windows编程潘爱民com讲座续介绍一些重要的模式

软件设计模式(二软件设计模式(二内复习复习：patternDesignpatternsrepresentsolutionstoproblemsthatarisewhendevelo softwarewithinaparticularcontext关于patternpatternpattern复习：如何描述一个模Designpatternname，AliasesorAlsoKnownProblem，IntentorContext，RelatedExamples，Known复习：creationalFactory本质：用一个virtualmethod完成创建过

Structural一个product族的factorymethod构成了一个factory通过product原型来构造product，Clone+prototype通过一个构造算法和builder接口把构造过程与客 单实例类型，如何构造这单个实例？如 这单个实例把对象的获取过程与客

**77Adapter(一Converttheinterfaceofaclassintoanotherinterfacesexpect.Adapterletsclassesworktogethercouldn'totherwisebecause patibleSometimesatoolkitclassthat'sdesignedforreuseisn'treusableonlybecauseitsinterfacedoesn'tmatchthe-specificinterfaceanapplicationrequires.Adapter模式(二youwanttouseanexistingclass,anditsinterfacedoesnotmatchtheoneyouneed.youwanttocreateareusableclassthatcooperateswithunrelatedorunforeseenclasses,thatis,classesthatdon'tnecessarilyhavecompatibleinterfaces.(objectadapteronly)youneedtouseseveralexistingsubclasses,butit'simpracticaltoadapttheirinterfacebysubclassingeveryone.Anobjectadaptercanadapttheinterfaceofitsparentclass.Adapter模式Adapter模式(三Adapter模式(三–、Target、Adaptee、classadapter——objectadapter——

Adapter模式(四

Adapter模式(五class无法adaptadaptee的子类，但是可以重载adaptee的行object可以adaptadapteeHowmuchadaptingdoesAdapterPluggableUsingtwo-wayadapterstoprovide针对classadapter，用多重继承来实

使用C++继承机制实现class使用内嵌对象技术实现object使 对操作，供客户插入？——hook技术Adapter模式(Adapter模式(六RelatedC++COM中的模式8：Bridge(一Decouplean ionfromitsimplementationsothatthetwocanvaryindependently抽象(接口)与实现都非常。Bridge模Bridge模式(二Applicability：UsetheBridgepattern对一个实现的修改不影响客户(无须重新编译Bridge模式(三 ion,ion,Bridge模式(四二进制兼容对客户隐藏实现细

Bridge模式(五OnlyoneCreatingtherightImplementor如何创建？根据客户环境，或者通过Sharing资源管理 计数技UsingmultipleRelated–Related–Factory可以用来创建和配置Bridge模–与Adapter–handle：文件handle、窗口插StringRep(constcharintcount;char*rep;Counted

class{String(constStringString&operator=(constStringStringRepComposite模式(Composite模式(三–,Component,Leaf,典型的composite对象结99：Composite(一Composeobjectsintotreestructurestorepresentpart-wholehierarchiesCompositelets streatindividualobjectsandcompositionsofobjectsuniformly”递归组Composite模式(二youwant stobeabletoignoretheindividualobjects.swilltreatallobjectsinthecompositestructureuniformly.Composite模式(Composite模式(四objectsandcompositeobjects。定义了包含leafmakesthesimple。客户一致地处理复合对makesiteasiertoaddnewkindsofcomponentscanmakeyourdesignoverlygeneral。使得系统过于Composite模式(五ExplicitparentSharingizingtheComponentDeclaringthechildmanagementShouldComponentimplementalistofChildCachingtoimproveWhoshoulddeleteWhat'sthebestdatastructureforstoringComposite模Composite模式(六Related广泛应用于OO领MFC中的组件层次：ActiveX10：Facade(一Provideaunifiedinterfacetoasetofinterfacesinasubsystem.Facadedefinesahigher-levelinterfacethatmakesthesubsystemeasiertouse.Facade模式(三–Facade模式(三–facade,subsystemApplicability：UsetheFacadepattern FlyWeight模式(三FlyWeight模式(三FlyWeight模式(四Struct(续–,flyweight,concreteFlyweight,–Facade模式(四—— Facade模式(五Related–facade对象的创建：singleton MFCFakeMFCMapMapMapPluginMDINetscape1111：FlyWeight(一Usesharingtosupportlargenumbersoffine-grainedobjectsefficiently.当对象的粒度太小的时候，大量对象将会产生巨大的资源消耗，因此考虑用共享对象(lyegh)来实现逻辑上的大量对象。Flght对象可用于不同的onxt中，本身固有的状态不随onxt发生变化，而其他的状态随onxt而变化FlyWeight模式(二ofthefollowingaretrue:AnapplicationusesalargenumberofStoragecostsarehighbecauseofthesheertyofMostobjectstatecanbemadeManygroupsofobjectsmayberecedbyrelativelyfewsharedobjectsonceextrinsicstateisremoved.Theapplicationdoesn'tdependonobjectidentity.Sinceflyweightobjectsmaybeshared,identitytestswillreturntrueforconceptuallydistinctobjects.FlyWeight模式(FlyWeight模式(五把对象的状态分开：intrinsicand Removingextrinsicstate，尽可能做到实时计算(通过Managingsharedobjects，客户不能直接实例化 Related与Composite可以用flyweight实现State和Strategy用flyweight实现celltearoff“DesignPatternsStructuralStructuralPatternsStructuralPatternsStructuralpatterns小Adapter、bridge、composite用于构造对象组合结

