面向?qū)ο蠓治龊驮O(shè)計講座8設(shè)計與代碼映射課件

第8講設(shè)計與代碼映射第8講設(shè)計與代碼映射內(nèi)容可見性設(shè)計類圖代碼映射測試驅(qū)動開發(fā)與代碼重構(gòu)9/4/20232內(nèi)容可見性8/3/202321.對可見性進行設(shè)計1.對可見性進行設(shè)計1.1目標確定四種可見性對設(shè)置可見性進行設(shè)計9/4/202341.1目標確定四種可見性8/3/202341.2可見性可見性Visibility是對象看到或引用其它對象的能力為了使發(fā)送者對象能夠向接收者對象發(fā)送消息，發(fā)送者必須具有接收者的可見性，即發(fā)送者必須擁有對接收者對象的某種引用或指針9/4/202351.2可見性可見性Visibility是對象看到或引用其它:RegisterenterItem(itemID,quantity):ProductCatalogspec:=getSpecification(itemID){publicvoidenterItem(itemID,qty){...spec=catalog.getSpecification(itemID)...}}classRegister{...

privateProductCatalogcatalog;...}9/4/20236:RegisterenterItem(itemID,qu1.3四種可見性實現(xiàn)對象A到對象B的可見性通常有四種方式:屬性可見性AttributeVisibility:B是A的屬性參數(shù)可見性Parametervisibility:B是A方法中的參數(shù)局部可見性LocalVisibility:B是A中方法的局部對象（不是參數(shù)）全局可見性GlobalVisibility:B具有某種方式的全局可見性為了使對象A能夠向?qū)ο驜發(fā)送消息，對于A而言，B必須是可見的9/4/202371.3四種可見性實現(xiàn)對象A到對象B的可見性通常有四種方式:8(1)屬性可見性這是一種相對持久地可見性:RegisterenterItem(itemID,quantity):ProductCatalogspec:=getSpecification(itemID){publicvoidenterItem(itemID,qty){...spec=catalog.getSpecification(itemID)...}}classRegister{...

privateProductCatalogcatalog;...}9/4/20238(1)屬性可見性這是一種相對持久地可見性:Register(2)參數(shù)可見性這是一種相對暫時的可見性2:makeLineItem(spec,qty)enterItem(id,qty)1:spec:=getSpecification(id)2.1:create(spec,qty):Register:Sale:ProductCatalogsl:SalesLineItem{makeLineItem(ProductSpecification

spec,intqty){...sl=newSalesLineItem(spec,qty);...}}9/4/20239(2)參數(shù)可見性這是一種相對暫時的可見性2:makeLin將參數(shù)可見性轉(zhuǎn)化為屬性可見性十分常見2:makeLineItem(spec,qty)enterItem(id,qty)2:spec:=getSpecification(id)2.1:create(spec,qty):Register:Sale:ProductCatalogsl:SalesLineItem//initializingmethod(e.g.,aJavaconstructor){SalesLineItem(ProductSpecificationspec,intqty){...productSpec=spec;//parametertoattributevisibility...}}9/4/202310將參數(shù)可見性轉(zhuǎn)化為屬性可見性十分常見2:makeLineI(3)局部可見性實現(xiàn)局部可見性的兩種常見方式:創(chuàng)建新的局部實例并將其分配給局部變量將方法調(diào)用返回的對象分配給局部變量:RegisterenterItem(itemID,quantity):ProductCatalogspec:=getSpecification(itemID){enterItem(id,qty){...//localvisibilityviaassignmentofreturningobjectProductSpecificationspec=catalog.getSpecification(id);...}}9/4/202311(3)局部可見性實現(xiàn)局部可見性的兩種常見方式::Regis(4)全局可見性這是一種相對持久的可見性將實例分配給全局變量，這在某些語言如C++中是可能的9/4/202312(4)全局可見性這是一種相對持久的可見性8/3/2023121.4采用UML表示可見性:A:B1:msg():C2:msg():D3:msg()<<association>><<parameter>><<local>>:E4:msg()<<global>><<association>>isusedforattributevisibility9/4/2023131.4采用UML表示可見性:A:B1:msg():C2:2.生成設(shè)計類圖2.生成設(shè)計類圖2.1引言交互圖完成后，有可能來定義軟件類（接口）的描述設(shè)計類圖（DesignClassDiagrams，DCD)9/4/2023152.1引言交互圖完成后，有可能來定義軟件類（接口）的描述8/2.2何時生成DCD實踐中，交互圖經(jīng)常與DCD并行創(chuàng)建為了更清楚地說明DCD，我們選擇了在交互圖之后介紹DCD9/4/2023162.2何時生成DCD實踐中，交互圖經(jīng)常與DCD并行創(chuàng)建8/32.3DCD例子RegisterenterItem(...)SaledateisComplete:BooleantimemakeLineItem(...)CapturesNavigability11Threesectionboxforclassdefinition.methods;thereareparameters,butunspecifiedtypeinformation9/4/2023172.3DCD例子RegisterenterItem(...)2.4DCD和UP術(shù)語設(shè)計類圖描述了應(yīng)用中的軟件類和接口類，關(guān)聯(lián)和屬性接口，包括操作和常量方法屬性類型信息可見性依賴UP并沒有專門的“設(shè)計類圖”UP定義了設(shè)計模型，包括交互，包和類圖.