemappedtoanelementintheMOdomain.ThemostintuitiveistomapthebuttonclickedeventtoaneventintheMOdomain,acounterpartevent.ThereforetheCounterpartEventMappingwillbeimplemented.Theeventsthataremappedtogetherarestatemodeleventsandtheybelongtoanobjectineachdomain.Thismeansthatitmustbepossibletondaknowninstanceofanobjectinaremotedomain.ThereforetheCounterpartObjectMappingwillbeimplemented.ThecookingtimethatispresentedintheGUIshouldalwayshavethesametimeasthetimerintheovenobjectintheMOdomain.ThereforetheCounterpartAttributeMappingwillbeimplemented.ThestatusofanyarbitraryobjectintheMOdomainwillbepresentedintheGUIusingoneofthelamps.Thestatusisthecurrentstateofanobjectanditchangeswhenevertheobjectchangesstate.Thisresultsintwomappings,therstiswhenanobjectstateismappedtoanelementintheotherdomain.InthiscaseitwillbemappedtoanattributevalueandthisistheStateToAttributeValueMapping.Thesecondmappingiswhenanobjectexitsastate,thenasbeforeavalueintheotherdomainisset.ThisistheNewStateTransitionToAttributeValueMappingandboththesewillbeimplemented. 5.2CounterpartObjectMapping29 5.2CounterpartObjectMapping5.2.1DescriptionACounterpartObjectMapping(COM)betweentwoobjectsmeansthatifanyofthethesetwoobjectsiscreatedsoisalsothecounterpartobject.Ifanyofthesestwoobjectsisdeletedsoisalsothecounterpartobject.Thismappingiscommutative,thatisvalidinbothdirections. Figure5.1.TheCounterpartObjectMapping.Figure5.1showsasequencediagramwhereaCOMisinvokedwhenaninstanceoftheDoorclassiscreated.TheCOMinvokesthecreatefunctioninthecounterpartobjectandaninstanceofthecounterpartisalsocreated.ThegurealsoshowsthattheCOMisinvokedwhenanobjectisdeleted.5.2.2DesignDecisionsWhendesigningthefunctionalityoftheCOMfollowingthingshadtobetakenintoconsideration:1.Avoidcyclicbehaviourwhencreating/deletingtheobjects.2.Maponeobjectagainstmorethanoneobject.3.Mappingsequencelargerthantwo.4.Mappingagainstmorethanonedomain.5.Thepossibilitytomakethemappingunidirectional,non-commutative.Therstproblemappearswhenoneobjectiscreatedanditinitsconstructorcallstheconstructorinthecounterpartobject.Becausethemappingiscommutativethe 30AnalysisforImplicitBridging calledobjectwillhavesimilarcodeinitsconstructorthatwillcallitscounterpartobject,segure5.2,andsoforth.Theproblemissimilarwhenanobjectisdeleted. Figure5.2.ACOMbetweentwoobjects.ThesecondproblemisifthereshouldbepossibletohaveCOMsfromoneob-jecttomorethanoneobject.ThisaddsalittlemorecomplexitytothepreviousproblemsinceanobjectmustknowfromwhichCOMthecreationwasinitiated.Somehowthecounterpartmustbeabletodistinguishbetweenthedierentcoun-terpartobjectssothatthecounterpartobjectthatinitiatedthecreationwontbecreatedagain. Figure5.3.ACOMbetweenseveralobjects.Thegure5.3showsthattheDoorobjecthaveCOMtoboththeLampandButtonobject.ItshouldbepossiblefortheLamptopresentthecurrentstateoftheDoor.ItshouldalsobepossibletoopenandclosetheDoorthroughaButton.ThereforeitisimportantthatthereisapossibilitytodeneCOMfromoneobjecttooneormoreobjects.ThethirdproblemisifthereshouldbealimitoranarbitrarylengthonaCOMsequence.Ingure5.4aCOMsequenceoflengthtwoappearsbecauseoftheCOMbetweenDoorandOpen ButtonandtheCOMbetweenOpen ButtonandTest Object.ThecomplexityandriskforcyclicobjectcreationincreaseswhentheCOMse-quenceincreases.Theproblemisshowingure5.5,whereboththeDoorandOpen ButtonobjectsarecounterparttotheTestobject. 5.2CounterpartObjectMapping31 Figure5.4.ACOMsequence. Figure5.5.AcyclicCOMsequence.Thediscussioninsection4.2.4aboutthepurposeoftheTestdomainandthatitshouldbepossibletoconnectaTest ObjecttooneoftheButtonobjectsandsimulateabuttonclickedeventtochangethestateoftheOvenobject.Thisfunc-tionalityimpliesthataCOMsequencelargerthanonemustbeallowed.TosimplifytheCOM,anobjectcouldbelimitedtoonlybeabletodeneCOMstooneotherdomain.ThislimitationmakesthepreviousdiscussedfunctionalityimpossibleandthereforeitshouldbepossibletoperformCOMbetweentwoormoredomains.InsomecasesitwouldbeusefultobeabletoperformunidirectionalCOM.ForexamplewhenperformingaCOMbetweenasourceobjectinsomearbitrarydo-mainagainstatargetobjectinsometestdomain.Whenthesourceobjectinthearbitrarydomainiscreateditautomaticallycreates,viatheCOM,aninstanceofantestobjectinthetestdomain.Thetestobjecttheninitializesatestsequenceonthecounterpartobjectandwhenthetestsequenceisnishedthetestobjectisdeleted.Theunidirectionalmappingensuresthatthesourceobjectnotisdeleted.IntheMOSthereisnorequirementforunidirectionalCOMfunctionalityandthereforethisfunctionalitywillonlybeimplementedifthetimeallowsitattheendoftheproject. 32AnalysisforImplicitBridging 5.3CounterpartEventMapping5.3.1DescriptionACounterpartEventMapping(CEM)iswhenagenerationofaneventinasourcedomainautomaticallycausesagenerationofaneventinatargetdomain.Figure5.6showsanexamplewhenaCEMcouldbeused. Figure5.6.PossibleCounterpartEventMapping.ThegureshowspartsofthestatediagramsfortheDoorobjectintheMOdomainandtheOpen ButtonintheUIdomain.HereaCEMbetweentheOpen ButtoneventOpen Button ClickedandtheDooreventreleasecouldbedened.EverytimetheOpen Button ClickedisgenerateditautomaticallygeneratesthereleaseeventintheDoorobject. 