10个经典设计模式定义及图解

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1、《10个经典设计模式——定义及图解》1、TheStrategyPatterndefinesafamilyofalgorithms,encapsulateseachone,andmakestheminterchangeable.Strategyletsthealgorithmvaryindependentlyfromclientsthatuseit.2、TheObserverPatterndefinesaone-to-manyrelationshipbetweenobjectssothatwhenoneobjectcha

2、ngesstate,allofitsdependentsarenotifiedandupdatedautomatically.Eachsubjectcanhavemanyobserversupdate()willbecalledwhentheSubject’sstatechanges.ThesemethodswillbecalledWhentoregisterasobservers,removethemselvesfromBeingobservers,orupdatealltheobserverswheneversta

3、techanges.Forexample：第9页（共9页）3、TheDecoratorPatternattachesadditionalresponsibilitiestoanobjectdynamically.Decoratorsprovideaflexiblealternativetosubclassingforextendingfunctionality.Forexample:第9页（共9页）4、TheFactoryMethodPatterndefinesaninterfaceforcreatinganobjec

4、t,butletssubclassesdecidewhichclasstoinstantiate.FactoryMethodletsaclassdeferinstantiationtosubclasses.Forexample:第9页（共9页）5、TheSingletonPatternensuresaclasshasonlyoneinstance,andprovidesaglobalpointofaccesstoit.HoldsouroneandonlyinstanceofSingleton.Youcanconveni

5、entlyaccessthemethodanywhere?6、TheCommandPatternencapsulatesarequestasanobject,therebylettingyouparameterizeotherobjectswithdifferentrequests,queueorlogrequests,andsupportundoableoperations.第9页（共9页）publicvoidexecute(){receiver.action();}Forexample:7、TheAdapterPa

6、tternconvertstheinterfaceofaclassintoanotherinterfacetheclientsexpect.Adapterletsclassesworktogetherthatcouldn’totherwisebecauseofincompatibleinterfaces.第9页（共9页）Forexample:8、TheFacadePatternprovidesaunifiedinterfacetoasetofinterfacesinasubsystem.Façadedefinesahi

7、gher-levelinterfacethatmakesthesubsystemeasiertouse.第9页（共9页）Forexample:9、TheTemplateMethodPatterndefinestheskeletonofaalgorithminamethod,deferringsomestepstosubclasses.TemplateMethodletssubclassesredefinecertainstepsofanalgorithmwithoutchangingthealgorithm’sstru

8、cture.第9页（共9页）primitiveOperation1();primitiveOperation2();Forexample:10、TheStatePatternallowsanobjecttoalteritsbehaviorwhenitsinternalstatechanges.第9页（共9页）state.handl