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1、ApplicationsDevelopmentUsingDesignPatternstoImplementObject-OrientedMenusinaSAS/AFÒApplicationJackE.Fuller,TrilogyConsultingCorporation,Kalamazoo,MIABSTRACTselectiontothecodewhichwillbeexecuted;third,amethodforeasilyextendingthissystemOneofthemorefrustratingaspectsofdesigningtotheuniquer
2、equirementsofdifferentaGraphicalUserInterface(GUI)forSAS/AFapplications.applicationsliesinthebasicdifficultyofreconcilingobject-orientedprogrammingBUILDINGTHEMIRRORtechniqueswithSASÒsoftware’spmenus.Fundamentalobject-orientedconceptssuchasABoxInsideaBoxInsideaBoxInside…encapsulationandpo
3、lymorphismarenotbuiltFromastructuralperspective,apmenucanbeintopmenus.thoughtofassimplyatree.Forexample,apartiallyconstructedtreeofSASsoftware’sThispaperintroducesdesign-patternstobuildwindowpmenuwouldlooklikeasfollows:constructasystemthatbringspmenusintotherealmofobject-orientedprogramm
4、ing.ThekeyPmenuconceptisthatwhileaframestillrequiresatraditionalpmenuformenuing,allprogramminginteractionsarenowroutedthroughacorrespondingnon-visualobjectViewFileLocalsstructurewhichmirrorsthepmenuandprovidestheencapsulationandpolymorphismwhichwerepreviouslymissingfrompmenus.OpenSetDisp
5、layType...SynchronizeINTRODUCTIONFigure1Ihavebeenaskedthequestion,“WhyspendtheThisstructure,consistingofcontainerswithinefforttobuildanobject-orientedpmenu?Itcontainers,isanexampleofagenericdesign-seemstobesuchatrivialthing.”ForsomepatternknownasWhole-Part(Buschmann,et.minorpmenus(‘OK’,‘
6、Cancel’,‘Help’),thisisal.,pp.225-242).ThemainthrustofWhole-true;however,evensimplepmenuscancontainPartisthatanaggregationofpartscanbesurprisinglevelsofsophistication:e.g.untilatreatedtogetherasoneunit;fromtheoutside,fileisactuallyopened,‘File➠Close’shouldbeanyonelookingatthepmenustructur
7、egrayed.Thismayseemaminorpoint,butsincerepresentedinfigure1wouldseeonlythemenustendtobeoneoftheprimarymeansbyPmenucomponent.whichnewuserslearnasystem(i.e.apedagogicvector(Cooper,p.280)),aclientwillinevitablyAdditionally,thisstructurecanbefurtherselectit,crashthesystem,and