在UP設(shè)計模型中的類圖包含“設(shè)計類”9/4/2023182.4DCD和UP術(shù)語設(shè)計類圖描述了應(yīng)用中的軟件類和2.5領(lǐng)域模型vs.設(shè)計模型類Register...endSale()enterItem(...)makePayment(...)SaledateisComplete:BooleantimemakeLineItem(...)CapturesRegisterSaledateisComplete:BooleantimeCapturessoftwareclass1111DomainModelDesignModelConcept;conceptualclass9/4/2023192.5領(lǐng)域模型vs.設(shè)計模型類Register...en2.6創(chuàng)建NextGenPOSDCD確定軟件類并展示它們檢查交互圖并列出提到的所有類RegisterSaleProductCatalogProductSpecificationStoreSalesLineItemPayment9/4/2023202.6創(chuàng)建NextGenPOSDCD確定軟件類并展示它們給這些類畫類圖，列出通過領(lǐng)域模型中識別出來，并在設(shè)計中采用的屬性TheCashierisnotpresentinthedesignsinceforthecurrentiterationitisnotnecessarytomodelitinsoftware.9/4/202321給這些類畫類圖，列出通過領(lǐng)域模型中識別出來，并在設(shè)計中采用的添加方法名通過分析交互圖，每一個類具有的方法可以確定:Register:Sale2:makeLineItem(spec,qty)Sale...makeLineItem(...)9/4/202322添加方法名:Register:Sale2:makeLineSalesLineItem-quantity+getSubtotal()ProductCatalog...+getSpecification(...)ProductSpecification-description-price-itemID...Store-address-name+addSale(...)Payment-amount...Register...+endSale()+enterItem(...)+makeNewSale()+makePayment(...)Sale-date-isComplete-time+becomeComplete()+makeLineItem(...)+makePayment(...)+getTotal()9/4/202323SalesLineItem-quantity+getSu2.7方法的命名一些注意點create消息的解釋訪問方法多對象消息與語言無關(guān)的語法9/4/2023242.7方法的命名一些注意點8/3/202324（1）方法名-create每一種語言有各自特定的實例化instantiation或者初始化initialization的方法在C++,它包含了通過跟隨一個構(gòu)造函數(shù)的new操作進行自動內(nèi)存分配在Java中,它包含了對new運算符的調(diào)用，后面跟構(gòu)造函數(shù)調(diào)用9/4/202325（1）方法名-create每一種語言有各自特定的實例化ins（2）Accessing方法獲取或者設(shè)置屬性我們可以將所有屬性定義為私有，并對它們定義accessor和mutator這些方法一般在類圖中不顯示-9/4/202326（2）Accessing方法獲取或者設(shè)置屬性8/3/202（3）多對象給多對象的消息一般解釋為發(fā)送給一個container/collection對象，例如JavaMap,aC++map或者SmalltalkDictionary1:spec:=getSpecification(id)1.1:spec:=find(id):ProductCatalog:ProductSpecificationThefindmessageistothecontainerobject,nottoaProductSpecification.9/4/202327（3）多對象給多對象的消息一般解釋為發(fā)送給一個contain2.8增加更多的類型信息屬性，方法參數(shù)和返回值的類型可以有選擇的顯示什么時候顯示?取決于目的:CodeGenerationoronlyRead9/4/2023282.8增加更多的類型信息屬性，方法參數(shù)和返回值的類型可以有選SalesLineItemquantity:IntegergetSubtotal():MoneyProductCatalog...getSpecification(id:ItemID):ProductSpecificationProductSpecificationdescription:Textprice:MoneyitemID:ItemID...Storeaddress:Addressname:TextaddSale(s:Sale)Paymentamount:Money...Register...endSale()enterItem(id:ItemID,qty:Integer)makeNewSale()makePayment(cashTendered:Money)Saledate:DateisComplete:Booleantime:TimebecomeComplete()makeLineItem(spec:ProdSpecification,qty:Integer)makePayment(cashTendered:Money)getTotal():MoneyReturntypeofmethodvoid;noreturnvalue9/4/202329SalesLineItemquantity:Intege2.9添加關(guān)聯(lián)和方向關(guān)聯(lián)的每一端稱為一個角色，在DCD中，角色可以用方向箭頭修飾9/4/2023302.9添加關(guān)聯(lián)和方向關(guān)聯(lián)的每一端稱為一個角色，在DCD中，角CapturesRegistercurrentSale:SaleendSale()enterItem(...)makeNewSale()makePayment(...)SaledateisCompletetimebecomeComplete()makeLineItem(...)makePayment(...)getTotal()NavigabilityarrowindicatesRegisterobjectsareconnecteduni-directionallytoSaleobjects.AbsenceofnavigabilityarrowindicatesnoconnectionfromSaletoRegister.RegisterclasswillhaveanattributepointingtoaSaleobject.11thecurrentSaleattributeisoftenexcluded,asitisimpliedbythenavigableassociationfromRegistertoSale.9/4/202331CapturesRegistercurrentSale:關(guān)聯(lián)上的方向箭頭一般解釋為從源到目標類的屬性可見性在OOP中,它一般被實現(xiàn)為源類中有一個指向目標類對象的屬性9/4/202332關(guān)聯(lián)上的方向箭頭一般解釋為從源到目標類的屬性可見性8/3/2一些需要定義從A指向B的方向性修飾的情形:A發(fā)送消息給BA創(chuàng)建B的實例A需要保持與B的連接9/4/202333一些需要定義從A指向B的方向性修飾的情形:8/3/20233方向性Navigability通過交互圖來識別i:Store:Registerpc:ProductCatalogcreate()2:create(pc)1:create()1.2:loadProdSpecs():ProductSpecification1.1:create()1.2.2*:add(ps)1.2.1*:create(id,price,description)ps:ProductSpecification9/4/202334方向性Navigability通過交互圖來識別i:StorSalesLineItemquantity:IntegergetSubtotal()ProductCatalog...getSpecification(...)ProductSpecificationdescription:Textprice:MoneyitemID:ItemID...Storeaddress:Addressname:TextaddSale(...)Paymentamount:Money...Contains1..*Contains1..*RegisterendSale()enterItem(...)makeNewSale()makePayment(...)Saledate:DateisComplete:Booleantime:TimebecomeComplete()makeLineItem(...)makePayment(...)getTotal()CapturesHousesUsesLooks-inPaid-byDescribes1111111111111*Logs-completed4*19/4/202335SalesLineItemquantity:Intege2.10添加依賴關(guān)系依賴關(guān)系表明一個元素（包括類，用例，等等）知道另外一個元素用虛線箭頭表示在類圖中，依賴關(guān)系可以表示非屬性可見性，即：參數(shù)，全局或者局部可見性9/4/2023362.10添加依賴關(guān)系依賴關(guān)系表明一個元素（包括類，用例，等SalesLineItemquantity:IntegergetSubtotal()ProductCatalog...getSpecification(...)ProductSpecificationdescription:Textprice:MoneyitemID:ItemID...Storeaddress:Addressname:TextaddSale(...)Paymentamount:Money...Contains1..*Contains1..*Register...endSale()enterItem(...)makeNewSale()makePayment(...)Saledate:DateisComplete:Booleantime:TimebecomeComplete()makeLineItem(...)makePayment(...)getTotal()CapturesHousesUsesLooks-inPaid-byDescribes1111111111111*AdependencyofRegisterknowingaboutProductSpecification.Recommendedwhenthereisparameter,globalorlocallydeclaredvisibility.Logs-completed4*19/4/202337SalesLineItemquantity:Intege成員細節(jié)的表示SampleClassclassAttribute+publicAttribute-privateAttributeattributeWithVisibilityUnspecifiedattribute1:typeburgers:ListofVeggieBurgerattribute2:type=initialvaluefinalConstantAttribute:int=5{frozen}/derivedAttributeclassMethod()+玞onstructor?SampleClass(int)methodWithVisibilityUnspecified()methodReturnsSomething():FooabstractMethod()abstractMethod2(){abstract}//alternate+publicMethod()-privateMethod()#protectedMethod()~packageVisibleMethod()finalMethod(){leaf}methodWithoutSideEffects(){query}synchronizedMethod(){guarded}method1WithParms(inparm1:String,inoutparm2:int)method2WithParms(parm1:String,parm2:float)method3WithParms(parm1,parm2)method4WithParms(String,int)methodWithParmsAndReturn(parm1:String):FoomethodWithParmsButUnspecified(...):FoomethodWithParmsAndReturnBothUnspecified()java.awt.Fontplain:Integer=0{frozen}bold:Integer=1{frozen}name:Stringstyle:Integer=0...+getFont(name:String):Font+getName():String...java.awt.Toolkitorjava.awt.Toolkit{abstract}...//thereareattributes,butnotshown#createButton(target:Button):ButtonPeer+getColorModel():ColorModel...FinalClass{leaf}...