5.3CounterpartEventMapping33 5.3.2DesignDecisionsWhendesigningCEMfollowingthingshadtobetakenintoconsideration:1.Avoidcycliceventgeneration.2.Maponeeventtomorethanoneevent.3.Mappingsequencelargerthantwo.4.Mappingagainstoneormoreotherdomains.5.Thepossibilitytomakethemappingunidirectional,non-commutative.6.Thepossibilitytohaveeventparameters.ThedesignproblemsareverysimilartothoseintheCOM.Therstproblemistoavoidcycliceventgeneration.Theproblemoccursifaneventgeneratesacounterparteventandthecounterpartcausesaregenerationofthepreviousevent.Figure5.7showstheproblemwhentheOpen Button Clickedisgenerated.Itgeneratesitscounterparteventandsoforth. Figure5.7.Cycliceventgeneration.Thereshouldbepossibletomaponeeventtomorethatonecounterpartevents.IntheMOStheOveneventStart Cookingismappedtotwocounterpartevents,seegure5.8 34AnalysisforImplicitBridging Figure5.8.ACEMwithmorethanonecounterpartevents. Figure5.9.ACEMsequencewithmorethantwocounterpartevents.Theremustalsobepossibletohaveamappingsequencelargerthattwo.IntheMOSthereexistsequenceslargerthantwo,seegur5.9.Thereshouldnotbealimitationofthenumberofdomainsthatcouldbemappedbetween. 5.3CounterpartEventMapping35 Itshouldalsobepossibletodeneunidirectionalmappings.Intheexamplede-scribedinsection5.3.1whencreatingCEMbetweentheOpen Button Clickedeventandthereleaseeventitwouldbepreferabletohaveanundirectedmap-ping.Thisisbecauseitwillnevergenerateareleaseeventiftherehasnotbeenanopenbuttoneventinitiatingit.Itshouldalsobepossibletohaveeventparameters.ThemappedeventStart B-utton Clickedhasaperiodtimeasparameter. 36AnalysisforImplicitBridging 5.4CounterpartAttributeMapping5.4.1DescriptionACounterpartAttributeMapping(CAM)iswhentwoattributesaremappedto-gether.Whenreadingthesourceattributethetargetattributeisreturned.Whenwritingtothesourceattributethetargetismodied.Thismappingisnotcom-mutativebecausethevalueneedstobestoredinoneoftheattributes.Thegure5.10showsanexampleofaCAM. Figure5.10.ApossibleCounterpartAttributeMapping.Ingure5.10theremaining timeattributeisthesourceattributeandtheremainin-g cooking timeisthetargetattribute.5.4.2DesignDecisionsFollowingthingshadtobetakenintoconsiderationwhendesigningtheCAM:1.betweenwhichattributetypescouldmappingbeapplied,2.shouldtherebeapossibilitytospecifyreadandwritepropertiesand3.betweenwhichdatatypescouldamappingbedened.Thereexisttwoattributetypes,derivedandstored.Thederivedattributereturnthevalueofafunctionanditisnotwritable.Thestoredattributeisaregularattribute,whichmeansthatitcouldbereadandwrittento. 5.4CounterpartAttributeMapping37 Figure5.11showspossibleattributemappings.Themostimportantisthatthedo-mainsshouldnottakeanythingregardingotherdomainsintoconsideration.There-forethemappingfromastoredattributetoaderivedattributeshouldbeforbidden.Alltheotherattributetypemappingsarevalid. Figure5.11.Possibleattributetypemappings.TheattributetypemappingsthatwillbeperformedintheMOSarederivedtoderivedandstoredtostored.Therstofthetwomappingsmappingisbetweenthederivedattributes,CurrentTimerValueintheUITimerobjectandCurrentOvenTimerValueintheOvenobject.ThesecondmappingisbetweenthestoredattributesTimeintheStartButtonobjectintheUIdomainandtheremainingcookingtimeintheOven.Thestoredtostoredattributemappingistheonlywherewritingtothetargetattributeispossible.Thismappingwillnotbeusedinthecurrentimplementation;thereforeonlyreadpropertieswillnotbeimplemented.ThethirddecisionistodecidebetweenwhichdatatypesaCAMcouldbeper-formed.Theproblemoccurswhenthesourceandtargetattributeisnotofthesametypeandsomeformofconversionisneeded.Theconversioncouldbeper-formedbyasimpletypeconversionorusingamorecomplexconvertingfunction.IntheMOStheattributesthataremappedtogetherareofthesametype.Sim-pletypeconversionwillbeimplementedandgure5.12showbetweenwhichdatatypesmappingisallowed.Theattributemappingbetweenattributesoftheenumerationdatatypewillnotbeimplemented,mainlybecausethereisnoneedforitintheMOSsystem.Thesecondreasonisthatitisacomplexanddicultmappingtoimplement.ForexamplehowshouldamappingbetweenanenumerationattributeObject State,withthevaluesOn,O,toanenumerationattributeButton State,withthevaluesState 1,State 2,State 3,looklike.ShouldState 1bemappedontoOnandtheotherstatevaluestoOorshouldonlyoneoftheotherstatesbemappedtothe 38AnalysisforImplicitBridging Figure5.12.Tabelofalloweddatatypestobemapped.Ovalue.Thesearesomeofthethingsthatmustbetakenintoconsiderationwhenimplementingattributemappingfortheenumerationdatatype.Itissimilartotheproblemwhenmappingbetweendierentdatatypesandsomekindofconversionfunctionisneeded. 5.5StateToAttributeValueMapping39 5.5StateToAttributeValueMapping5.5.1DescriptionAStateToAttributeValueMapping(STAVM)iswhenanobjectstateismappedtoanattributevalue.Whentheobjectentersthemappedstateitcausesthemappedattributevaluetobemodied.Thevalueisaconstantgivenatthedeclarationofthemapping. Figure5.13.AStateToAttributeValueMapping.Figure5.13showshowaSTAVMcouldbeused.TheopenstateismappedontothevariableLamp Status.5.5.2DesignDecisionsThemaindecisionforthismappingweredecidewhichdatatypestheattributevaluecouldhave.IntheMOSthemappingisusedtomaptheovenstatetooneofthelampsintheUIdomain.Thisissolvedbyusingastringvariable. 