oping无状态

xMOF:ASemanticsSpecicationLanguageforMetamodelingTanjaMayerhofer,PhilipLanger,ManuelWimmerBusinessInformaticsGroup,ViennaUniversityofTechnology,Austria{mayerhofer,langer,wimmer}@big.
tuwien.
ac.
atAbstract.
WhileMOFconstitutesastandardizedandwidelyacceptedlanguageforformallydeningamodelinglanguage'sabstractsyntax,nostandardizedlanguageforspecifyingitsbehavioralsemanticsexists.
Thisimpedestheef-cientdevelopmentoftoolswhichbuilduponthebehavioralsemanticsofmodel-inglanguages,suchasmodelinterpreters,debuggers,andtestingenvironments.
Toaddressthisshortcoming,weproposetoadoptthestandardizedactionlan-guagefUMLassemanticsspecicationlanguageinmetamodeling.
Inthispa-perwepresenttoolsupportintegratedwiththeEMFenvironmentforspecifyingthebehavioralsemanticsofmodelinglanguageswithfUMLaswellasforex-ecutingmodelsbasedonthesespecications.
Ateaserforthedemonstrationofthistoolsupportcanbefoundathttp://www.
youtube.
com/watchv=p4alBfqbjk8.
1IntroductionInmodel-drivenengineering(MDE),modelsconstitutethecentralartifactsinthesoft-waredevelopmentprocess.
Thus,thesuccessofMDEdependssignicantlyontheavailabilityofadequatetoolsupportforcreating,exploring,analyzing,andutilizingmodels.
Todevelopsuchtoolsefciently,modelinglanguages(i.
e.
,theirsyntaxandse-mantics)havetobedenedformally[1].
MOF[4]constitutesastandardizedandwidelyacceptedmetamodelinglanguageforformallydeningtheabstractsyntaxofmodelinglanguagesandlaidthegroundfortheemergenceofavarietyoftoolsbuildingupontheabstractsyntaxdenitionofamodelinglanguage,suchastechniquesforderivingmod-elingeditorsfromametamodelandgenericcomponentsformodelserializationandcomparison.
Despitethefactthatseveralapproachesforformallyspecifyingthebehav-ioralsemanticsofmodelinglanguageshavebeenproposedinthepast(cf.
[1]),noneoftheseapproachesiswidelyadoptedcomparedtometamodelinglanguages.
Thisham-perstheefcientdevelopmentoftoolswhichbuilduponthebehavioralsemanticsofamodelinglanguage,suchasmodelinterpreters,debuggers,andtestingenvironments.
Duetothislackofastandardizedlanguageforspecifyingthebehavioralseman-ticsofmodelinglanguages,weinvestigatedwhetherthestandardizedactionlanguagefUML[6]canbeusedassemanticsspecicationlanguageinmetamodelingandhowitcanbeintegratedwithexistingmetamodelingmethodologiesandenvironments.
ThisinvestigationresultedinthemetamodelinglanguageexecutableMOF(xMOF)integrat-ingfUMLwithEcore,whichisthemostprominentimplementationofMOFandem-ployedinEMF[7].
Furthermore,weelaboratedamethodologyforsystematicallydevel-opingsemanticsspecicationswithxMOFandutilizingthemformodelexecution.
Thismethodologyintegratesseamlesslywithexistingmetamodelingmethodologiesanden-vironmentswhichenabledustoimplementconformingtoolsupportforEMF1.
InSection2wegiveanoverviewofourmetamodelinglanguagexMOF.
InSec-tion3wepresentourmethodologyfordevelopingsemanticsspecicationsandexe-cutingmodelsbasedonxMOFanditstoolsupportinEMF.
InSection4wegiveanoverviewofthetooldemonstration.
Finally,inSection5weconcludethispaper.
2SemanticsSpecicationLanguagexMOFfUML[6]isasubsetofUML[5]comprisingmodelingconceptsfordeningUMLclasses,aswellasactivitiesdeningtheclasses'behavior.
Furthermore,fUMLdenestheexecutionsemanticsofthisUMLsubsetintermsofavirtualmachine(VM)capableofexecutingcompliantmodels.