//therearemethods,butnotshown玦nterface粆Runnablerun()AlarmClockrun()...anemptycompartmentwithoutellipsismeansthereisdefinitelynomembers(inthiscase,noattributes)9/4/202338成員細節(jié)的表示SampleClassclassAttribuDCD中方法體的表示Register...endSale()enterItem(id,qty)makeNewSale()makePayment(cashTendered){ProductSpecificationspec=catalog.getSpecification(id);sale.makeLineItem(spec,qty);}{publicvoidenterItem(id,qty){ProductSpecificationspec=catalog.getSpecification(id);sale.makeLineItem(spec,qty);}}UMLnotation:AmethodbodyimplementationmaybeshowninaUMLnotebox.Itshouldbeplacedwithinbraces,whichsignifiesitissemanticinfluence(itismorethanjustacomment).Thesynaxmaybepseudo-code,oranylanguage.Itiscommontoexcludethemethodsignature(publicvoid...),butitislegaltoincludeit.9/4/202339DCD中方法體的表示Register...endSale()9/4/2023408/3/2023403.將設(shè)計映射為代碼3.將設(shè)計映射為代碼3.1簡介交互圖和DCD可以作為代碼生成過程的輸入實現(xiàn)模型包括源代碼，數(shù)據(jù)庫定義，源代碼，JSP/XML/HTML9/4/2023423.1簡介交互圖和DCD可以作為代碼生成過程的輸入8/3/23.2編程和開發(fā)過程現(xiàn)代方法:Design-while-programming但是我們經(jīng)常在編程前進行可視化建模9/4/2023433.2編程和開發(fā)過程現(xiàn)代方法:Design-while-3.3在實現(xiàn)時候的創(chuàng)造性和變更設(shè)計中也包括決策和創(chuàng)新工作代碼的生成=機械翻譯過程?不完全對需要修改，詳細的問題將出現(xiàn)并被解決9/4/2023443.3在實現(xiàn)時候的創(chuàng)造性和變更設(shè)計中也包括決策和創(chuàng)新工作8/3.4代碼變更和迭代過程9/4/2023453.4代碼變更和迭代過程8/3/2023453.5從DCD創(chuàng)建類的定義3.5從DCD創(chuàng)建類的定義定義帶有方法和簡單屬性的類publicclassSalesLineItem{privateintquantity;publicSalesLineItem(ProductSpecificationspec,intqty){...}publicMoneygetSubtotal(){...}}SalesLineItemquantity:IntegergetSubtotal():MoneyProductSpecificationdescription:Textprice:MoneyitemID:ItemID...Described-by1*Itisderivedfromthecreate(spec,qty)messagesenttoaSalesLineItem9/4/202347定義帶有方法和簡單屬性的類publicclassSale增加引用屬性類的引用屬性是依據(jù)類圖中的關(guān)聯(lián)和方向性來的SalesLineItemquantity:IntegergetSubtotal():MoneyProductSpecificationdescription:Textprice:MoneyitemID:ItemID...Described-bypublicclassSalesLineItem{privateintquantity;privateProductSpecificationproductSpec;publicSalesLineItem(ProductSpecificationspec,intqty){...}publicMoneygetSubtotal(){...}}*1SimpleattributeReferenceattribute9/4/202348增加引用屬性類的引用屬性是依據(jù)類圖中的關(guān)聯(lián)和方向性來的Sal引用屬性和角色名字角色名字是角色的標識SalesLineItemquantity:IntegergetSubtotal():MoneyProductSpecificationdescription:Textprice:MoneyitemID:ItemID...Described-bypublicclassSalesLineItem{...privateintquantity;privateProductSpecificationproductSpec;}productSpecRolenameusedinattributename.*19/4/202349引用屬性和角色名字角色名字是角色的標識SalesLineIt屬性映射Saledate:DateisComplete:Booleantime:TimebecomeComplete()makeLineItem()makePayment()getTtotal()publicclassSale{privateDatedateTime=newDate();...}InJava,thejava.util.Dateclasscombinesbothdateandtimestampinformation.Therefore,theseparateattributesinthedesigncanbecollapsedwhenmappingtoJava.9/4/202350屬性映射Saledate:DateisComplete3.6從交互圖中創(chuàng)建方法消息的順序被翻譯成方法定義中的一系列聲明2:makeLineItem(spec,qty)enterItem(id,qty)1:spec:=getSpecification(id)2.1:create(spec,qty)1.1:spec:=find(id):Register:Sale:ProductCatalogsl:SalesLineItemSalesLineItem:SalesLineItem:ProductSpecification2.2:add(sl)9/4/2023513.6從交互圖中創(chuàng)建方法消息的順序被翻譯成方法定義中的一系列Pro