40AnalysisforImplicitBridging 5.6NewStateTransitionToAttributeValueMap-ping5.6.1DescriptionANewStateTransitionToAttributeValueMapping(NSTTAVM)iswhentheexitfromanobjectstatewithaspecictransitionismappedtoanattributeinanotherdomain.Whentheobjectexitsthemappedstatewithaspeciedtransitionincausesthemappedattributevaluetobemodied. Figure5.14.TwoNSTTAVMstothesameattribute.Figure5.14showsanexamplewheretheNSTTAVMcouldbeapplied.Thismap-pingwouldmapallexitstatesfromtheCookingstatetotheLamp StatusattributeintheRight Lampobject.AnimportantnoticeisthatthiscouldalsobesolvedwiththeSTAVM,butonlyifbothmappingsdenesthesameattributevalue.Insteadofmappingeachtransitionthestatewherethetransitionleadstoismapped.Toclarifythedierencebetweenthesetwomappingtypes,gure5.15illustratesanexamplewhereNSTTAVMscouldbeusedtodeneonemappingforeachtransitiontotheerrorstate.Whendoingsotheattributevaluebesettodierentvaluesdependingonfromwhichstatethenewstatetransitionwasactivated.ThiscouldnotbedenedusingtheSTAVMbecauseitcouldonlymaponeattributevaluefortheerrorstate. 5.6NewStateTransitionToAttributeValueMapping41 Figure5.15.TwoNSTTAVMstothesameattribute.5.6.2DesignDecisionsThedesigndecisionsthatweremadeforthismappingwaswhichdatatypestheattributecouldhave.IntheMOSthemappingisinonecaseusedtosetthecolouroftheRight LampwhentheOvenexitsthecookingstate.Thisissolvedbyusingastringvariable. 42AnalysisforImplicitBridging Chapter6ImplementationofImplicitBridgingInthischaptertheimplementationdetailswillbepresented.6.1MicrowaveOvenSystem6.1.1MicrowaveOvenThereweresomechangesthathadtobedonetoadaptthisdomaintotheim-plementation.TheremainingcookingtimewillbepresentedintheGUIanditwillbesetusinganCAMbetweenanattributeintheUIdomainanattributeintheMOdomain.Theattributeremaining cooking timeintheOvenclassholdstheremaingtimewhentheovenstateisnotintheCookingstate.ThereforetheCurrent Oven Timer Valueattributehadtobeaddedandthismappedattributereturnstheremainingcookingtimewhenitisread.Theremaining cooking timeattributewillbeusedimplicitlytosetthecookingtimeusingaCAM.6.1.2UserInterfaceTheUIdomainisaservicedomainanditiscloselycoupledtotheGUIdomain.ThemainfunctionalityistoactasamiddledomainforinteractionbetweentheGUIandMOdomain.ItwillactasaneventhandlerwhenabuttonintheGUIisclickedandimplicitlygeneratecounterparteventsintheMOdomain.ItwillupdatetheGUItimerbycontinuallypollingtheUI TimerandimplicitlyreceiveavaluefromacounterpartattributeintheMOdomain.TheLampclassholdsastringvaluerepresentingthestatusontheobjectthatismappedontoit.Thestatusattributeinthiscasewillbeusedtosetthecolorofthelamps.43 44ImplementationofImplicitBridging AlllogicalUIcomponentshasanhandlerclassthatforexamplewaitsforancre-ationoftheobjecttohandle,handlestheobjectbypollingavalueorstateandupdatingtheGUIdependingonthevalues.6.1.3TestTheTestdomaindenesatestsequencethatgenerateseventstoanumberoftestobjects.Itwillpresentaserverinterfacethatmakesitpossibletomapobjectsandbelongingeventstothesetestobjects.Whenthetestsequenceisinitiateditwillforeachtestobjectgeneratethecor-respondingeventandthiswillautomaticallycausethecounterparteventtobegenerated.ItcanbeusedtogetherwithanydomaininthemicrowavesystemandfortestpurposesitwillbeusedtogetherwithboththeUIandtheMOdomains.IntherstdomaincongurationtheUIdomainwillbemappedontointotheTestdomainandalldomainsinthemicrowavesystemwillparticipate.InthesecondcongurationtheUIandGUIdomainwillberemovedandtheMOdomainwillbemappedontotheTestdomain.ThiswillshowthattheMOdomainisnotdependentontheotherdomainstoexecuteandwhenusingimplicitbridgingthedomainsarereusable.ItwillalsoshowthereisnoneedtomakeanychangesinthexUML-modelswhenremoving/switchingdomainsusingimplicitbridging.Allfunctionalityisdenedinthebridges.Thetestsequenceispresentedingure6.1.ThegureisanextractionofanstateinthestatemodelfortheTest Sequenceobject.ThetestsequencefortheUIdomain:1.Testevent1willgenerateaclosebuttoneventtotheCloseButtonobject.2.Testevent2willgenerateastartcookingeventtotheStartButtonobject.3.Testevent3willgenerateanopenbuttoneventtotheOpenButtonobject.4.Testevent4willgenerateaclosebuttoneventtotheCloseButtonobject.ThetestsequencefortheMOdomain:1.Testevent1willgenerateaclosebuttoneventtotheDoorobject.2.Testevent2willgenerateastartcookingeventtotheOvenobject.3.Testevent3willgenerateanopenbuttoneventtotheDoorobject.4.Testevent4willgenerateaclosebuttoneventtotheDoorobject. 6.1MicrowaveOvenSystem45 Figure6.1.Thetestsequence.6.1.4GraphicalUserInterfaceTheGUIdoesnotshoweverythingbydefault.Whatisshowndependsonthebridgingconguration.Forexample,alampisonlyshowniftheLampobjectintheUIdomainhavebeenmappedtoacounterpartobject.Thecolourofthemappingisalsoconguredinthebridge.Thesameappliesforthebuttons. 