BecauseUMLclassesandMOFmetaclassesdifferonlyintheirintendedusage(modelingofsystemsvs.
modelingoflanguages),wearguethatfUMLmightbewellsuitedforalsodeningthebehaviorofmetaclasses.
Furthermore,asfUMLisanobject-orientedandimperativeactionlanguageandwellknownintheMDEcommunityasitisasubsetofUML,whichiswidelyadoptedinMDE,itmightbeintuitivetouseforspecifyingthebehavioralsemanticsofmodelinglanguages.
AsbothMOFandfUMLarestandardizedbyOMG,fUMLmaybeconsideredaspromisingcandidateforbecomingastandardizedactionlanguageinmetamodeling.
ForintegratingfUMLwithexistingmetamodelinglanguagesinordertoenablethespecicationofthebehavioralsemanticsofmodelinglanguagesweidentiedtwostrategies[3]:atransformation-basedandanintegration-basedstrategy.
Becauseofthebetterintegrationwithexistingmetamodelingenvironmentswedecidedtoapplytheintegration-basedstrategy.
Inthisstrategy,ametamodelinglanguageisextendedwiththebehavioralpartoffUMLcomprisingmodelingconceptsfordeningactivitiesandactionssothatthebehaviorofmetaclassoperationsdenedinthemetamodelofamod-elinglanguagecanbespeciedintermsoffUMLactivities.
ByapplyingthisstrategyforintegratingfUMLwithEcore,whichisthemostprominentimplementationofMOF,weobtainedanewmetamodelinglanguagewhichwecalledexecutableMOF(xMOF).
ThemetamodelofxMOFisdepictedinFigure1.
ForintegratingEcorewiththebe-havioralpartoffUMLweintroducedthemetaclassesBehavioredEClassier,Behaviored-EClass,MainEClass,andBehavioredEOperation.
ThemetaclassBehavioredEClassierisasubclassofEClassierandcanownBehaviorsintermsofActivities.
Behaviored-EClassisaconcretesubclassofBehavioredEClassierandEClassandcanthereforeownActivities.
TheclassMainEClassisintroducedtodistinguishoneBehavioredEClassinasemanticsspecicationasthemainclasscontrollingtheexecutionofamodelcon-formingtothemodelinglanguage.
WealsointroducedasubclassofEOperationcalledBehavioredEOperationwhosebehaviorcanbedenedbyanActivity.
3MethodologyforDevelopingxMOFSemanticsSpecicationsWithxMOFitispossibletodenetheabstractsyntaxandthebehavioralsemanticsofmodelinglanguages.
TofosterthesystematicandefcientdevelopmentofbehavioralsemanticsspecicationsusingxMOF,aswellastheutilizationofthesespecications1ThemetamodelofxMOF,thesourcecodeofourtoolsupport,aswellasdemosandcasestudiescanbefoundatourprojectwebsitehttp://www.
modelexecution.
org.
Fig.
1:MetamodelofxMOF(excerpt)forexecutingmodels,weelaboratedadedicatedmethodologywhichisaccompaniedbyEMF-basedtoolsupport.
AnoverviewofourmethodologyisdepictedinFigure2.
Inthesemanticsspecication,thebehavioralsemanticsofamodelinglanguageisdevelopedstartingfromitsEcore-basedmetamodel.
Thebehavioralsemanticsisde-nedinanownartifactcalledxMOF-basedcongurationwhichisautomaticallyinitial-ized.
Inthisinitializationonesubclass(BehavioredEClass)ofeachmetaclassdenedinthemetamodelisgenerated.
Theyarecalledcongurationclassesandcanbeex-tendedwithadditionalattributes,references,operations,andactivitiesforspecifyingthebehavioralsemanticsofthemetaclasses.
Alsoadditionalcongurationclassescanbedened.
Furthermore,oneBehavioredEClasscalledInitializationisgeneratedwhichcanbeusedtodenesupplementarydatathatisnecessaryasadditionalinputforex-ecutingmodelsbasedonthissemanticsspecication.
Thisclasscanbeextendedwithattributes,references,andadditionalcontainedclassescalledinitializationclasses.
Inthemodelexecutionpreparation,preparatorytasksforexecutingamodelac-cordingtothexMOF-basedbehavioralsemanticsspecicationoftheusedmodelinglanguagearecarriedout.
