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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9.3. S<strong>of</strong>twareProductLines(RQ2) 193<br />
9.3 S<strong>of</strong>twareProductLines(RQ2)<br />
InChapter3wesignalledatrendtowardsapproachesthatallowamore<br />
structuredform<strong>of</strong>reusecomparedtotheadhoctype<strong>of</strong>reusethatistypicalinindustry.<br />
Inthiscontextproductlines<strong>and</strong>MDEaretwoimportant<br />
developments. Weobservedthatdifferentcompaniesareorganisingtheir<br />
s<strong>of</strong>twaredevelopmentsuchthattheirproductsaredevelopedaspart<strong>of</strong>a<br />
s<strong>of</strong>twareproductline.<br />
Theimpact<strong>of</strong>aproduct-linearchitectureonours<strong>of</strong>twareevolution<br />
tasksistwo-fold:<br />
•Theuse<strong>of</strong>s<strong>of</strong>twareproductlinesmakesthetasksmorecomplicated<br />
becausethecorrespondingproduct-linearchitecturesaremoreabstract,applytomultipleproducts,<strong>and</strong>,hence,involvealargernumber<br />
<strong>of</strong>stakeholders;theirscopeislargerwithrespecttotheproducts<strong>and</strong><br />
stakeholdersinvolved.<br />
•Ontheotherh<strong>and</strong>,theuse<strong>of</strong>anarchitecturethatappliestoawhole<br />
set<strong>of</strong>productsimprovesthereturnoninvestmentforsolutionsthat<br />
applytoalltheseproduct-linemembers.<br />
Scope<strong>of</strong>S<strong>of</strong>twareProductLines In Chapter 4 we discuss how the use <strong>of</strong><br />
product-lineprinciplesmakess<strong>of</strong>twarearchitectureevaluationsmorecomplex.Thefindings<strong>of</strong>suchanevaluationaremorebasedonindirectevidence,asscenariosareidentifiedforproduct-linemembers<strong>and</strong>notforthe<br />
productlineasawhole. Furthermore,aproduct-linearchitecturehasa<br />
muchwiderscopethanasingle-productarchitecture,therebyincreasing<br />
thenumber<strong>of</strong>stakeholders. Ourapproachtakesintoaccountboththese<br />
effects.<br />
Werefinedthetypicalclassification<strong>of</strong>scenariosaseitherdirect(i.e.,<br />
scenariosthatdonotrequirechangestothecurrentarchitecture)orindirect(i.e.,scenariosthatdorequirechangestothecurrentarchitecture)<br />
bydistinguishingbetweentwotypes<strong>of</strong>directscenarios:concretescenarios<br />
<strong>and</strong>floatingscenarios.Theformerareexplicitlysupportedbytheproductlinearchitecture,whilethelatterarenotexplicitlysupported,butnotpreventedbyitaswell(rememberthatas<strong>of</strong>twarearchitectureisbothpermissive<strong>and</strong>restrictivewithrespecttotheimplementationsitallows).<br />
Thenumber<strong>of</strong>scenariosthatwillbecharacterisedasfloatingina<br />
product-linearchitectureevaluationdependsonitsmaturity.BythematurityscaleproposedbyBosch[2002],Océ’sproduct-linearchitecturecanbe<br />
characterisedasaplatform.Thismeansthatcommonalitiesareidentified<br />
<strong>and</strong>separatedoutasaplatform,butthatthevariabilitiesarenotmade<br />
explicit. Thisresultsinalargernumber<strong>of</strong>floatingscenarios. However,