46ImplementationofImplicitBridging 6.2HowtheMappingswereImplementedEachmappingmustbedenedbyextendingtheOOAofOOA,theextensionisusedtostorebridginginformation.TheextensionisplacedinanmetamodelnamedtheBridgingMetamodel,seeappendixA.WhenthesystemistranslatedtocodetheBridgingMetamodelistranslatedintoSQLstatementsandthesestatementsareusedtostoreandaccessbridginginformationduringthetranslation.Figure6.2showsanexampleonhowanextensioncouldbedened.InthisexampletheState To Attribute Value MappingisthebridgemodeldeningabridgebetweentheOOAelementsAttributeandStateModelState.TheBridgingMetamodelwasconstructedusinghalftables.Ahalftableisatableconstructedwithtwohalves,onehalfspecifyingelementsintheclientdomainandtheotherhalfspecifyingelementsintheserverdomain.TheelementsarethejoinpointsineachdomainandconsistofonlyOOAofOOAelements.Figure6.3showsthehalftablefortheSTAVMdenedinthebridgemodel6.2. Figure6.2.AbridgemodelfortheSTAVM. 6.2HowtheMappingswereImplemented47 Figure6.3.AhalftablefortheSTAVM.Whenimplementingamappingtherststepistoimplementitinthesourcecode.Whenitworksasthespecicationitcanbetransformedintoanarchetypethatgeneratestheimplementedcode. 48ImplementationofImplicitBridging 6.3MappingImplementation6.3.1CounterpartObjectMappingThismappingisusedfornavigationpurposebetweendomainsandallothermap-pingstobeimplementedwilldependonit,seeappendixA.ThefollowingfunctioninvocationcreatesaCOMbetweentheDoorandLeft Lampobjects.Thisfunctionisimplementedinthearchitectureandisinvokedwhendeningthebridge,seesection6.4..invokeCounterpart_Object_Mapping(Impl_Bridge_Ref,``Door_To_Left_Lamp_Mapping'',Microwave_Oven,Door,User_Interface,Left_Lamp)Themappingimplementationconsistsmainlyofplacingcodeinthoseplaceswhereobjectsarecreatedanddeleted.ThefollowingcodeshowsthegeneratedCreatefunctionintheDoorobject.ThebridgingcodeconsistsofafunctioncalltothecreatefunctionintheLeft Lampcounterpartobjectandrelationshipcreationfornavigationpurposes.withUI.Left_Lamp;...packagebodyMO.Doorsi...procedureCreate(Instance:outInstances.Identification)is...--BridgingcodeLeft_Lamp_Id:UI.Left_Lamp.Instances.Identification;--begin...--CounterpartObjectCreationUI.Left_Lamp.Create_Counterpart_To_Door(Left_Lamp_Id);MO_To_UI_Bridge.Door_To_Left_Lamp_Mapping.Relate(Instance,Left_Lamp_Id);MO_To_UI_Bridge.Left_Lamp_To_Door_Mapping.Relate(Left_Lamp_Id,Instance);--endCreate;...endMO.Door;Fromtheanalysisfollowingproblemshadtobetakenintoconsideration.1.Avoidcyclicbehaviourwhencreating/deletingtheobjects.2.Maponeobjectagainstmorethanoneobject.3.Mappingsequencelargerthantwo.4.Mappingagainstmorethanonedomain.5.Thepossibilitytomakethemappingunidirectional,non-commutative. 6.3MappingImplementation49 Therstdesignproblemissolvedbyaddinganewcreatefunctionforeachcoun-terpartmapping.Thisfunctionwillnotincludefunctioncallstothecounterpartobjectthatcallsit.ThecodeaboveshowstheCreatefunctionintheDoorobject.WhencreatinganinstanceofthecounterpartobjectLeft Lamp,thenewfunctionCreate Counterpart To Dooriscalled.ThisfunctiondoesnotincludefunctioncallsbacktotheDoorobject.ThesolutiontothesecondproblemistohavefunctioncallstoallCOMsinthecreatefunction.ThefollowingcodeshowsthattheDoornowiscounterparttoLeft Lamp,Open ButtonandClose Button.withUI.Left_Lamp;withUI.Open_Button;withUI.Close_Button;...packagebodyMO.Dooris...procedureCreate(Instance:outInstances.Identification)is...--BridgingcodeLeft_Lamp_Id:UI.Left_Lamp.Instances.Identification;Open_Button_Id:UI.Open_Button.Instances.Identification;Close_Button_Id:UI.Close_Button.Instances.Identification;--begin...--CounterpartObjectCreationUI.Left_Lamp.Create_Counterpart_To_Door(Left_Lamp_Id);MO_To_UI_Bridge.Door_To_Left_Lamp_Mapping.Relate(Instance,Left_Lamp_Id);MO_To_UI_Bridge.Left_Lamp_To_Door_Mapping.Relate(Left_Lamp_Id,Instance);UI.Open_Button.Create_Counterpart_To_Door(Open_Button_Id);MO_To_UI_Bridge.Door_To_Open_Button_Mapping.Relate(Instance,Open_Button_Id);MO_To_UI_Bridge.Open_Button_To_Door_Mapping.Relate(Open_Button_Id,Instance);UI.Close_Button.Create_Counterpart_To_Door(Close_Button_Id);MO_To_UI_Bridge.Door_To_Close_Button_Mapping.Relate(Instance,Close_Button_Id);MO_To_UI_Bridge.Close_Button_To_Door_Mapping.Relate(Close_Button_Id,Instance);--endCreate;...endMO:Door;Tomapagainstmorethanonedomainispossible.ThefollowingcodeshowstheCreatefunctioninStart ButtonandthatitiscounterpartwithOvenintheMOdomainandtheTest Object 2intheTestdomain.withTest.Test_Object_2;withMO.Oven;...packageUI.Start_Buttonis...procedureCreate(Instance:outInstances.Identification)is...--Bridgingcode 50ImplementationofImplicitBridging Oven_Id:MO.Oven.Instances.Identification;Test_Object_2_Id:Test.Test_Object_2.Instances.Identification;--begin...