《计算机专业英语》课件第28章

Component-BasedDevelopment—ARevolutioninApplicationDevelopment

Component-BasedDevelopment(CBD)willrevolutionizethesoftwareindustry.1Unlikerecenttrendssuchasobjectsandclient/server,itisnotjustanotherflavorofdistributedcomputing,butanextensiblearchitecturetosupportalllifecyclecomputingmetaphor,includingdesign,developmentanddeployment.

Becauseofitshighlevelsofreuseandinteroperability,CBDwillinfluenceeverydimensionofapplicationcomposition,includingalltypesofclients,applicationserversanddatabasesevers,andwillhaveaprofoundimpactonallaspectsofapplicationdevelopment.

CBD’spredecessorwasobjectoriented(OO)development.Objectsweretheindustry’sfirststabatdeliveringhighlevelsofreuse.2ButtheunsophisticatednatureofOOdevelopmentenvironmentsandthelackofacommoninfrastructureforaddressingobjectinteroperabilityhinderedtheirmainstreamadoption.3OOdevelopmentwastoofaraheadofitstimeandlackedinfrastruturalsupportfromthesoftwareindustry.

CBDredefinesobjectsinthecontextofastandardizedinfrastructureforinteroperabilityframeworksfortheconstructionandassemblyofapplications,andprebuiltcomponentsthatsubscribetocomponentinfrastructuresandframeworks.TheinfrastructuraldimensionofthecomponentarchitectureisthecatalysttoachievingthereuseandinteroperabilitythatunderminedOOdevelopment.4Thisinfrastructure,alongwiththeavailabilityCBDframeworksthatenablecomponentdesign,constructionandassembly(ratherthanjustbeinganenvironmentforvisualprogramming),willforeverchangehowapplicationsaredeveloped.

Theevolutionisfromfirst-generation(2-tier)andsecondgeneration(3-tier)client/servertoCBD.

Becausenewerphasessuchas3tierclient/serverandCBDessentiallysubsumethefunctionalityofolderones,themigrationofsystemistheoreticallypossible,althoughtypicallyitisdifficultduetotheproprietaryconstructsofearlierproducts.Asaresult,manyapplicationsbuiltwitholderproductssimplybecomeanotherclassoflegacysystem.

CBDcanbedividedintothreestages:monolithic,distributedandpersistentovertime,certainstandardswillbecomepervasive,coreserviceswillbecomecommercial,andtheinfrastructuraldimensionofCBDwillensurethatportabilityandinteroperabilityrequirementsaremet.Componentframeworksplayakeyroleindefiningthedesign,developmentanddeploymentparadigm,usagemetaphor,infrastucturalextensionsandprebuiltcomponentsforapplicationdevelopment.Frameworks,whichworkwiththecomponentinfrastructuretoprovideacompletedevelopmentenvironment,arethemostimportantdimension

ofCBD.

ThefirststageofCBDistheeraofmonolithiccomponents,aseemingoxymoronthatdescribestheadolescentstateofcomponentstoday.5Noneoftoday’scomponentstandardsandframeworkshaveresolvedtheportabilityandinteroperabilityissuesthatwouldallowcomponentstobedistributedorpersistentacrossmultiplevendorframeworks,standardsforCBDarebeingestablishedbutstandardizedinfrastructuralcomponentsdonotexist.6Asaresult,frameworksarebeingintroducedwithahighcontentlevelofproprietary

infrastructuralcomponents.NewWords

revolutionizev.使……发生革命extensibleadj.广泛的metaphorn.理念reusev.重新使用interoperabilityn.互用性dimensionn.方面compositionn.构成profoundadj.深刻的predecessorn.前身orientedadj.导向的hinderv.阻碍adoptionn.采用redefinev.重新定义assemblyn.集合,装配subscribev.赞成catalystn.催化剂subsumev.包含,包容functionalityn.功能性theoreticallyadv.理论上地monolithicn.单片电路pervasivev.普遍深入的portabilityn.可携带,轻便paradigmv.范例eran.时期persistentadj.一贯的,持续的PhrasesandExpressions

becauseof因为haveanimpacton对……有影响beaheadof在……之前not...but不是……而是alongwith连同ratherthan而不是dueto由于asaresult因此TheExplanationofDifficultStatements

1.Unlikerecenttrendssuchasobjectsandclient/server,it’snotjustanotherfavorofdistributedcompany,butanextensivearchitecturetosupportalifecyclecomputingmetaphor,includingdesign,developmentanddeployment.

分析:“Unlikerecenttrendssuchasobjectsandclient/server”为介词短语,在句中作状语;主句“not...but”译为“不是……而是”。

句意:与诸如(面向)对象和客户机/服务器等最新趋势不同,CBO不只是一种分布计算新花样,而是一种广泛的体系结构,支持整个生命周期计算的理念,包括设计、开发和发布。

2.ButtheunsophisticatednatureofOOdevelopmentenvironmentsandthelackofacommoninfrastructureforaddressingobjectinteroperabilityhinderedtheirmainsteamadoption.

