DynamicObjectRequest动态对象请求

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1、DynamicObjectRequestsOutlineMotivatingExamplesDynamicInvocationReflectionDesigningGenericApplications1DynamicObjectRequestsOutlineMotivatingExamplesDynamicInvocationTheCORBADynamicInvocationInterfaceReflectionTheCORBAInterfaceRepositoryDesigningGenericApplicationsUsingCORBA2Dyn

2、amicObjectRequestsMotivation3DynamicObjectRequestsWhatisadynamicrequest?SometimesclientsneedtobebuiltbeforetheirserverinterfacesaredefinedTheyneedtodeferrequestdefinitionuntiltheyareexecutedThesearedynamicrequestsExamples:ObjectbrowserGenericbridgesScriptinglanguageinterpreter4

3、DynamicObjectRequestsMotivatingExample:ObjectBrowserMotivatingExample:GenericBridgeClientORBCoreORBCoreObj.Imp.DSIDIIGenericandrequest-levelbridge6DynamicObjectRequestsCommonalitiesDiscoveryoftypeinformationatrun-timeUseoftypeinformationtobuildclientobjectsthatcancopewithanytyp

4、eofserverobjectsDefinitionofobjectrequestsatrun-timeRequirestwoprimitivesfrommiddleware:DynamicinvocationinterfacesReflectionmechanisms7DynamicObjectRequestsDynamicInvocation8DynamicObjectRequestsDynamicRequests:PrinciplesAnyobjectrequesthastoidentifyserverobjectoperationnameac

5、tualparametersdatastructureforoperationresultInDynamicRequests:serverobjectidentifiedbyobjectreferenceoperationnameidentifiedbystringactualparametersaslistofname/valuepairsoperationresultdeterminedbyanaddress9DynamicObjectRequestsDynamicInvocationClientStubsORBInterfaceImplemen

6、tationSkeletonsClientObjectImplementationORBCoreObjectAdapterDynamicRequestsinCORBADynamicRequestsinCORBADynamicinvocationinterface(DII)supportsdynamiccreationofrequests.Requestsareobjectsthemselves.Requestobjectshaveattributesforoperationname,parametersandresults.Requestobject

7、shaveoperationstochangeoperationparameters,issuetherequestandobtaintherequestresults.11DynamicObjectRequestsDynamicRequestinCORBA:Clientrr:Request:ServerOp()r=create_request(…,”Op”,…)add_arg()invoke()delete()CreatingDynamicCORBARequestsinterfaceObject{ORBstatuscreate_request(in

8、Contextctx,//operationcontextinIdentifieroperation,//o