--CounterpartObjectCreationMO.Oven.Create_Counterpart_To_Start_Button(Oven_Id);MO_To_UI_Bridge.Start_Button_To_Oven_Mapping.Relate(Instance,Oven_Id);MO_To_UI_Bridge.Oven_To_Start_Button_Mapping.Relate(Oven_Id,Instance);Test.Test_Object_2.Create_Counterpart_To_Start_Button(Test_Object_2_Id);UI_To_Test_Bridge.Start_Button_To_Test_Object_2_Mapping.Relate(Instance,Test_Object_2_Id);UI_To_Test_Bridge.Test_Object_2_To_Start_Button_Mapping.Relate(Test_Object_2_Id,Instance);--endCreate;...endUI.Start_ButtonisThereisnolimitintheimplementationonthesizeofaCOMsequence.InthecodepresentedaboveasequencewilloccurifforinstancetheOveniscreatedrst.ThecreatefunctioninStart ButtonwillbecalledfromthecreatefunctionintheOvenobject.ThecreatefunctionintheStart ButtonobjectwillcallthecreatefunctionfortheTest Object 2.ThesolutiontoavoidcycliccreationandallowmorethanoneCOMinasequenceistoforeachcounterpartobjectdeneaspecialcreatesfunction.ThisfunctionwillonlybecalledbythecounterpartobjectitisdenedforandiftheobjecthasmorethanoneCOMdenedthesewillbecalledfromthisfunction.ThefollowingcodeshowstheCreate Counterpart To OvenfunctiondenedintheStart Buttonobject.ThisfunctionwillbecalledfromtheCreatefunctionintheOvenobject.ItwillinturncalltheCreate Counterpart To Start ButtoninTest Object 2.withTest.Test_Object_2;withMO.Oven;...packageUI.Start_Buttonis...procedureCreate_Counterpart_To_Oven(Instance:outInstances.Identification)is...--BridgingcodeTest_Object_2_Id:Test.Test_Object_2.Instances.Identification;--begin...--CounterpartObjectCreationTest.Test_Object_2.Create_Counterpart_To_Start_Button(Test_Object_2_Id);UI_To_Test_Bridge.Start_Button_To_Test_Object_2_Mapping.Relate(Instance,Test_Object_2_Id);UI_To_Test_Bridge.Test_Object_2_To_Start_Button_Mapping.Relate(Test_Object_2_Id,Instance);-- 6.3MappingImplementation51 endCreate_Counterpart_To_Oven;...endUI.Start_Button;Theimplementationofthedeletionofcounterpartswasdoneinthesamewayasforcreationofcounterpartobjects,butinsteadtheinstancesaredeleted.TheunidirectionalCOMfunctionalitywasnotimplemented,duetotimelimita-tions.6.3.2CounterpartEventMappingTheimplementationoftheCEMissimilartotheCOMimplementation.ThefollowingfunctioninvocationscreatesCEMsbetweentheStart ButtoneventsStart Button ClickedandStart Button Clicked TestandtheOveneventStart Cooking.Thelastparameter,True,declaresthatthemappingisunidirectional.Thismeansthatthemappingwillonlybevalidinonedirection.TheStart Button ClickedeventwillgenerateanStart Cookingevent,butnotviceversa..invokeCounterpart_Event_Mapping(COM_Ref,Start_Button,Start_Button_Clicked,Oven,Start_Cooking,True).invokeCounterpart_Event_Mapping(COM_Ref,Start_Button,Start_Button_Clicked_Test,Oven,Start_Cooking,True)Thefollowingcodeisgeneratedfromtheabovedenedmapping.ItshowstheGeneratefunctionintheStart Buttonobject.withMO.Oven;...packageStart_Buttonis...procedureGenerateis...--GenerateCounterpartEventscaseEvent.NameiswhenStart_Button_Clicked=�MO.Oven.Generate_Counterpart_Event_To_Start_Button(Event=�(MO.Oven.Start_Cooking,Oven_Event_Data),To_Instance=�Oven_Id);whenStart_Button_Clicked_Test=�MO.Oven.Generate_Counterpart_Event_To_Start_Button(Event=�(MO.Oven.Start_Cooking,Oven_Event_Data),To_Instance=�Oven_Id);whenothers=�null; 52ImplementationofImplicitBridging endcase;---...endGenerate;...endStart_Button;ToavoidcycliceventgenerationanewgenerationfunctioniscreatedforeachCEM.InthiscasethefunctionGenerate Counterpart Event To Start ButtonisgeneratedintheOvenobject.ItwillcontaineverythingthattheoriginalGeneratefunctioncontainsexceptagenerationtothecounterparteventcallingit.Thereisnoproblemwithhavinganeventmappedtomorethanoneeventandtohaveseveraleventsinonesequence.TheproblemwithcycliceventgenerationisstillapossibilitywhenhavingaCEMsequence.ThisproblemishardtosolveintheimplementationandmustbetakenintoconsiderationwhendeningtheCEMs.TheStart ButtonhastwoCEMsdened.BotharemappedtotheStart CookingeventintheOven.WhenaneventisgeneratedintheStart Buttonitischeckedinthecasestatementandiftheeventisamappedeventitwillgeneratethecoun-terpartevent.BecauseseveraloftheperformedCEMsintheMOSonlyneededtobeunidirec-tionalthisfunctionalitywasimplemented.6.3.3CounterpartAttributeMappingThefollowingfunctioncreatesaCAMbetweenthestoredattributesTimeinStart ButtonandRemaining Cooking TimeinOven..invokeCounterpart_Attribute_Mapping(UI_Timer_Is_Oven.Ctrpt_Object_Ref,Start_Button,Time,Oven,Remaining_Cooking_Time)ACAMcanonlybedeclaredbetweenthevalidattributetypesdiscussedinsection5.4.2.Theattributetypecheckisperformedinthisandifthemappingnotisvalidanerrorisgenerated.Thefollowingcodeshowsthegeneratedcodefromtheabovedenedmapping.TheTimefunctionreturnsthecurrentvalueoftheTimeattribute.AsaconsequenceofthemappingtheTimefunctionreturnsthevalueofthecounterpartattribute.IntheSet Timefunctionthecounterpartattributeisset.withMO.Oven;...packageUI.Start_Buttonis...functionTime(Instance:inInstances.Identification) 6.3MappingImplementation53 returnIntegerisOven_Id:MO.Oven.Instances.Identification;Oven_Tmp:Integer;beginOven_Id:=MO_To_UI_Bridge.Start_Button_To_Oven_Mapping.Select_One(Instance);Oven_Tmp:=MO.Oven.Instances.Instance_Attributes(Oven_Id).Remaining_Cooking_Time;returnOven_Tmp;endTime;...procedureSet_Time(Instance:inInstances.Identification;Time:inInteger)isOven_Id:MO.Oven.Instances.Identification;beginOven_Id:=MO_To_UI_Bridge.Start_Button_To_Oven_Mapping.Select_One(Instance);MO.Oven.Instances.Instance_Attributes(Oven_Id).Remaining_Cooking_Time:=Time;endSet_Time;...endUI.Start_Button;IftheRemining