第Spring事務處理Transactional,鎖同步和并發線程*LicensedundertheApacheLicense,Version2.0(the"License");

*youmaynotusethisfileexceptincompliancewiththeLicense.

*YoumayobtainacopyoftheLicenseat

*/licenses/LICENSE-2.0

*Unlessrequiredbyapplicablelaworagreedtoinwriting,software

*distributedundertheLicenseisdistributedonan"ASIS"BASIS,

*WITHOUTWARRANTIESORCONDITIONSOFANYKIND,eitherexpressorimplied.

*SeetheLicenseforthespecificlanguagegoverningpermissionsand

*limitationsundertheLicense.

packageorg.springframework.transaction;

importjava.sql.Connection;

*InterfacethatdefinesSpring-complianttransactionproperties.

*BasedonthepropagationbehaviordefinitionsanalogoustoEJBCMTattributes.

*pNotethatisolationlevelandtimeoutsettingswillnotgetappliedunless

*anactualnewtransactiongetsstarted.Asonly{@link#PROPAGATION_REQUIRED},

*{@link#PROPAGATION_REQUIRES_NEW}and{@link#PROPAGATION_NESTED}cancause

*that,itusuallydoesn'tmakesensetospecifythosesettingsinothercases.

*Furthermore,beawarethatnotalltransactionmanagerswillsupportthose

*advancedfeaturesandthusmightthrowcorrespondingexceptionswhengiven

*non-defaultvalues.

*pThe{@link#isReadOnly()read-onlyflag}appliestoanytransactioncontext,

*whetherbackedbyanactualresourcetransactionoroperatingnon-transactionally

*attheresourcelevel.Inthelattercase,theflagwillonlyapplytomanaged

*resourceswithintheapplication,suchasaHibernate{@codeSession}.

*@authorJuergenHoeller

*@since08.05.2003

*@seePlatformTransactionManager#getTransaction(TransactionDefinition)

*@seeorg.springframework.transaction.support.DefaultTransactionDefinition

*@seeerceptor.TransactionAttribute

publicinterfaceTransactionDefinition{

*Supportacurrenttransaction;createanewoneifnoneexists.

*AnalogoustotheEJBtransactionattributeofthesamename.

*pThisistypicallythedefaultsettingofatransactiondefinition,

*andtypicallydefinesatransactionsynchronizationscope.

intPROPAGATION_REQUIRED=0;

*Supportacurrenttransaction;executenon-transactionallyifnoneexists.

*AnalogoustotheEJBtransactionattributeofthesamename.

*pbNOTE:/bFortransactionmanagerswithtransactionsynchronization,

*{@codePROPAGATION_SUPPORTS}isslightlydifferentfromnotransaction

*atall,asitdefinesatransactionscopethatsynchronizationmightapplyto.

*Asaconsequence,thesameresources(aJDBC{@codeConnection},a

*Hibernate{@codeSession},etc)willbesharedfortheentirespecified

*scope.Notethattheexactbehaviordependsontheactualsynchronization

*configurationofthetransactionmanager!

*pIngeneral,use{@codePROPAGATION_SUPPORTS}withcare!Inparticular,do

*notrelyon{@codePROPAGATION_REQUIRED}or{@codePROPAGATION_REQUIRES_NEW}

*iwithin/ia{@codePROPAGATION_SUPPORTS}scope(whichmayleadto

*synchronizationconflictsatruntime).Ifsuchnestingisunavoidable,makesure

*toconfigureyourtransactionmanagerappropriately(typicallyswitchingto

*"synchronizationonactualtransaction").

*@seeorg.springframework.transaction.support.AbstractPlatformTransactionManager#setTransactionSynchronization

*@seeorg.springframework.transaction.support.AbstractPlatformTransactionManager#SYNCHRONIZATION_ON_ACTUAL_TRANSACTION

intPROPAGATION_SUPPORTS=1;

*Supportacurrenttransaction;throwanexceptionifnocurrenttransaction

*exists.AnalogoustotheEJBtransactionattributeofthesamename.

*pNotethattransactionsynchronizationwithina{@codePROPAGATION_MANDATORY}

*scopewillalwaysbedrivenbythesurroundingtransaction.

intPROPAGATION_MANDATORY=2;

*Createanewtransaction,suspendingthecurrenttransactionifoneexists.

*AnalogoustotheEJBtransactionattributeofthesamename.

*pbNOTE:/bActualtransactionsuspensionwillnotworkout-of-the-box

*onalltransactionmanagers.Thisinparticularappliesto

*{@linkorg.springframework.transaction.jta.JtaTransactionManager},

*whichrequiresthe{@codejavax.transaction.TransactionManager}

*tobemadeavailableittoit(whichisserver-specificinstandardJ2EE).

*pA{@codePROPAGATION_REQUIRES_NEW}scopealwaysdefinesitsown

*transactionsynchronizations.Existingsynchronizationswillbesuspended

*andresumedappropriately.

*@seeorg.springframework.transaction.jta.JtaTransactionManager#setTransactionManager

intPROPAGATION_REQUIRES_NEW=3;

*Donotsupportacurrenttransaction;ratheralwaysexecutenon-transactionally.

*AnalogoustotheEJBtransactionattributeofthesamename.

*pbNOTE:/bActualtransactionsuspensionwillnotworkout-of-the-box

*onalltransactionmanagers.Thisinparticularappliesto

*{@linkorg.springframework.transaction.jta.JtaTransactionManager},

*whichrequiresthe{@codejavax.transaction.TransactionManager}

*tobemadeavailableittoit(whichisserver-specificinstandardJ2EE).

*pNotethattransactionsynchronizationisinot/iavailablewithina

*{@codePROPAGATION_NOT_SUPPORTED}scope.Existingsynchronizations

*willbesuspendedandresumedappropriately.

*@seeorg.springframework.transaction.jta.JtaTransactionManager#setTransactionManager

intPROPAGATION_NOT_SUPPORTED=4;

*Donotsupportacurrenttransaction;throwanexceptionifacurrenttransaction

*exists.AnalogoustotheEJBtransactionattributeofthesamename.

*pNotethattransactionsynchronizationisinot/iavailablewithina

*{@codePROPAGATION_NEVER}sc