InEMF,modelsconsistofinstancesofthemetaclassesde-nedintheEcore-basedmetamodeloftheusedmodelinglanguage.
Asthesemanticsofthesemetaclassesisdenedbytheoperationsintroducedinthecongurationclasses,themodeltobeexecutedhastoberepresentedintermsofinstancesoftherespectivecongurationclasses.
ThisrepresentationiscalledxMOF-basedmodelandisgeneratedautomatically.
Thesupplementarydataneededasinputforexecutingamodeldenedbytheinitializationclasseshastobeinstantiatedmanuallybythemodeler.
ThexMOF-basedmodelcanbeexecutedbyleveragingthefUMLVM(modelexe-cution).
Therefore,itisautomaticallyconvertedintoanfUML-basedmodelconformingtotheformatrequiredbythefUMLVM.
DuringtheexecutionthefUMLVMinterpretstheactivitiesspecifyingthebehavioralsemanticsofthemodelinglanguageandmanip-ulatesthefUML-basedmodelaccordingly.
TheresultoftheexecutionconsistsofthemanipulatedfUML-basedmodel(fUMLextensionalvalues)representingtheruntimestateoftheexecutedmodelaftertheexecutionnished.
Forenablingitsvisualizationmodelannotationsaregeneratedfortheexecutedmodel.
ForthiswemakeuseofEMFProles[2]whichisanmechanismforannotatingEMF-basedmodels.
Fig.
2:OverviewofoursemanticsspecicationapproachbasedonfUML4DemonstrationInthedemonstrationofourtoolsupportforspecifyingthebehavioralsemanticsofmod-elinglanguages,wewilldevelopaPetriNetmodelinglanguage(PNML)followingthemethodologyintroducedinSection3.
WewillshowcasehowthefollowingtasksareaccomplishedusingourEMF-basedtoolsupport:(i)initializationofthexMOF-basedcongurationfromtheEcore-basedmetamodelofPNML,(ii)specicationofthebe-havioralsemanticsofPNMLbyextendingthexMOF-basedconguration,(iii)execu-tionofPNMLmodelsbasedonthexMOF-basedcongurationofPNML.
TheEcore-basedmetamodelofPNML(cf.
Figure3a)denesthataNetconsistsofPlacesandTransitionswhereasaTransitionisassociatedwithatleastoneinputandoneoutputPlace.
ThexMOF-basedcongurationofPNML(cf.
Figure3b)consistsofthecongurationclassesNetConguration,PlaceConguration,andTransitionCongurationgeneratedforthemetaclassesofPNML.
ForthecongurationclassTransitionCong-urationtheoperationre()wasintroducedwhosebehaviorisspeciedbytheactivitydepictedinFigure3c.
ThisactivityspeciesthatfortheoutputplacesofatransitiontheoperationaddToken()iscalledwhilefortheinputplacesremoveToken()isinvoked.
Fur-thermore,theinitializationclassTokenwasintroducedwhichhastobeusedfordeningtheinitialtokendistributioninthenettoenabletheexecutingofaPNMLmodel.
5ConclusionWehavepresentedthemetamodelinglanguagexMOFintegratingfUMLwithEcore.
Itenablestodenethebehavioralsemanticsofmodelinglanguagesinanoperationalway.
Furthermore,wegaveanoverviewaboutourmethodologyfordevelopingxMOF-basedsemanticsspecicationsandutilizingthemformodelexecutionandwepresentedaccompanyingtoolsupportforEMF.
Toevaluatetheapplicabilityofoursemanticsspecicationapproach,wecarriedoutseveralcasestudiesinwhichwedevelopedthebehavioralsemanticsspecicationsofdistinctmodelinglanguagesandutilizedthesespecicationstoexecuteconformingFig.
3:ToolsupportforspecifyingbehavioralsemanticswithfUMLmodelsusingtheimplementedtoolsupport.
Insummary,thecasestudiesconrmedthatxMOF,itsaccompanyingmethodology,anditstoolsupportareapplicablefordeningthebehavioralsemanticsofdifferentkindsofmodelinglanguages.
Regardingthesuit-abilityoffUMLassemanticsspecicationlanguage,wecometotheconclusionthatduetoitsobject-orientedandimperativenature,fUMLishighlysuitable.
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