Cooking Timehadbeenofa\roattypeinsteadthefollowingcodeshowshowthecastingisimplemented.functionTime(Instance:inInstances.Identification)returnIntegerisOven_Id:MO.Oven.Instances.Identification;Oven_Tmp:Integer;beginOven_Id:=MO_To_UI_Bridge.Start_Button_To_Oven_Mapping.Select_One(Instance);Oven_Tmp:=Integer(MO.Oven.Instances.Instance_Attributes(Oven_Id).Remaining_Cooking_Time);returnTmp;endTime;6.3.4StateToAttributeValueMappingThefollowingfunctioncreatesanSTAVMbetweenCookingstateinOvenandLamp StatusinLeft Lamp.Themappingvalueis\Yellow"..invokeState_To_Attribute_Value_Mapping(Ctrpt_Mapping,Oven,Cooking,Left_Lamp,Lamp_Status,``Yellow'')Themappingwasimplementedbyaddingcodetotheactionprocedurethatisexecutedwhentheobjectentersamappedstate.Thefollowingcodeshowsthegeneratedcodefromthemappingdenedabove.withUI.Left_Lamp; 54ImplementationofImplicitBridging ...packageMO.Ovenis...procedureCooking_Action(The_Event:inInstance_Event;Instance:inoutInstances.Identification)isRight_Lamp_Id:UI.Right_Lamp.Instances.Identification;begin....Right_Lamp_Id:=MO_To_UI_Bridge.Oven_To_Right_Lamp_Mapping.Select_One(Instance);UI.Right_Lamp.Instances.Instance_Attributes(Right_Lamp_Id).Lamp_Status:=Ada.Strings.Unbounded.To_Unbounded_String("Yellow");...endCooking_Action;...endMO.Oven;Theimplementationislimitedtoattributesofthestringtype.6.3.5NewStateTransitionToAttributeValueMappingThefollowingfunctioninvocationcreatestwoNSTAVMs.Therstfunctionde-nesthatwhenaCooking Period OvertransitionisperformedwhentheOvenobjectisinthestateCookingtheLamp StatusattributeintheRight Lampissetto\white".ThesecondfunctionsetsthesameattributetothesamevaluebutwhenaCancel Cookingtransitionisperformed..invokeNew_State_Transition_To_Attribute_Value_Mapping(Ctrpt_Object_Mapping,Oven,Cooking,Cooking_Period_Over,Right_Lamp,Lamp_Status,``white'').invokeNew_State_Transition_To_Attribute_Value_Mapping(Ctrpt_Object_Mapping,Oven,Cooking,Cancel_Cooking,Right_Lamp,Lamp_Status,``white'')Thefunctionsabovedenethesamebehaviourinthewaythattheysetthesameattributetothesamevaluewhenleavingthesamestate.ThereforethefollowingfunctionhasbeenimplementedintheArchitecturethatforagivenobjectandstateinvokestheabovefunctionsforallexittransitionsthataredenedinthestate.Allmappingswillbemappedtothesametargetobjectattributeandwiththesamevalue..functionExit_State_To_Attribute_Value_Mapping(Ctrpt_Object_Mapping, 6.3MappingImplementation55 Oven,Cooking,Right_Lamp,Lamp_Status,``white'')TheimplementationfortheNSTTAVMistoaddcodeinthoseplaceswherethemappedobjectstatereceivesstatetransitions.Thefollowingcodeshowsthegeneratedcodefortheaboveinvokedfunctions.withUI.Right_Lamp;...packageMO.Ovenis...procedureState_Event_Matrix(Instance_State:inoutState;Transition_Event:inInstance_Event;State_Transition_Occurred:outBoolean;Instance:inInstances.Identification)isRight_Lamp_Id:UI.Right_Lamp.Instances.Identification:=MO_To_UI_Bridge.Oven_To_Right_Lamp_Mapping.Select_One(Instance);beginState_Transition_Occurred:=True;caseInstance_StateiswhenAwaiting_Cooking_Request=�caseTransition_Event.NameiswhenStart_Cooking=�Instance_State:=Ensuring_Safe_To_Cook;whenothers=�State_Transition_Occurred:=False;--EventIgnoredendcase;whenCooking=�caseTransition_Event.NameiswhenCooking_Period_Over=�Instance_State:=Signalling_Cooking_Period_Over;UI.Right_Lamp.Instances.Instance_Attributes(Right_Lamp_Id).Lamp_Status:=Ada.Strings.Unbounded.To_Unbounded_String("White");whenCancel_Cooking=�Instance_State:=Cooking_Suspended;UI.Right_Lamp.Instances.Instance_Attributes(Right_Lamp_Id).Lamp_Status:=Ada.Strings.Unbounded.To_Unbounded_String("White");whenothers=�State_Transition_Occurred:=False;--EventIgnoredendcase;endcase;endState_Event_Matrix;...endMO.Oven; 56ImplementationofImplicitBridging 6.4HowtheMappingInformationisStoredTheArchitecture,ormodelcompiler,wereextendedwithfunctionsthatareusedtopopulatethegenerationdatabasewithbridginginformation.Anexampleofafunctionforpopulatingthegenerationdatabase:.functionCounterpart_Object_Mapping.paraminst_refIB#ImplicitBridge.paramstringCtrpt_Mapping_Name.paramstringSrc_Domain_Name.paramstringSrc_Obj_Name.paramstringTgt_Domain_Name.paramstringTgt_Obj_Name.//.createobjectinstanceCtrpt_Obj_MapofBR_COM.assignattr_Ctrpt_Obj_Ref=Ctrpt_Obj_Map.//.//.selectoneSrc_DomainrelatedbyIB-�S_DOM[R109]where(selected.Name==Src_Domain_Name).selectoneTgt_DomainrelatedbyIBe-�S_DOM[R110]where(selected.Name==Tgt_Domain_Name).//.if(emptySrc_Domain).selectoneSrc_DomainrelatedbyIB-�S_DOM[R110]where(selected.Name==Src_Domain_Name).selectoneTgt_DomainrelatedbyIB-�S_DOM[R109]where(selected.Name==Tgt_Domain_Name).endif.//.selectoneSrc_ObjrelatedbySrc_Domain-�S_SS[R1]-�O_OBJ[R2]where(selected.Name==Src_Obj_Name).selectoneTgt_ObjrelatedbyTgt_Domain-�S_SS[R1]-�O_OBJ[R2]where(selected.Name==Tgt_Obj_Name).