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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8.6. Discussion 185<br />
8.6 Discussion<br />
Ourapproachhasseveralbenefits. Itreducestheeffortrequiredforthe<br />
introduction<strong>of</strong>MDEapproachesbycircumventingtheneedtospecifically<br />
developgraphicaleditorsforthevisualisation<strong>of</strong>DSMLmodels. FurthermoreitallowstointroduceanMDEapproachgradually;UMLdiagramscan<br />
continuetobeusedfordocumentationpurposes. Assuch,inthecase<strong>of</strong><br />
s<strong>of</strong>twarearchitecture,itfacilitatestheintegration<strong>of</strong>ADLs<strong>and</strong>supporting<br />
toolsinindustrialdevelopmentprocesses.<br />
AspresentedheretheapproachusesMDAtechnologyformodeltransformations<strong>and</strong>metamodelling.Theunderlyingideasareapplicabletoother<br />
MDEapproachesaswell:eitherbyusingtheavailabletransformation<strong>and</strong><br />
metamodellingtechnologiesforthatMDEapproach,orbyimplementinga<br />
bridgetoMDA.Wegaveanexample<strong>of</strong>thelatterinSection8.4.2forXML.<br />
Ofcourse,thediagramsthataregeneratedautomaticallyusingourapproach,onlyconstituteaminorpart<strong>of</strong>thecompletedocumentation.Architecturalviews,forinstance,typicallyalsodocument(some<strong>of</strong>)therationale<strong>and</strong>trade-<strong>of</strong>fsthatunderliedesigndecisions[Clementsetal.,2002a].<br />
Infact,anarchitecturalviewcanbeseenas‘diagrams+explainingtext’.<br />
Althoughthe‘explainingtext’isnotautomaticallyupdatedusingourapproach,itdoesprovideastartingpointfordoingso(i.e.,thenewlygenerateddiagram).<br />
WhetheramappingtoUMLisfeasible,dependsonthetype<strong>of</strong>models<br />
involved<strong>and</strong>thedocumentationrequirements.Apotentialrisk<strong>of</strong>ouruse<br />
<strong>of</strong> UML,isthatthe UMLsemanticsmightnotmatchwiththesemantics<br />
<strong>of</strong>therepresented(DSML)modelelements,resultinginambiguities. In<br />
thesecasesappropriatestereotypesshouldbeintroduced.Asanexample,<br />
considerthestereotypesinFigure8.4(c)onpage178. Thesestereotypes<br />
areincludedintheATLmappingswedefined.<br />
Inthecasethatthesemanticgapbetweentheinvolvedmetamodel<strong>and</strong><br />
UMListoolargetobesolvedwithstereotypes,instead<strong>of</strong>UML,moregeneric<br />
graphlanguagessuchasdot 1 <strong>and</strong>GXL 2 couldbeusedastarget<strong>of</strong>themapping.<br />
Theeffortrequiredforspecification<strong>of</strong>themappingstoUMLismainly<br />
determinedbythecomplexity<strong>and</strong>size<strong>of</strong>theDSMLmetamodel.Typically,<br />
thesearerelativelysmall(e.g.,comparedtoUML).Furthermore,suchmappingscanbeeitherspecificallydeveloped(asinthecase<strong>of</strong>task-resource<br />
models)orreused(asinthecase<strong>of</strong>ADLs).Inthelattercasetheyonlyneed<br />
tobespecifiedasamodeltransformation.<br />
1 dot-LanguageusedbyGraphviz(GraphVisualisationS<strong>of</strong>tware),seehttp://www.<br />
graphviz.org(June2007)<br />
2 GXL-GrapheXchangeLanguage,seehttp://www.gupro.de/GXL(June2007)
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