面向对象系统分析与设计_单例模式.ppt

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1、29八月2021NeusoftComputerScienceandTechnologyDepartmentcopyright1OOSystemAnalysis&Design【SingletonPattern】29八月2021NeusoftComputerScienceandTechnologyDepartmentcopyright2Enjoychocolate…29八月2021NeusoftComputerScienceandTechnologyDepartmentcopyright3Ourjobis:Todesignachocolateboiler,whichcouldmak

2、eachocolatebars.29八月2021NeusoftComputerScienceandTechnologyDepartmentcopyright4Therulesofchocolateboiler:Tofilltheboileritmustbeempty;Todraintheboileritmustbefullandalsoboiled.Toboiltheboileritmustbefullandnotalreadyboiled.29八月2021NeusoftComputerScienceandTechnologyDepartmentcopyright5Howtod

3、esigntheclass?properties?methodbody?29八月2021NeusoftComputerScienceandTechnologyDepartmentcopyright6Aclassdiagram:29八月2021NeusoftComputerScienceandTechnologyDepartmentcopyright7Question:CanyouimprovetheChocolateBoilerclassintowhichonlyoneinstanceofChocalateBoileriscreatedinanapplication?29八月2

4、021NeusoftComputerScienceandTechnologyDepartmentcopyright8TheSingletonPatternTheSingletonPatternensuresaclasshasonlyoneinstance,andprovidesaglobalpointofaccesstoit.29八月2021NeusoftComputerScienceandTechnologyDepartmentcopyright9Classdiagram:FactoryMethodHoldsouroneandonlyinstanceofSingleton.Y

5、oucanconvenientlyaccessthemethodanywhere?29八月2021NeusoftComputerScienceandTechnologyDepartmentcopyright10ClassisoverCongratulations!