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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72 Chapter4. Evaluation<br />
Withrespecttothefuturereusepositioning<strong>of</strong>thereferencearchitecture<br />
wewouldexpect,lookingatitsreuse-orientedbusinessdrivers,thatOcé<br />
aimstoincreaseitsreusescope.Thisobjectiveissupportedbytheidentification<strong>of</strong>variousdirectfloatingscenarios,whichwillbeimplementedbythe<br />
developmentteaminacookbook(Figure4.4onpage69).Thisimpliesthat<br />
Océindeedforeseesthatthereusepositioning<strong>of</strong>thereferencearchitecture<br />
israisedfromplatformtos<strong>of</strong>twareproductlineinthenearfuture.<br />
Updates Maintainabilitywasthecentralqualityaspectintheevaluation.<br />
Oneaspect<strong>of</strong>maintainabilityisthepossibilitytoupdatethereference<br />
architecturewithdevelopmentsthattakeplaceinaproductinstantiation:<br />
duringtheobliquelinesinFigure4.2onpage62.Inordertosuccessfully<br />
implementaproposedupdatetwoissuesneedtobeconsidered: conformance<strong>and</strong>permissiveness.Conformanceistheextenttowhichtheproductarchitecture<strong>and</strong>referencearchitecturematch.<br />
Onemustspecifytheupdateinagreementwith<br />
theexistingreferencearchitecture.Thisisnecessary,forexample,topreventspecification<strong>of</strong>updatestocomponentsthatdonotexistatallinthe<br />
referencearchitecture. Thearchitecture<strong>of</strong>aproductmayundergosmall<br />
changesduringitsdevelopment.Consequently,theremaybeadiscrepancy<br />
betweentheproductarchitecture<strong>and</strong>thereferencearchitecture.Thediscrepancymayobstructthetransfer<strong>of</strong>architecturalfragments,e.g.,acookbookrecipe,fromthereferencearchitecturetotheproductarchitecture.<br />
Butitmayalsoobstructtheupdate<strong>of</strong>thereferencearchitectureitself.<br />
Todetectthesearchitecturaldiscrepancies<strong>and</strong>suggestpossiblerepairs,<br />
onecouldchecktheconformancebyfirstusingreverseengineeringtechniquestoraisethelevel<strong>of</strong>abstraction<strong>of</strong>concreteproductarchitectures<br />
<strong>and</strong>thencomparetheresultwiththereferencearchitecture[VanDeursen<br />
etal.,2004].Chapters5<strong>and</strong>ch:ewsa2005investigatehowtoassessconformance<strong>of</strong>architecturespecificationsautomatically.<br />
FutureworkDevelopatechniquetomeasuretheconformance<br />
<strong>of</strong>aproductarchitecturewithrespecttothereferencearchitecture<br />
onwhichitisbasedinordertoassessthepossibilitytotransferfragmentsfromaproductarchitecturetothereferencearchitecture.<br />
Thebarefactthataproducthasanarchitecturethatconformswiththe<br />
referencearchitecturedoesnotensurebyitselfthataproposedupdatewill<br />
besuccessful. Thereferencearchitecturealsohastobepermissivewith<br />
respecttotheupdate. Thereferencearchitecturemustprovidetheflexibilitytoincorporatetheproposedupdate.<br />
Anupdatemightviolatesome<br />
<strong>of</strong>thedesigndecisionstakenearlier;whetherthisisthecaseisinpracticegenerallyhardtoassess.<br />
Onereasonforthisisthatdesigndecisions
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