Model-Driven Evolution of Software Architectures - Software and ...
Model-Driven Evolution of Software Architectures - Software and ...
Model-Driven Evolution of Software Architectures - Software and ...
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82 Chapter5. <strong>Model</strong>-<strong>Driven</strong>ConformanceChecking<br />
5.3 RelatedWork<br />
Several formal approaches have been proposed that address problems<br />
similartoours. Lam<strong>and</strong>Padget[2003]translateUMLstatechartsinto πcalculustodeterminebehaviouralequivalenceusingbisimulation.Schäferetal.[2001]presentatoolthatusesmodelcheckingtoverifystatemachines<br />
against collaboration diagrams. The use <strong>of</strong> such tools <strong>and</strong> approachesrequirescomplete,precise<strong>and</strong>integratedinteraction-<strong>and</strong>statebasedbehaviouralmodels.<br />
Thisimplies,forinstance,thatsending<strong>and</strong><br />
reception<strong>of</strong>messagesinscenariosareexplicitlylinkedtoevents<strong>and</strong>effectsinstatemachines.<br />
Inourcase,forthesequencediagrams,thisis<br />
problematic. Theyarecreatedearlyinthedevelopmentprocess<strong>and</strong>not<br />
intendedtobecompleteorprecise.<br />
Totakethisintoaccount,wegenerateastatemachinefromaset<strong>of</strong><br />
inputscenarios,that,subsequently,iscomparedtothestatemachinethat<br />
wascreatedbythedevelopers.<br />
Manyapproacheshavebeendefinedforsynthesis<strong>of</strong>state-basedmodels<br />
fromscenario-basedmodels. Amyot<strong>and</strong>Eberlein[2003],<strong>and</strong>Liangetal.<br />
[2006]bothevaluateovertwenty<strong>of</strong>them.Evaluationcriteriaincludelanguages,meanstodefinescenariorelationships<strong>and</strong>statemodeltype.Our<br />
industrialcasegivesustherequirementswithrespecttothesecriteriafor<br />
asynthesisapproach.<br />
Instead<strong>of</strong>usingamorepowerfulscenariolanguagesuchaslivesequencecharts[Damm<strong>and</strong>Harel,2001],welimitourselvestoUMLsequence<br />
diagramsaugmentedwithdecorations,asdictatedbyourindustrialcase<br />
study.Thedecorationswithstateinformationcanbeinterpretedasconditionsfromwhichinter-scenariorelationshipscanbederived.Finally,with<br />
respecttostatemodeltype,weconsiderapproachesthatresultinstate<br />
modelsforindividualcomponents(instead<strong>of</strong>globalstatemodels). ConsideringLiangetal.[2006]oneapproachbestmeetstheserequirements,<br />
namelytheoneproposedbyWhittle<strong>and</strong>Schumann[2000].<br />
Whittle<strong>and</strong>Schumann[2000]presentanalgorithmtomap UMLsequencediagramstoUMLstatecharts.<br />
Inthismappingthemessagesina<br />
scenarioarefirstannotatedwithpre-<strong>and</strong>postconditionsonstatevariables,<br />
referredtoasadomaintheory. Themappingisbasedontheassumption<br />
thatamessageonlyaffectsastatevariableifitspre-orpostconditionexplicitlyspecifiesitdoes;thedomaintheorydoesnotneedtobecomplete.<br />
Thus,thisso-calledframeaxiom 1 ,togetherwiththepre-<strong>and</strong>postconditions,resultsinapair<strong>of</strong>statevectorsforeachmessage(before<strong>and</strong>after).<br />
1 Thenamederivesfromacommontechniqueusedbyanimatedcartoonmakerscalled<br />
framingwherethecurrentlymovingparts<strong>of</strong>thecartoonaresuperimposedonthe<br />
‘frame’,whichdepictsthebackground<strong>of</strong>thescene,whichdoesnotchange(http://en.<br />
wikipedia.org/wiki/Frame_problem(June2007)).
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