//.assignCtrpt_Obj_Map.BR_COM_ID="{info.unique_num}".assignCtrpt_Obj_Map.Src_Obj_ID=Src_Obj.Obj_ID.assignCtrpt_Obj_Map.Tgt_Obj_ID=Tgt_Obj.Obj_ID.assignCtrpt_Obj_Map.Mapping_Name=Ctrpt_Mapping_Name.assignCtrpt_Obj_Map.BR_IB_ID=IB.BR_IB_ID.//.endfunction 6.5HowtheMappingInformationisUsed57 6.5HowtheMappingInformationisUsedWhenthecodegenerationbeginsallthebridginginformationmustavailableinthegenerationdatabase.WhendeningaCOMbetweentwoobjectstheabovefunctionmustbeinvoked.AnexampleforcreatingaCOMbetweentheDoorandtheLeft Lampobjects:.invokeCounterpart_Object_Mapping(Impl_Bridge,Door_To_Left_Lamp,MO,Door,UI,Left_Lamp)Theinvocationoftheabovefunctionstoresinformationaboutthismappinginthegenerationdatabase.Whenthecodegenerationbeginsthebridginginformationcreatedabovewillbeavailablebyinvokingthefollowingstatement.selectmanyCtrpt_Objectsrelatedbycurrent_object-�BR_COM[R101].foreachCtrpt_ObjectinCtrpt_Objects{Ctrpt_Object.Name}.Create_Counterpart_To_{curren_object.Name}({Ctrpt_Object.Name}_Id).endfor 58ImplementationofImplicitBridging 6.6MappingLimitationsTheabovediscussedmappinginvocationsareorganizedintotwolestypesthebridgeleandtheserverinterfacele.Theserverinterfacelecontainsaninterfaceforwhichmappingsthatareavailableforitsclients.ThefunctionsdenedintheinterfaceleinturninvokethebridgefunctionsintheextendedArchitecture. Figure6.4.Theclientandserverlemodel.Whentheclientwantstocreateamappingitinvokestheappropriatefunctionintheserverinterface.Allinvocationsaredenedinthebridgeleandthisleisuniqueforeachbridge.Hencethebridgelecontainstheservicestheclientdomainrequiresfromtheserverdomain.6.6.1TranslationProcessIngure6.5themodicationstothetranslationprocesscanbeseen.Thenewcomponentinthegureisthebridgingmetamodel.Themainimplementationwereperformedinthemodelcompilerwerethearchetypesforimplicitbridgingaredened. 6.6MappingLimitations59 Figure6.5.Translationprocess. 60ImplementationofImplicitBridging Chapter7EvalutationThischapterevaluatestheimplementationandcomparesittoanearlierimple-mentation.7.1VericationofImplementationThefollowingsectionwilldiscusstheresultofthethesisworkandrelateittothegoalsofthework,see1.47.1.1ImplementedMappingsTheMOSwereanalysedanditresultedinasetofmappingsthatallwereimple-mented.7.1.2SystemgenerationTheMOScansuccessfullybegeneratedandcompiledintoarunningsystem.Allimplementedmappingsdescribedinthepreviouschapterareimplementedandworking.7.1.3VericationoffunctionalityTheindependencybetweentheparticipatingdomainsiseasytoshowbyremovinganyofthebridginglesduringthetranslation.ToevaluatetheimplicitbridgingfunctionalitynotonlythefunctionalmappingintheMOScanbetakenintocon-sideration.Itisimportanttoshowthatitissimpletoadd/removedomainsin61 62Evalutation thesystem.ThisfunctionalitywasveriedbyusingtheTestdomain.TheTestdomainwasusedintwocases:1.Whenusingalldomains,maptheUIdomainontotheTestdomain2.RemovingtheUIandGUIdomainsandmaptheMWdomainontotheTestdomain.Bothtestcasesweresuccessfulandwasasexecutedwithoutanyproblems.ThisshowedthesimplicitytoaddadomainwithoutchangingthextUML-modelanditalsoshowedthatwhendomainsareindependentofeachothertheycanbere-used. 7.2EarlierImplementation63 7.2EarlierImplementationTherehasbeenanearlierimplementationofimplicitbridgingintheADAmodelcompiler.Thisimplementationonlysupportedonemapping,the\AttributeToMessageWordMapping".Thissolutionhasnotbetakenintoconsiderationwhenimplementingthenewfunctionality.Thisreasonfornotdoingthatisthatitiseasytobecoloredbyanexistingimplementationandthatmakesithardertondnewsolutions.7.2.1FunctionalityThefunctionalityoftheAttributeToMessageWordMappingisthatthecurrentvalueofanattributeintheclientdomainismappedtoaninstanceofanobjectinaserverdomain.Theserverobjectisawordinamessage. 7.2.2ComparisonThemaindierenceisthattheearlierimplementationdoesnothaveanydynamicbehaviour.Themappingsisperformedonanpre-existinginstanceoftheword 64Evalutation object.Thisimplementationcouldbeusefulwhenimplementingmappingtopre-existinginstanceinthenewimplicitbridgingimplementation.ThemappingsaredierentbecauseitusesbridgedelementsinsteadofelementsintheOOAtomapbetween.Otherwisebothapproachesaresimilar. 7.3ImplicitBridgingWork\row65 7.3ImplicitBridgingWork\rowTheimplementationofimplicitbridgingandspeciallythemappingscanbestruc-turedintoanstepbystepwork\row.Thisapproachwasusedwhenimplementingthemappingsdescribedinthisthesis.Step1Thoroughlyanalysethemappingbeforeimplementation.Thisisimportantbecauseoftheoverheadofanimplementation.Step2ExtendtheBridgingMetamodelbyconstructingthehalftablesforthenewmap-ping.Thehalftableasdescribedinchapter3hasuniqueelementsfrombothsourceandtargetdomains.Step3Doanmanualimplementationofthemappingthatistobeimplemented.Thishelpsalotwhencreatinganarchetypegeneratingthesamecode.Step4Writethearchetypebasedontheimplementedcodeinstep3.Step5Deneanserverinterfaceusingthenewmappingandgeneratethesystem. 