BehavioralChainofResponsibilityInterpreter MediatorMementoStateTemteMethod12：12：Command(一Action,Encapsulatearequestasanobject,therebylettingyou swithdifferentrequests,queueorlogrequests,andsupportundoableoperations.Command模式(二parameterizeobjectsbyanactiontoperformspecify,queue,andexecuterequestsatdifferentsupportsupportloggingchangessothattheycanbereappliedincaseofasystemcrashstructureasystemaroundhigh-leveloperationsbuiltonprimitivesoperations——transactionsCommand模Command模式(三 Command模式(四

Command模式(五Related模式可用来实 mand组为实现Related模式可用来实 mand组为实现o，可以用其他行为模式来管理状态，如模式。 mnd被放到istrylst之前，可以prototype模 自Commandsarefirst-classobjectsTheycanbemanipulatedandextendedlikeanyotherobjectYoucanassemblecommandsintoacompositecommandAnexampleis It'seasytoaddnewCommands,becauseyoudon'thavetochangeexistingclassesHowinligentshouldacommandSupportingundoandAvoidingerroraccumulationintheundoUsingC++tem模式模式 tor(一ProvideawaytoaccesstheelementsofanaggregateobjectsequentiallywithoutexposingitsunderlyingAnaggregateobjectsuchasalistshouldgiveyouawaytoaccessitselementswithoutexposingitsinternalSeparatingthetraversalmechanismfromtheListobjectletsusdefinei torsfordifferenttraversalpolicieswithoutenumeratingthemintheListinterface. tor模式(二 torpatternwhenexposingitsinternalrepresentation.toprovideauniforminterfacefortraversingpolymorphici tor模式(三– tor、 tor模式(四Itsupportsvariationsinthetraversalofan torssimplifytheAggregateMorethanonetraversalcanbependingonanWhocontrolsthe externalitorversusinternaliWhodefinesthetraversal——itor定义算法——itor如何数Howrobustisthe tor模式(五Implementation(续Additional tor基本操作：First,Next,IsDone,andUsingpolymorphic tors torsmayhaveprivileged torsforcomposites——适合于internali Null

常被用 posite模式的复合结Polymorphici torsrelyonfactorymethodstoinstantiatetheappropriateICOMenumerator：connectableobject、C++在STL中，itor是连接algorithm和container14：14：Observer(一Aliases：Dependents,Publish-Defineaone-to-manydependencybetweenobjectssothatwhenoneobjectchangesstate,allitsdependentsarenotifiedandupdatedautomatically. ThekeyobjectsinthispatternaresubjectandAsubjectmayhaveanynumberofdependentAllobserversarenotifiedwheneverthesubjectundergoesachangeinstateObserver模式(二Whenan ionhastwoaspects,onedependentontheother.Encapsulatingtheseaspectsinseparateobjectsletsyouvaryandreusethemindependently.Whenachangetooneobjectrequireschangingandyoudon'tknowhowmanyobjectsneedtobeWhenanobjectshouldbeabletonotifyotherobjectswithoutmakingassumptionsaboutwhotheseobjectsare.Inotherwords,youdon'twanttheseobjectstightlyObserver模式Observer模式(三–Subject、ConcreteSubject、Observer、Observer模式(四

Observer模式(五Observer模式(六Mediator：用Mediator模Observer模式(六Mediator：用Mediator模式封装复杂的更新语COMpropertyCOM+EventSupportforbroadcastUnexpected subjectstotheirObservingmorethanoneWhotriggersthe orMakingsureSubjectstateisself-consistentbeforesubject向observer传递变化信中间插入15：15：Strategy(一Defineafamilyofalgorithms,encapsulateeachone,andmaketheminterchangeable.Strategyletsthealgorithmvaryindependentlyfrom sthatuseit.Strategy模式(二manyrelatedclassesdifferonlyintheiryouneeddifferentvariantsofananalgorithmusesdatathat asmultipleconditionalstatementsinitsStrategy模Strategy模式(三Strategy、ConcreteStrategy、StrategyandContextincttoimplementthechosenAcontextforwardsrequestsfromitsstoitsStrategy模式(四FamiliesofrelatedAnalternativetoStrategieseliminateconditionalsmustbeawareofdifferentCommunicationoverheadbetweenStrategyandIncreasednumberofDefiningtheStrategyandContextStrategiesastemteMakingStrategyobjectsStrategy模Strategy模式(五flyweight：考虑用flyweight模式来实现strategy

16：Visitor(一Representanoperationtobeperformedontheelementsofanobjectstructure.Visitorletsyoudefineanewoperationwithoutchangingtheclassesoftheelementsonwhichit 不 不 piler例 TypeCheckGenerateCodePrettyPrintVariableRefNodeAssignmentNodeVisitVariableRefVisitAssignmentVisitVa