webwork-talkWebWork 2

WebWork2.0,StruttingtheOpenSymphonyWay,WhatisOpenSymphony?,AnopensourceprojectencompassingqualityenterpriseJavacomponentsManywellknownqualitycomponentsWebWork/XWorkSiteMeshOSCacheOSUserOSWorkflowQuartz,WhatisWebWork2.0?,ThesecondgenerationofWebWorkAwebMVCframeworkAwrapperontopofagenericCommandPatternimplementation(XWork)Asmallbutpowerfultaglibrary,HowdoesWebWorkuseXWork?,XWorkisagenericcommandpatternimplementationWebWorktranslatesbetweenthewebworldandXWork,WhatdoesXWorkprovide?,CommandpatternimplementationActionsarecommandobjectsinXWorkAddsadvancedfeaturesInterceptorsIncludessettingparameters,workflow,etcResultsIncludesoneforchainingtoanotherActionSimpleIoC(or“DependencyInjection)containerPowerfulexpressionlanguageOGNLFlexibletypeconversionMetadatadrivenvalidationframework,WhatdoesWebWorkadd?,AdapterforHTTPrequest/responseIntegrationofSession/ApplicationscopesServletDispatchertranslatesHTTPrequestsintoActionexecutionRequestparameterspassedtoActionResultsforservletredirect,ActionSupport,ActionsareonlyrequiredtoimplementtheActioninterfaceActionSupportisausefulbaseclassImplementsActionProvideserrormessagesupportFieldandActionlevelmessagesMessagesautomaticallyusedbyUItagsProvidesmessageinternationalizationMessagebundleforeachActionLooksupclasshierarchyUItagsuseinternationalizationsupporttofindtextAllfeaturesbasedonInterfaces,soyoucanimplementyourownfromscratch!,A“HelloWorld”example,SimplerequirementsTaketheusersnameandgenerateahellomessagepersonalizedforthemIftheuserentersabirthday,calculatehowlonguntiltheirbirthdayShowsImplementinganActionConfiguringWebWorkUsingthetaglibTypeconversionErrormessages,HelloWorldAction.java,publicclassHelloWorldActionextendsActionSupportprivateUseruser=newUser();publicUsergetUser()returnuser;publicintgetDaysTillNextBirthday()publicStringexecute()throwsExceptionStringname=getUser().getName();if(name=null)|(name.trim().equals()addFieldError(,Youmustenteraname.);if(hasErrors()returnINPUT;returnSUCCESS;,User.java,publicclassUserprivateStringname;privateDatebirthday;publicStringgetName()returnname;publicvoidsetName(Stringname)=name;publicDategetBirthday()returnbirthday;publicvoidsetBirthday(Datebirthday)this.birthday=birthday;,form.jsp,HelloWorldExample,success.jsp,HelloHello!daystillyournextbirthday.,Xwork.xmlforHelloWorld,/field/form.jsp/field/success.jsp/field/form.jsp,UnittestingActions,XWork/WebWorkshinesintestabilityActionshavenowebdependencies,soyoudonthavetosetupmocks,etc.2waysoftestingActionsJustcreateanewinstance,setsomeproperties,andexecuteUsetheframeworkdirectlyinyourteststoexecuteitwiththeInterceptors,etc.,HelloWorldActionTest,publicvoidtestFieldErrorAddedWhenNoUserName()throwsExceptionHelloWorldActionaction=newHelloWorldAction();assertEquals(Action.INPUT,action.execute();assertTrue(action.hasFieldErrors();MapfieldErrors=action.getFieldErrors();assertTrue(fieldErrors.containsKey();ListuserNameErrors=(List)fieldErrors.get();assertEquals(1,userNameErrors.size();assertEquals(Youmustenteraname.,userNameErrors.get(0);,Notesontheexample,ComposepagemodelfrommanyobjectsusingexpressionlanguageUItagsautomaticallyshowfielderrormessagesnexttotheformfieldReturncodefromActiondetermineswhichpagetodisplayMuchofthe“magic”isintheinterceptors,Interceptors:DomainAOP,InterceptorsallowcustomcodeintothecallstackMuchofthecorefunctionalityofXWorkandWebWorkisimplementedasInterceptorsAddcustomInterceptors,TimerInterceptor,TimerInterceptoristhesimplestInterceptorJusttimestheexecutionoftheActionpublicStringintercept(ActionInvocationinvocation)throwsExceptionif(log.isInfoEnabled()longstartTime=System.currentTimeMillis();Stringresult=invocation.invoke();longexecutionTime=System.currentTimeMillis()-startTime;Stringnamespace=invocation.getProxy().getNamespace();,LoggingInterceptor,LoggingInterceptorextendstheAroundInterceptorAroundInterceptorprovidescallbacksforbefore()andafter()theActionisexecutedpublicclassLoggingInterceptorextendsAroundInterceptorprotectedvoidafter(ActionInvocationinvocation,Stringresult)throwsExceptionlogMessage(invocation,FINISH_MESSAGE);protectedvoidbefore(ActionInvocationinvocation)throwsExceptionlogMessage(invocation,START_MESSAGE);,OtherInterceptors,SettingParametersParameterInterceptorStaticParameterInterceptorChainingInterceptorConversionErrorInterceptorDefiningWorkflowDefaultWorkflowInterceptorPrepareInterceptorServletConfigInterceptorPreventingduplicateposts2typesoftokeninterceptors,InterceptorStacks,InterceptorscanbegroupedintonamedInterceptorStacks2definedinwebwork-default.xmldefaultStackvalidationWorkflowStackStackscanbebuiltofotherstacksandinterceptors,Model-Drivenvs.Field-Driven,2typesofActionspossible:Model-drivenActionhasmethodsreturningyourmodelclasses(myAction.getUser()FieldsintheviewarefieldsofyourmodelViewsreferdirectlytoyourmodel(property=)ExcellentbecauseitallowsmodelreuseField-drivenActionhasfieldsofitsown,whicharefieldsintheviewexecute()collatesfieldsandinteractswiththemodelViewsrefertoactionfields(property=daysTillNextBirthday)UsefulwhereformisnotparalleltomodelAswecanseeinourAction,thetwocanbemixed,ModelDrivenInterface,XWork/WebWorkalsosupportsmodel-drivenActionsmoredirectlyTheModelDrivenInterfacehasonemethod:publicObjectgetModel()Propertiesofthemodelwillbedirectlyavailable,i.e.“name”insteadof“”AppliestoUItags,formfieldnames,etc.,MakingHelloWorldModelDriven,MaketheclassimplementModelDrivenChangegetUser()togetModel()publicclassHelloWorldActionextendsActionSupportimplementsModelDrivenpublicObjectgetModel()returnuser;,ModelDriven:ChangestotheJSP,Change“”,etc.tojust“name”Inform.jspInsuccess.jspHello!daystillyournextbirthday.,ApplyingtheModelDrivenInterceptor,Inxwork.xml/model/form.jsp/model/success.jsp/model/form.jsp,LookingattheModelInterceptor,TheModelInterceptorpushestheModelontotheValueStack,WhatistheValueStack?,TheValueStackbuildsastackofobjectsObjectsareusedtofindpropertyvaluesTheValueStackallowstheexpressionlanguagetofindpropertyvaluesacrossmultipleobjects,HowistheValueStackused?,TheActioninstanceisalwayspushedontotheValueStackTheModelispushedonbytheModelInterceptorTheUItagsuseittopushvaluesonduringtheirscopeandevaluateexpressionsThetagpushesthecurrentitemontothestackThetagpushesabeaninstanceonThetagevaluatesanexpressionagainsttheValueStackAlltagattributevaluesareevaluatedagainstthestackwhenbeingsetontothetaginstances,TheOGNLexpressionlanguage,ForexpressionsWWusesOGNL(ObjectGraphNavigationLanguage)anexpressionandbindinglanguageforgettingandsettingpropertiesofJavaobjectsNormallythesameexpressionisusedforbothgettingandsettingthevalueofapropertyEasytolearn,yetpowerfulIncrementallycompiledexpressions-fast!Embeddedeverywhereviews