分析:此句中主语部分较长,给翻译造成了一定的难度。翻译时可采用“转译法”和“分译法”。

句意:但是OO开发环境本质不够完善,缺乏解决对象互用性的公共基础设施,这些因素防害了它们成为主流产品。

2.ButtheunsophisticatednatureofOOdevelopmentenvironmentsandthelackofacommoninfrastructureforaddressingobjectinteroperabilityhinderedtheirmainsteamadoption.

分析:

此句中主语部分较长,给翻译造成了一定的难度。翻译时可采用“转译法”和“分译法”。

句意:

但是OO开发环境本质不够完善,缺乏解决对象互用性的公共基础设施,这些因素防害了它们成为主流产品。

4.Thisinfrastructure,alongwiththeavailabilityofCBDframeworksthatenablecomponentdesign,constructionandassembly(ratherthanjustbeinganenvironmentforvisualprogramming),willforeverchangehowapplicationsaredevelopment.

分析:此句的主语部分亦较长,其中“介词alongwith+名词”不影响句中主语与谓语动词的一致关系。例如:Thismanalongwithhissonsalwayscatchesthelargefish.

句意:这种基础设施加上CBD架构的可获得性将永远改变应用程序的开发,而CBD架构能实现组件的设计、编制和装配(不只是一种直观编程的环境)。

5.Noneoftoday’scomponentstandardsandframeworkshaveresolvedtheportabilityandinteroperabilityissuesthatwouldallowcomponentstobedistributedorpersistent

acrossmultiplevendorframeworks.

分析:“noneof+名词”作主语时,谓语动词的单复数取决于介词of后面的名词的单复数。例如:

Noneoftheevidencepointstohisguilt.

Noneofourstudentswereinvolved.

句意:今天还没有一种组件标准和架构已经解决了可移植性和互用性的问题,而这些问题的解决将允许组件在多个厂商的架构上实现分布式或持续式。

6.Asaresult,frameworksarebeingintroducedwithahighcontentlevelofproprietaryinfrastructuralcomponents.

分析:“arebeingintroduced”为现在进行时的被动语态,例如:Theexperimentisbeingdonethisweek.

句意:因此,架构正在随着专有基础设施组件的高满意程度一起引入。GrammarTranslationSkills词类转译法

由于词的使用范围和表达方式不一样,原文中某词类的词,在译成汉语时不能“对号入座”,可以(有时必须)转为另一种词类,否则就难以清晰表达原文的意义,或者违背汉语的表达习惯。常见的几种转译的表达方式如下:

1.转译成汉语动词

汉语中使用动词比英语多,也比较灵活,有时一个短句就用了好几个动词。因此英语中名词、介词和副词均可转译为汉语动词。例如:

(1)Heisagoodobserver.他善于观察。

(2)Aftertheaccomplishmentofthepresenttask,therewillfollowamorearduousone.现在的任务完成后,还有更艰巨的任务。

(3)Atlast,hewhisperedahurriedgood-byetohishostanddartedtowardthedoor.最后,他赶紧向主人轻声道别,然后向门口跑去。

(4)Wecanseethestarsintheskyveryclearlywithatelescope.我们用一架望远镜就可以清楚地看到天空中的星星。

(5)Iopenedthewindowtoletthefreshairin.我打开窗户让新鲜空气进来。

2.转译成汉语名词

英语中有些动词的概念很难直接用汉语动词表现出来,这时可以转译成汉语的名词。例如:

(1)Theelectroniccomputerischaracterizedbyitsaccurateandcomputation.电脑的主要特征是计算又快又准。

(2)Energyiscommonlydefinedasthecapacityofasystemtodowork.能的一般定义是系统做功的能力。

(3)Heimpressedmefavorably.他给我很好的印象。

(4)Gasesdifferfromsolidsinthattheformerhavegreatercompressibilitythanthelatter.气体和固体的区别在于前者比后者有更大的可压缩性。

3.转译成汉语形容词

由于动词可转译成名词,原来修饰动词的副词也相应地转译成形容词。例如:

(1)Thiswaveguidetubeischieflycharacterizedbyitssimplicityofstructure.这种波导管的主要特点是结构简单。

(2)Heimpressedmedeeply.他给我留下了深刻的印象。

4.转译成汉语副词由于英语名词转译成汉语的动词,所以原来修饰名词的形容词自然就要译成汉语的副词。例如:

