创建型设计模式培训英文课件

BryanLi6/18/2007,Agenda,OODesignPrincipleOCP(Open-ClosedPrinciple)LSP(LiskovSubstitutionPrinciple)SRP(singleresponsibilityPrinciple)DIP(DependenceInversionPrinciple)ISP(InterfaceSegregationPrinciple)CARP(Composite/AggregateReusePrinciple)LoD(LasodDemeterLeastKnowledgePrinciple-LKP)DesignPatternCreationalPatternStructuralPatternBehavioralPattern,Agenda,CreationalPatternFactoryPatternSimpleFactoryFactoryMethodAbstractFactory,FactoryPattern,SimpleFactorySimplymovedthecodethatisusedtocreateobjecttoanewclassCreator.,FactoryPattern,PizzaStoryYouwanttoopenapizzastore,Assumethatyouorganizelikethis:,SimplePattern,publicclassPizzaStorePizzaorderPizza(Stringtype)Pizzapizza=null;if(type.equals(chees)pizza=newCheesePizza();elseif(type.equals(greek)pizza=newGreekPizza();elseif(type.equals(pepperoni)pizza=newPepperoniPizza();pizza.prepare();pizza.bake();pizza.cut();pizza.box();returnpizza;,SimplePattern,Mendingdesignofpizzastory,SimplePattern,AddSimplePizzaFactoryClasspublicclassSimplePizzaFactorypublicstaticPizzacreatePizza(Stringtype)Pizzapizza=null;if(type.equals(chees)pizza=newCheesePizza();elseif(type.equals(greek)pizza=newGreekPizza();elseif(type.equals(pepperoni)pizza=newPepperoniPizza();returnpizza;,publicclassPizzaStoreSimplePizzaFactoryfactory;publicPizzaorderPizza(Stringtype)Pizzapizza=SimplePizzaFactory.createPizza(type);pizza.prepare();pizza.bake();pizza.cut();pizza.box();returnpizza;,SimplePattern,FeatureyoudontneedtoinstantiateanobjecttomakeuseofthecreatemethodyoucantcreatesublcassandchangethebehaviorofthecreatemethodNottypicaldesignpattern-moreofaprogrammingidiomFadeFormatMergeCreatorintoConcreteProduct,SimplePattern,AdvantageReusethecodethatcreateobjectDisadvantageIfproducthasanychange,Creatorclassshouldbeimpacted.OODesignPrincipleOCP:ifaddnewtypeofproduct,intheviewofclientandproduct,itconformtoOCP,butintheviewofFactoryCreator,itdoesnot.,FactoryMethod,Defineaninterfaceforcreatinganobject,butletssubclassesdecidewhichclasstoinstantiate.FactoryMethodletsaclassdeferinstantiationtosubclasses.,FactoryMethod,PizzaStoryBecauseyourpizzastorehasagoodbusiness,manypeoplewanttoopenyoursubstoreinNewYorkandChicago.Soyouwillthelocalizefavorproblem.Basedonsimplefactory,designlikethefollowing:,FactoryMethod,TheabovedesignsIssueBecausesimpelefactorygenerallyusestaticcreatemethod.Soifthereareseveralsimplefactorycreators,itwillimpactencapsulationofclientclass,thatisPizzaStore.publicclassPizzaStoreSimplePizzaFactoryfactory;publicPizzaorderPizza(Stringtype)Pizzapizza=SimplePizzaFactory.createPizza(type);/orNYPizzaFactory.createPizza(type);/orChicagoPizzaFactory.createPizza(type);pizza.prepare();pizza.bake();pizza.cut();pizza.box();returnpizza;,FactoryMethod,TheabovedesignsIssueifsimpelefactorygenerallyusenon-staticcreatemethodandotherfactoriesderivefromsimplePizzaFactory.SoWhat?,FactoryMethod,publicclassPizzaStoreSimplePizzaFactoryfactory;publicPizzaStore(SimplePizzaFactoryfactory)this.factory=factory;publicPizzaorderPizza(Stringtype)Pizzapizza=factory.createPizza(type);pizza.prepare();pizza.bake();