體系結構-太君軟件架構

52=+載體與事物的適配復雜度準則3：設計重在結構，而不是外在表現(xiàn) 準則4：只有設計良好，底層設計才能良好Thebetterearlydesign,theeasierdetaileddesignwill設計的五個準；外部表現(xiàn)是對外表現(xiàn)的能力，外部表現(xiàn)是為了滿足職責結構則是為了完成的質量，通；4+1Logictheobjectmodelofthedesign(whenanoodesignmethodissystem posedintoasetof ions,takenobjectsorobject{Component,connector,viewer:End-considers:functionalrequirements(whatthesystemshouldprovideintermsofservicestoitsusers)Processtocapturetheconcurrencyandsynchronizationaspectsoftheprocess:agrouoftasksthatformanexecutableviewer:multiplelevelof ions,alogicalnetworkofprocessesatthehighestlevelDevelopmentView:basisofalineofproduct, todescribethestaticanizationofthesoftwareinitsdevelopmentrepresentedbymoduleandsubsystemviewer:ProgrammersandSoftwareconsiders:softwaremoduleanization(Hierarchyoflayers,softwaremanagement,reuse,constraintsoftools)PhysicalView:todescribethemapofthesoftwareontothehardwareandreflectsitsdistributedaspectmapthesoftwaretotheTopologyandviewer:Systemconsiders:Non-functionalreq.regardingtounderlyinghardware(avalibility,reliability(fault-tolerance),performance(throughput)andscalability)putitallviewer:allusersofotherviewsandconsider:systemconsistency,helparchitectduringthearchitecturehelpillustrateandvalidatetheOO協(xié)作與協(xié)作設計（理解What’sAnapplicationcanbebrokendownintoasetofmanydifferentEachsuchbehaviorisimplementedbyadistinctcollaborationbetweentheobjectsoftheEverycollaboration,nomatterhowsmallorlarge,alwaysimplementsabehavioroftheapplicationImagineanobject-orientedapplicationasanetworkofobjectsconnectedbyrelationships.Collaborationsarethepatternsofmessagesthatplaythroughthatnetworkinpursuitofaparticularbehavior.Thecollaborationisdistributedacrossthenetworkofobjects,andsodoesnotexistinanyoneplaceIdentifysystembehaviorfromuse-fromsoftwarearchitecturedesign(ModuleinterfaceandProcesscommunication)Designcollaboration(ofsystembehaviors:controlstructures):twoways:DispersedandDispersed:LogicsofasystembehaviorisspreadwidelythroughtheobjectsCentralized:OneextracontrollerrecordalllogicsofasystemControlStyles:Dispersed,Centralized,CentralizedEasytofindwherethedecisionareEasytoseehowdecisionaremadeandtoalterthedecision-makingControllersmay ebloated(large,complexandhardtounderstand,maintain,ControllermaytreatothercomponentsasdataIncreasecouplingdestroysinformationDelegatedControllerarecoupledtofewercomponents,reducingInformationishiddeneasiertodivideintoDelegatedcontrolisthepreferredcontrolDispersedhavingmanycomponentsholdinglittledataandhavingfewhardtounderstandtheflowofunabletodomuchontheirown,increasinghardtohidecohesionisusuallyfewmodularityprinciplescanbesatisfiedAvoidinteractiondesignswheremostmessagesinatefromasingleKeepcomponentMakesureoperationalresponsibilitiesarenotallassignedtojustafewMakesureoperationalresponsibilitiesareconsistentwithdatatasksinmulti-Havecomponentsdelegateasmanylow-leveltasksasAvoidinteractionsthatrequireeachcomponenttosendmanyOOGRASP模式（或其中之一）（理解GRASP,GeneralResponsibilityAssignmentSoftwarePattern.Thesearenot‘designpatterns’,ratherfundamentalprinciplesofobjectdesign.GRASPfocusononeofthemostaspectsofobjectdesign,assigningresponsibilitiestoclassesGRASPLowHighPureProtectedLowProblem:TosupportlowdependencyandincresedSolution:AssignresponsibilitiessothatcouplingremainsCouplingTypesHighProblem:TokeepcomplexitySolution:AssignresponsibilitiessothatcohesionremainsCohesionTypesProblem:Whatisthemostbasicprinciplebywhichresponsibilitiesareassignedinobject-orienteddesign?Solution:Assignaresponsibilitytotheclassthathastheinformationnecessarytofulfilltheresponsibility.MaintainencapsulationofinformationPromoteslowcouplingPromoteshighcohesiveCancauseaclass