66Evalutation 7.4ErrorManagementAllmappingsshouldhavesomeformoferrormanagement.Themappingsimple-mentedinthisthesisworkincludeserrorcheckingfunctionality.Theerrorchecksthatareperformedarebridgescannotbecreatedtothesamedomain,existenceofmappingelements,typechecking.Deningabridgetothesamedomainshouldnotbepossible.Ifthisisneededthesystemisinneedofare-design.Thismeansthatfunctionalitythatbelongstoonedomainwillbehiddeninthebridge.Tocheckforexistenceofelementsisimportanttoreducethepossibilityforrun-timeerrors.Thisishelpfulifamisspellorsimilarshouldhappedwhendeclaringanmapping.Typecheckingisimportantwhenusingthecounterpartattributemapping.Thismappingonlypermitsalimitednumberoftypecombinations.Whenanerrorisdiscoveredwhenperformingthebridgingthecompilationishaltedandanerrormessageispresentedtotheuser. Chapter8SummaryThischapterwillgiveasummaryofthethesiswork.Itwillalsodiscusshowtheimplicitbridgingtechniquecouldbeusedinfutureimplementations.8.1ConclusionThegoalwiththisthesisworkwastoinvestigateandimplementthetechniqueimplicitbridging.Theimplementedmappingsarefullyfunctionalandthefunc-tionalityhasbeenveriedbyapplyingthemintheMOS.Thethesisworkshowedthatthereissomeoverheadinimplementingamapping.Eachmappingmustbethoroughlyanalystbeforeitisimplemented.Importantthingstotakeintoconsiderationarethatamappingmustsavetimecomparedtothetimeittakestoswitchdomainswhenusingexplicitbridging.Thismeansthatmappingsthatcausesalotofcouplingbetweendomainsshouldhavehigherprioritytobeimplementedcomparedtothosecausinglesscoupling.WhenthethesisworkstartedIhadalmostnoknowledgeaboutthistopicanditwashardtofullyunderstandthecomplexityoftheproblemarea.Thisareaisinthefrontendofsoftwaredevelopmentanditcanbediculttondmaterialdescribingthetopic.AftersomeweeksandalotofreadinganddiscussionwithmysupervisorIrealizedthecomplexityoftheproblem.ThedecisiontobuildtheimplementationaroundtheMOSwasveryhelpful.Itresultedinagroundfounda-tionforunderstandingtheproblemandresultedinwhichmappingtoimplement.Thiswasoneoftheimportantstepsthatshowedthatitisveryimportanttohaveagreatknowledgeofthesysteminwitchimplicitbridgingshallbeapplied.Theimplementedmappingsareonlyanexampleofhowthetechniquecouldbeused.Therearemanymoretypesofmappingsthatcouldbeapplied.Especiallymap-pingstopre-existinginstances,aninstanceiscreatedwhenthesystemstarted,wouldbeveryusefulwhenmappingtotheTestdomain.Therearemanymore67 68Summary mappingsthatcouldbeexplainedbuttheimplementedmappingsarefullyfunc-tionaleventhoughsomeofthemshallnotbeused.TheresultingimplementationcancompileseveralxtUML-modelsintoanrunningsystemanduseimplicitbridg-ingtodenethebehaviourbetweenthedomains.Theimplicitbridgingtechniquehasbeenshowntobeveryhelpfulwhenadding/removing/switchingdomain.ThetestdomainwasimplicitlybridgedbothtotheUIandtheMOdomainsusingthesameinterface.Thisshowthatthedomainscanbereusedwithoutchangingthemodels. 8.2FutureWork69 8.2FutureWorkTheimplementedmappingswereallbasedontheMOS.Thesemappingscanbeusedinothersystemsbuttherewillalsoberequirementsfornewmappings.Thisthesisworkisafoundationforimplicitbridgingandwillbeanimportantaidwhenaddingmoremappingsinthefuture.8.2.1FutureMappingsHereisadiscussionaboutsomemappingsthatwerenotimplementedbutfoundtobeveryusefulorextensionsoftheimplementedmappings.Thesemappingproposalsshouldbetakenintoconsiderationwhenextendingtheimplicitbridgingfunctionality.Amappingthatwasdiscoveredtobeveryusefulwastheobjecttopre-existinginstancemapping.Itwouldbeveryusefulwhenforexampleperformingtestononedomain.Thecounterparteventmappingcouldtakeadvantageofthismapping.Relatedtothetestdomaindiscussedinpreviouschapteritwouldeliminatetheneedfortestobjects.InsteadtheonlyneededobjectintheTestdomainistheTestSequenceobject.Itwouldbeapre-existinginstanceandotherobjectscouldmapontoit.ItwouldthenbeenoughtocreatecounterparteventstotheeventsintheTestSequence.Thecounterpartattributemappingshouldincludethepossibilitytohaveancon-vertingfunction.Thepurposeofthefunctionistoconvertthemappedvalueintoavaluethatiswantedbythesourcedomain.AnexampleiswhenanvalueisalatitudevalueitwouldsometimebeusefultoconvertitintoancoordinateThecounterpartobjectmappingshouldsupportunidirectionalfunctionality.8.2.2ErrorManagementIntheimplementationthereisnocheckforcycliccreationofobjects.Thereforeitisuptothedesignerthatdenesthebridgestakesthisproblemintoconsideration.Asimplesolutiontothisproblemistoimportthemappedobjectsintoagraph. 70Summary AppendixABridgeMetamodel71 72BridgeMetamodel 73 74BridgeMetamodel 75 76MicrowaveModel AppendixBMicrowaveModel is housed inR1houses 11illuminatesR2is illuminated by 1is located inR3features 11is accessed viaR4provides access to 11occupiesR5has OvenID : unique_id {I}TubeID : unique_id {R1}LightID : unique_id {R2}BeeperID : unique_id {R3}DoorID : unique_id {R4}TurntableID : unique_id {R5}Current_Oven_Timer_Value : integer {M} TubeID : unique_id {I} LightID : unique_id {I} BeeperID : unique_id {I} DoorID : unique_id {I} TurntableID : unique_id {I} AppendixCUserInterfaceModel77 78UserInterfaceModel 79 80UserInterfaceModel AppendixDTestModel81 82TestModel AppendixEMicrowaveSystem-DomainChart 83 84MicrowaveSystem-DomainChart 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