pizza.cut();pizza.box();returnpizza;publicclassClientpublicstaticvoidmain(Stringargs)NYPizzaFactorynyfactory=newNYPizzaFactory();PizzaStorenyStore=newPizzaStore(nyfactory);nyStore.orderPizza(Veggie);,FactoryMethod,NewrequirementbringnewissueNowNewYorkpizzastoresprocedureofmakepizzawaschanged:theydbakethingsalittledifferently,theyneedntcutthepizzaandtheydusethird-partyboxes.Sowemusthavedifferentpizzastoreclassinordertosolvethisissue.,Addsubclass,FactoryMethod,RefactorthedesignNowthehierarchyofPizzastorecompletelyshowsthehierarchyofsimplefactory.Sonowtheseriesoffactoryclassareredundancy.WeshouldmovethemethodoffactoryintotheseriesclassesofPizzastore.Therefactoreddesignisasthebelow:,Client,FactoryMethod,Product,FactoryMethod,publicabstractclassPizzaStorepublicPizzaorderPizza(Stringtype)Pizzapizza=createPizza(type);doHandlePizza(pizza);returnpizza;protectedvoiddoHandlePizza(Pizzapizza)pizza.prepare();pizza.bake();pizza.cut();pizza.box();publicabstractPizzacreatePizza(Stringtype);,FactoryMethod,publicclassNYStylePizzaStoreextendsPizzaStorepublicPizzacreatePizza(Stringtype)Pizzapizza=null;if(type.equals(chees)pizza=newNYStyleCheesePizza();elseif(type.equals(greek)pizza=newNYStyleGreekPizza();elseif(type.equals(pepperoni)pizza=newNYStylePepperoniPizza();returnpizza;protectedvoiddoHandlePizza(Pizzapizza)pizza.prepare();pizza.bake();/pizza.cut();pizza.box();,FactoryMethod,publicclassChicagoStylePizzaStoreextendsPizzaStorepublicPizzacreatePizza(Stringtype)Pizzapizza=null;if(type.equals(chees)pizza=newChicagoStyleCheesePizza();elseif(type.equals(greek)pizza=newChicagoStyleGreekPizza();elseif(type.equals(pepperoni)pizza=newChicagoStylePepperoniPizza();returnpizza;,FactoryMethod,FeatureTheFactoryMethodletssubclassesdecidewhichclasstoinstantiate.Afactorymethodmaybeparameterized(ornot)toselectamongseveralvariationsofaproduct.FMdoesntcertainlyreturnnewobjectverytime.ButreturnedobjectmustbecreatedbyFMitself,butnotbepassedfromoutside.Returnedtypeshouldbeabstracttype,notconcretetype.,FactoryMethod,Advantagethecreator/clientclassiswrittenwithoutknowledgeoftheactualproductsthatwillbecreated;thatisclientsdecoupledfromtheconcrettypes.DisadvantageClientsmighthavetosubclasstheCreatorclassjusttocreateaparticularConcreteProductobject.WithOODesignPrincipleOCP:intheviewofclient/creator,itconformtoOCP,butintheviewofproduct,notcertainly.Ingeneral,inFMP,thereisaonlykindofproduct.Ifthereareseveralkinds,needparameterizedcreatemethodlikecreatePizzamethod.Soifaddproductkind,allclient/creatorwillbeimpacted.SonotobeyOCP.,AbstractFactory,Provideaninterfaceforcreatingfamiliesofrelatedordependentobjectswithoutspecifyingtheirconcreteclasses.,AbstractFactory,PizzastoryPizzafromdifferentplacehasdifferentingredients,PlumTomatoSauce,ThickCrustDough,MozzarellaCheese,FrozenPepperoni,NewYork,MarinaraSauce,ThinCrustDough,ReggianoCheese,FreshPepperoni,Chicago,AbstractFactory,Closecoupling,Over-deephierarchy,AbstractFactory,Pizzastorypartofclassdiagram,AbstractFactory,publicinterfacePizzavoidprepare();voidbake();voidcut();voidbox();publicabstractclassPepperoniPizzaimplementsPizzaprotectedDoughdough;protectedSaucesauce;protectedCheesecheese;protectedPepperonipepperoni;publicabstractvoidprepare();publicvoidbox()System.out.println(boxpepperonipizza.);publicvoidbake()System.out.println(bakepepperonipizza.);publicvoidcut()System.out.println(cutpepperonipizza.);,AbstractFactory,publicclassNYStylePepperoniPizzaextendsPepperoniPizzapublicvoidprepare()dough=newThickCrustDough();sauce=newPlumTomatoSauce();cheese=newMozzarellaCheese();pepperoni=newFrozenPepperoni();publicclassNYStyleCheesePizzaextendsCheesePizzapublicvoidprepare()dough=newThickCrustDough();sauce=newPlumTomatoSauce();cheese=newMozzarellaCheese();,publicclassNYPizzaIngredientFactorypublicDoughcreateDough()returnnewThickCrustDough();publicSaucecreateSauce()returnnewPlumTomatoSauce();publicCheesecreateCheese()returnnewMozzarellaCheese();publicPepperonicreatePepperoni()returnnewFrozenPepperoni();,AbstractFactory,Userefactor“extractinterface”togetPizzaIngredientFactoryinterfaceinNYPizzaIngredientFactoryclass.publicinterfacePizzaIngredientFactorypublicabstractDoughcreateDough();publicabstractSaucecreateSauce();publicabstractCheesecreateCheese();publicabstractPepperonicreatePepperoni();publicclassNYPizzaIngredientFactoryimplementsPizzaIngredientFactory.,publicclassNYPizzaIngredientFactorypublicDoughcreateDough()returnnewThickCrustDough();publicSaucecreateSauce()returnnewPlumTomatoSauce();publicCheesecreateCheese()returnnewMozzarellaCheese();publicPepperonicreatePepperoni()returnnewFrozenPepperoni();,AbstractFactory,publicclassChicagoStyleCheesePizzaextendsCheesePizzapublicvoidprepare()dough=newThinCrustDough();sauce=newMarinaraSauce();cheese=newReggianoCheese();publicclassNYStyleCheesePizzaextendsCheesePizzapublicvoidprepare()dough=newThickCrustDough();sauce=newPlumTomatoSauce();cheese=newMozzarellaCheese();,publicclassChicagoStyleCheesePizzaextendsCheesePizzaPizzaIngredientFactoryfactory;publicChicagoStyleCheesePizza()factory=newChicagoPizzaIngredientFactory();publicvoidprepare()dough=factory.createDough();sauce=factory.createSauce();cheese=factory.createCheese();publicclassNYStyleCheesePizzaextendsCheesePizzaPizzaIngredientFactoryfactory;publicNYStyleCheesePizza()factory=newNYPizzaIngredientFactory();publicvoidprepare()dough=factory.createDough();sauce=factory.createSauce();cheese=factory.createCheese();,AbstractFactory,Userefactor“pullup”torestractfactorypropertyandpreparemethodintocheesePizza.AndthenwecandeleteChicagoStyleCheesePizzaandNYStyleCheesePizzabecausecombinationofCheesePizzaandseriesofIngredientFactorywillgetthesetwofavorspizza.Inthesameway,wecandeleteChicagoStylePepperoniPizzaandNYStylePepperoniPizza.publicabstractclassCheesePizzaimplementsPizzaprotectedDoughdough;protectedSaucesauce;protectedCheesecheese;protectedPizzaIngredientFactoryfactory;publicCheesePizza(PizzaIngredientFactoryfactory)this.factory=factory;publicvoidprepare()dough=factory.createDough();sauce=factory.createSauce();cheese=factory.createCheese();publicvoidbox()publicvoidbake()publicvoidcut(),Abstra