,ValueStack,*.xmlIndependentlyrunOpenSourceproject-,OGNLsamples,TheXWorkValidationFramework,SeparatesvalidationfromActionclassesAllowsfordifferentvalidationsindifferentcontextsforthesameobjectProvideshooksforlocalizedvalidationmessages2typesofvalidators,Objectlevelandfieldlevel,HelloWorldAction-validation.xml,Youmustenteraname.ValidationfileinthesamepackageastheclassDefinesonefieldvalidatorandtheerrormessagetoaddifitfails,BundledValidators,Changestoxwork.xml,/field/success.jsp/field/form.jspvalidationWorkflowStackisfromwebwork-default.xml,ChangestotheAction,Theexecute()methodcanjustreturnSUCCESSpublicStringexecute()throwsExceptionreturnSUCCESS;Thevalidationofthe“”propertyishandledbythevalidationinterceptorTheworkflowinterceptorreturnsINPUTifthereareanyerrorsaddedtotheAction,WhatisInversionofControl?,IoCremovestheonusofmanagingcomponentsfromyourbusinesslogicintoacontainer.Containermanageslifecyclesanddependenciesbetweencomponents.EJBisIoC,butwithastaticlistofservicesSecurity,persistenceandtransactionsJakartaAvalon,SpringsBeanFactory,andPicoContainerareallIoCcontainers,AdvantagesofIoC,PromotessimplicityanddecouplingComponentsdescribethemselvesDependenciesarediscoveredautomaticallyAdherestoLawofDemeterClassescoupledtoonlywhattheyuseEncouragessmallerresponsibilityclassesLeadstobetterinterface/implseparationUnittestsbecomefarsimplertheybecomemini-containers,IoCinXWork/WebWork,XWorkprovidesasimpleIoCcontainerWebWorkprovidesahierarchyofcontainersmappedtowebscopesApplicationSessionRequestXWorkActionComponentsspecifyonlywhichservicestheyrequireviainterfaces(egShoppingCartAware)Configurationfiledefinescomponentimplementationsandscopes.,AShoppingCartService,AShoppingCartservice-providesauserscart(sessionscoped)ShoppingCartAware.java:publicinterfaceShoppingCartAwarepublicvoidsetShoppingCart(ShoppingCartcart);ShoppingCart.java:publicinterfaceShoppingCartpublicvoidaddPet(Petpet);publicvoidremovePet(Petpet);publicbooleanisEmpty();publicintsize();publicListgetPets();,APetStoreService,APetStoreservice-providesmanagementofourpetinventory(applicationscoped)PetStoreAware.java:publicinterfacePetStoreAwarepublicvoidsetPetStore(PetStorestore);PetStore.java:publicinterfacePetStorevoidsavePet(Petpet);voidremovePet(Petpet);ListgetPets();PetgetPet(longid);,AserviceclientAction,publicclassAddToCartimplementsAction,PetStoreAware,ShoppingCartAware.publicvoidsetPetStore(PetStoreps)this.petStore=ps;publicvoidsetShoppingCart(ShoppingCartc)this.cart=c;publicStringexecute()throwsExceptionif(cart=null|petId=0)returnERROR;Petpet=petStore.getPet(petId);cart.addPet(pet);returnSUCCESS;,ConfiguringServices,Theseservicesareconfiguredincomponents.xmllikeso:applicationorg.petsoar.pets.DefaultPetStoreorg.petsoar.pets.PetStoreAwaresessionorg.petsoar.cart.SimpleShoppingCartorg.petsoar.cart.ShoppingCartAware,AchievingreusewithWebWork,WebWorkprovidesmanyopportunitiesformodularizingandreusingcomponentsMakeInterceptorstodoworkbeforeandaftertheActionisexecutedCreateserviceswhichareappliedviaIoCCreateActionbaseclassesCreatereusableUIcomponentsCreatereusableapplicationmodules,ReusableUIcomponents,TheWebWorkUItagsareimplementedusingVelocitytemplatesYoucanprovideyourowntemplatesforthetagsThetagletsyouuseanytemplateExamplesAdatepickertemplateErrormessagetemplate,UItagrendering,UItagsuseVelocitytoactuallyre