[jboss-jira] [JBoss JIRA] Updated: (JBRULES-2793) Storing Entity Manager in a Global Environment Map is NOT Threadsafe

Storing Entity Manager in a Global Environment Map is NOT Threadsafe -------------------------------------------------------------------- Key: JBRULES-2793 URL: https://jira.jboss.org/browse/JBRULES-2793 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Affects Versions: 5.1.1.FINAL, FUTURE Environment: N/A Reporter: Anatoly Polinsky Assignee: Mark Proctor Labels: drools_persistence Attachments: env.get.em.png Original Estimate: 2 days Remaining Estimate: 2 days Currently persistence context / entity manager, once created, being placed to a global [ passed to almost every component ] 'Environment' map under "XYZ_SCOPED_ENTITY_MANAGER" key. In order to access this persistence context at runtime, all of the drools persistence components follow the same pattern, which is just accessing the map: e.g. EntityManager em = ( EntityManager ) env.get( EnvironmentName.CMD_SCOPED_ENTITY_MANAGER ); While it works for a single threaded application [ a "playground" type of application I assume ], it does not work in a multi-threaded environment. Simple example would be: one thread belongs to a transaction that is committed, which cleans up resources on commit, including closing this "shared" entity manager another thread grabs this entity manager from the "env" map, and throws various exceptions, since a state of this entity manager ranges from being closed to reopen ( e.g. by the third thread ), etc.. In general, Persistence Context live span should be as short as possible, hence bound to a life span of a Transaction, which is actually normally thread bound. So in order to access this Persistence Context from various Drools components, things like Transactions and Threads need to be respected. This is how an entity manager can be accessed with Spring's help: EntityManagerFactory emf = ( EntityManagerFactory ) env.get( EnvironmentName.ENTITY_MANAGER_FACTORY ); EntityManagerHolder emHolder = ( EntityManagerHolder ) TransactionSynchronizationManager.getResource( emf ); EntityManager em = emHolder.getEntityManager(); Granted Drools is aimed to provide integration with more than just Spring, but the above example actually respects a current Transaction as well as a current Thread. /Anatoly P.S. Attached (PNG) is the list of files which use a "global" env map to access "CMD_SCOPED_ENTITY_MANAGER", hence causing various concurrency problems. There are more files that use an application scoped key, that can be found as easily.