Wemustmakefulluseofexistingtechnicalequipment.我们必须充分地利用现有的技术设备。ExercisesⅠ.Fillintheblanksaccordingtothetext:(1)CBDwillinfluenceeverydimensionofapplicationcomposition,includingalltypesofclients,__________,andwillhaveaprofoundimpactonallaspectsofapplicationdevelopment.(2)CBD’spredecessorwas______________development.(3)The______________ofthecomponentarchitectureisthecatalysttoachievingthereuseandinteroperabilitythatunderminedOOdevelopment.(4)CBDcanbedividedintothreestages:______________.(5)______________,whichworkwiththecomponentinfrastructuretoprovideacompletedevelopmentenvironment,arethemostimportantdimensionofCBD.Ⅱ.Decidewhethereachofthefollowingstatementsistrueorfalseaccordingtothetext:(1)Component-BasedDevelopment(CBD)willrevolutionizethesoftwareindustry.(2)Component-BasedDevelopment(CBD)isjustanotherflavorofdistributedcomputing.(3)Objectsweretheindustry’ssecondstabatdeliveringhighlevelsofreuse.(4)Theevolutionisfromfirst-generation(-tier)andsecondgeneration(3-tier)client/servertoCBD.(5)ThethirdstageofCBDistheeraofmonolithiccomponents,aseemingoxymoronthatdescribestheadolescentstateofcomponentstoday.Ⅲ.TranslatethefollowingsentencesintoChinese:(1)Hismusicwasanexcitingmixtureofcountrymusicandtheblues.(2)Ifoundhimathisbookinthelibrary.(3)Thebookaimsatgivingageneraloutlineofthesubject.(4)Wewerewronglyinformed.(5)ThemanIsawatthepartylookedandtalkedlikeanAmerican.Ⅳ.TranslatethefollowingparagraphintoChinese:

ThepersistentcomponentstageoccurswhenvirtuallyalltheinfrastructureassociatedwithCBDiscommercialized.Commercializationencouragesthegrowthofserviceproviderswhobrokermanytypesofcomponents,whichareeasilycustomizedbybusinessrules.Thiselevatestheconceptofleasinginthesoftwaremarket;inthisstage,mostcomponentsarereused,leasedorpurchasedbyconsumers.ComponentsignisthefocalpointofCBDactivitiesforthosethatmanufacturecomponents.Toolcentricissues(lifecyclecoverage,developmentparadigm,usagemetaphorandavailabilityofprebuiltcomponents)becomekeyproductdifferences.ReadingMaterialsComponent-BasedDevelopment-ARevolutioninApplicationDevelopment

Inthenextstage,monolithiccomponentsgivewaytodistributedcomponentsmaturingcomponentstandardsandnewinfrastructuralcomponentspermitcomponentinteroperabilityandportability.Frameworks,nowfreedofspecificinfrastructuraltasks,focusmoreonthedevelopmentparadigmandsupportmoreaspectsofcomponentlifecycle.Theincreasedrichnessofcomponentstandardsandframeworksbringssupportformoregranularcomponents,withmanyvendorsmarketingcomponentlibraries.Inthisstage,thescopeofCBDexpandstoincludecomponentdesign.ComponentbaseddesignchangestheCBDparadigmfromphysicalconstructionlogicaldesign.Theincreasedgranularityofcomponents,theirrichandvariedsupply,andtheinclusionofdesignmetadatainthecomponentsthemselvesimprovesCBDandvalidatesitastheapplicationdevelopmentparadigm.

ThepersistentcomponentstageoccurswhenvirtuallyalltheinfrastructureassociatedwithCBDiscommercialized.Commercializationencouragesthegrowthofserviceproviderswhobrokermanytypesofcomponents,whichareeasilycustomizedbybusinessrules.Thiselevatestheconceptofleasinginthesoftwaremarket;inthisstage,mostcomponentsarereused,leasedorpurchasedbyconsumers.ComponentsignisthefocalpointofCBDactivitiesforthosethatmanufacturecomponents.Tool-centricissues(lifecyclecoverage,developmentparadigm,usagemetaphorandavailabilityofprebuiltcomponents)becomekeyproductdifferences.

Now,applicationquality—measurableforthefirsttimebecomesacompetitivefeature.Frameworkscontinueasthefocalpointforenablingapplicationdevelopmentduetothecontroloverthedevelopmentparadigm.Oldfunctionalitymoves“down”andmayevenbecomepartoftheoperatingsystem.Newfunctionalityisdividedintoprocessfunctionality,whichresidesintheframeworks,anddomainspecificfunctionality(alongwithdomaincontent,whichisembodiedincomponentlibraries).Thepersistentcomponentphaseismarkedbycross-vendorinteroperabilitywithouttherequirementforspecificbilateraltechnologyrelationships.

Thisdistributedcomputingmodel,whichreliesonasynergisticrelationshipbetweencomponentstandards,infrastructureandframeworks,operatesmostefficientlywhenvendorscollaborateonthecoreinfrastructuraldimensionsofCBD.Thefasterthiscollaborationoccurs,thefasterCBDwillmature.SuchcollaborationimpliesagreementonAPIs,corelanguages,foundationclasse