eexessivelyProblem:AssignresponsibilityforcreatinganewinstanceofsomeSolution:Determinewhichclassshouldcreateinstancesofaclassbasedontherelationshipbetweenpotentialcreatorclassesandtheclasstobeinstantiated.WhoisresponsibilitytocreateanBycreator,assignclassBresponsibilityofcreatinginstanceofclassABaggregatesABcontainsABrecordsinstancesofABcloselyusesABhastheinitializingdataforcreatingAwherethereisachoice,preferBaggregatesorcontainsAPromoteslowcouplingbymakinginstancesofaclassresponsibleforcreatingobjectstheyneedtoreferenceBycreatingtheobjectsthemselves,theyavoidbeingdependentonanotherclasstocreatetheobjectforthemProblem:ToassignresponsibilityforhandlingasystemeventSolution:Ifaprogramreceiveeventsfromexternalsourcesotherthanitsgraphicalinterface,addaneventclasstodecoupletheeventsource(s)fromtheobjectsthatactuallyhandletheevents.FourThebusinessoroverallanization(afac?adeTheoverall“system”(afac?adeAnanimatethinginthethatwouldperformthework(aroleAnartificialclass(PureFabricationrepresentingtheuse(ausecaseCaremoreabouttheresponsibilitiesandUsingacontrollerobjectkeepsexternaleventsourcesandinternaleventhandlersindependentofeachother’typeandbehaviorThecontrollerobjectscan ehighlycoupledanduncohesivewithmoreProblem:TohandlealternativesbasedonSolution:Whenalternatebehaviorsareselectedbasedonthetypeofanobject,usepolymorphicmethodcalltoselectthebehavior,ratherthanusingifstatementtotestthetype.PureProblem:TonotviolateHighCohesionandLowSolution:Assignahighlycohesivesetofresponsibilitiestoanartificialclassthatdoesnotrepresentanythingintheproblem,inordertosupporthighcohesion,lowcoupling,andreuse.Highcohesionissupportedbecauseresponsibilitiesarefactoredintoaclassthatonlyfocusesoyspecificsetofrelatedtasks.ReusepotentialmaybeincreasedofthepresenceoffinegrainedPureFabricationTypicalSeparatingrepresentationfromSeparatingplatforms(facilities)fromSeparatingcomplexSeparatingcomplexdataProblem:Toavoiddirectcoupling?Mainlybecausechangability!Tode-coupleobjectssothatLowcouplingissupportedandreusepotentialremainshigh?Solution:Assigntheresponsibilitytoanintermediateobjecttomediatebetweenothercomponentsorservices,sothattheyarenotdirectlycoupled.Pipe/Event/ShareDataAdapterProxyBrokerDelegatorMediatorPublish-SubscribeorObserverProtectedProblem:Howtodesignobjects,subsystems,andsystemssothatthevariationsorinstabilityintheseelementsdoesnothaveanundesirableimpactonotherelements?Solution:Identifypointsofpredictedvariationorinstability;assignresponsibilitiestocreateastableinterfacearoundthem.InformationDatadriven(configurationServicelookup(runtimeReflectiveorMeta-LevelDesigns(ComponentUniformAccess(adherencetoLawofDemeter(restrictcommunicationRuleofWhentherearealternativedesignchoicestakeacloserlookatthecohesionandcouplingimplicationsofthealternativesandpossiblyathefutureevolutionpressuresonthealternatives.Chooseternativewithgoodcohesion,couplingandstability.審美標準是什易(availability可以正常工作reliability故障和故障修復列舉已知的設計方法與技術（至少5中），他們促進了那些審美標準的低層設計（代碼設計底層設計將基本的語言單位（類型與語句），+算DefensiveTest-DrivenErrorhandling,exceptionConfiguringTable-drivenState-mathinebased中層設計（模塊與類結構設計為什么要設計名稱匹配,導入導出（問題Inside接口（獨立，區(qū)別對待架構復習筆記(3)--體系結構的風主程序/(MainProgram/Subroutine面象風格(Object-Oriented分層風格(Layered隱式調用風格(ImplicitInvocation很難進試和驗管道過濾器風格(Pipe-Filter庫風格(RepositoryMVC約束ViewModelViewModelControlModelViewControlModelViewViewControlModel應用：MVC客戶端/服務器風格(Client/Server變種：BS，3-Tier，P2P～～～Distributed設計模普通ProgrammingtoInterface有哪些？集合類型PTI有那些ProxyPrototypeOCP有那些（提示：不只是繼承Beopenforextension:module’sbehaviorcanbeBecloseformodification:sourcecodeforthemodulemustnotbeAggregationDynamicBinding:Startupbinding:ConfigrationLoadBinding:ComponentAdherencetodefinedModifiabilityLocalizeSemanticLimitpossiblecommonPreventionofrippleHideMaintainexistingUseanDeferbindingRuntimeComponentAdherencetodefinedbasicsecrete:externalbehaviorVSinternalhidestheimple