Model-Driven Evolution of Software Architectures - Software and ...
Model-Driven Evolution of Software Architectures - Software and ...
Model-Driven Evolution of Software Architectures - Software and ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
7.8. Transformation 157<br />
rule ResourceUsage {<br />
from s:UML!SimpleState (s.isWait)<br />
to cu: TRS!CapabilityUsage (<br />
capability select(a|a.script.body=s.<br />
outgoing->select(t|t.effect.isClaim).effect.script.body))<br />
}<br />
Listing 7.5:Ruleforresourceusagepattern<br />
callthe getResourceClaimshelperthatrecursivelyfindsall ≪wait≫States<br />
bybackwardstraversal<strong>of</strong>thestatemachineuntila≪release≫Actionis<br />
encountered. A ≪release≫Actionreleasesallclaimedsubsystems. The<br />
≪wait≫StatesinthereturnedsetmatchtheResourceUsagerule<strong>and</strong>the<br />
BehaviourislinkedbyitsrequiresattributetothecorrespondingCapabilityUsageelements.<br />
Resourcesetups Inthetargetmodel,setupsareautomaticallyinsertedby<br />
thegeneric(solving)part<strong>of</strong>theproduct-linearchitecture. Thisisdoneat<br />
run-time,basedonmismatchingbeginState<strong>and</strong>endStateattributes<strong>of</strong>the<br />
CapabilityUsageelement.Tosomeextent,thesecouldbederivedfromthe<br />
explicitlyspecifiedsetupsinthesourcemodel.<br />
Inthischapter,however,wedonotdefineacorrespondingtransformationruleasitdependsheavilyondomainknowledge.Usingourtransformations,setupswillexplicitlyendupinthetargetmodelasjustanother<br />
task<strong>and</strong>behaviour.Assaid,thisensuresthatthemigratedcontrolsystem<br />
mimicsthebehaviour<strong>of</strong>thelegacycontrolsystemexactly,thusresulting<br />
inavalidated<strong>and</strong>acceptablebaseline.<br />
Synchronousexecution ThetargetmodeldefinesprecedencerelationsbetweenthoseTasksthatrequiresynchronisation(withinthesameRequest).Inprinciple,theserelationsfollowfromtheexecutionorder<strong>of</strong>themanufacturingactivities<strong>and</strong>thecorrespondingActionswithinanormalisedstatemachine.Inaddition,(virtual)resourcescanbeusedforexternalsynchronisation.<br />
ForsynchronisationwithinaRequest,predecessorrelationsarecreated<br />
foreverytaskbysearchingforitsset<strong>of</strong>(direct)predecessortasks. For<br />
thiswehavedefinedtwohelpersthatbothoperateontheelementsthat<br />
matchrulesthatcreateTasks.ThefirsthelperisdepictedinListing7.6on<br />
thefollowingpage<strong>and</strong>isdefinedonStateVertexwhereasthesecondone<br />
isdefinedonGuard. ForeachTask,one<strong>of</strong>these getPredecessorshelpers<br />
isinvokedonitscorrespondingStateVertexorGuard. Thesehelpersdeterminewhetherthecurrentelement(self)correspondstoatask.<br />
Ifso,<br />
thiselementisreturned. Otherwise,thehelperisrecursivelyappliedto
Change language