The persist framework takes care that every thread has its own entity manager. So you don't need to do this. Calling unitOfWork.end() will close the entity manager for you. So also no need to do this manually.
The unitOfWork is a singleton. So you can inject it directly and don't need to use the provider. You must use the provider for the entityManager as you do. Also important: @Transactional works using interception at runtime. Threrefore it can only be used on non private, non final and non static methods. Because for private, final, or static methods the code can be inlined by the compiler. Then it is no longer possible to intercept the method call at runtime. Am 13. Mai 2015 14:35:39 MESZ, schrieb "JB Lézoray" <[email protected]>: >Hi Laszio, > >Thank you for your answer. > >I think you pinpointed the problem, and I'm a step forward in resolving >it. > >Here is the MyRunnable implementation, it already relies on two >providers for EntityManager and UnitOfWork. >But now my question is : how to make sure that >the Provider<EntityManager> in the MyRunnable worker returns >another EntityManager than the one in the MyServletWorker ? > > > > >// A time consuming job. >class MyRunnable implements Runnable { > > @Inject Provider<EntityManager> entityManagerProvider; > > @Inject Provider<UnitOfWork> unitOfWorkProvider; > > @Override > public void run() > { > UnitOfWork unitOfWork = null; > EntityManager em = null; > try { > unitOfWork = unitOfWorkProvider.get(); > unitOfWork.begin(); > em = entityManagerProvider.get(); > this.doTimeConsumingStuff(em); > } finally { > if (unitOfWork != null) unitOfWork.end(); > if (em != null && em.isOpen()) em.close(); // should it be >explicitly closed ? > } > } > > @Transactional > private void doTimeConsumingStuff(EntityManager em) {/* ... */} >} > > >// Executed within the http worker thread. >// It Creates and submits the jobs. >class MyServletWorker { > > @Inject Provider<EntityManager> entityManagerProvider; > > @Inject ExecutorService executorService; > > public void createAndSubmitJobs(MyData data) { > EntityManager em = entityManagerProvider.get(); > Set<MyRunnable> jobs = createJobs(em, data); > for (MyRunnable job : jobs) > executorService.submit(job); > // .... > } > > @Transactional > public Set<MyRunnable> createJobs(EntityManager em, MyData data) {/* >... */} >} > > >Le 13 mai 2015 à 13:16:59, Laszlo Ferenczi ([email protected]) a >écrit: > >Hi, > >I think the issue will be in the MyRunnable class. >You create the MyRunnable instance in the http worker thread, if you >simply inject an EntityManager there it'll be the one bound to the >current thread (the http worker). After submitting it to a different >thread you essentially leak the transaction which can have many side >effects (like when the same http worker is selected again, the >PersistFilter will try to start a new transaction but it's already open >for that thread - held by the long running background job). > >The correct way to handle this is to inject a Provider<EntityManager> >in MyRunnable and annotate the database using methods with >@Transactional. > >-- >L > > >-- >L > >On Wed, May 13, 2015 at 11:58 AM, jbl <[email protected]> >wrote: >Hello, > > >I'm relatively new to guice, and I've got a problem that I quite don't >understand. > >I have a webapp based on guice, eclipse link, mysql that runs on a >tomcat 7. The app uses a >com.google.inject.persist.jpa.JpaPersistModule and >a com.google.inject.persist.PersistFilter > >For some requests the webapp creates a set of java.lang.Runnable, >passes them to a java.util.concurrent.ExecutorService, and returns. >The runnables are numerous time-consuming jobs that must be executed in >background to avoid blocking the request. Also, each job has to access >the EntityManager. However, the current implementation is quite naive: > > @Inject private Provider<MyRunnable> myRunnableProvider; > @Inject private ExecutorService executorService; > > MyRunnable runnable = myRunnableProvider.get(); > executorService.submit(runnable); > >This code runs fine on my development computer, but I get this >exception when I run it in a production environment : > >java.lang.IllegalStateException: Work already begun on this thread. >Looks like you have called UnitOfWork.begin() twice without a balancing >call to end() in between. > at >com.google.common.base.Preconditions.checkState(Preconditions.java:150) >~[guava-15.0.jar:na] > at >com.google.inject.persist.jpa.JpaPersistService.begin(JpaPersistService.java:73) >~[guice-persist-4.0.jar:na] > at com.jbl.MyRunnable.run(MyRunnable.java:107) > >I think that this has something to do with the Scope, but I don't quite >understand how to correct this. > >Thank you for any insight on this ! > >-- >You received this message because you are subscribed to the Google >Groups "google-guice" group. >To unsubscribe from this group and stop receiving emails from it, send >an email to [email protected]. >To post to this group, send email to [email protected]. >Visit this group at http://groups.google.com/group/google-guice. >To view this discussion on the web visit >https://groups.google.com/d/msgid/google-guice/141ea4f0-3f34-45c9-a8cf-c28779859a2d%40googlegroups.com. >For more options, visit https://groups.google.com/d/optout. > >-- >You received this message because you are subscribed to a topic in the >Google Groups "google-guice" group. >To unsubscribe from this topic, visit >https://groups.google.com/d/topic/google-guice/JKPs9sayXi4/unsubscribe. >To unsubscribe from this group and all its topics, send an email to >[email protected]. >To post to this group, send email to [email protected]. >Visit this group at http://groups.google.com/group/google-guice. >To view this discussion on the web visit >https://groups.google.com/d/msgid/google-guice/CAD-udUCC6FM2w9wGHNdUcMyZD6FQykHfGpUW%3DNveLu7UTawPkw%40mail.gmail.com. >For more options, visit https://groups.google.com/d/optout. > >-- > >Jean-Baptiste LÉZORAY >Ingénieur Logiciel >Portable: 06 64 86 32 92 >[email protected] >Bâtiment Nucléole - 85 rue de Saint-Brieuc - 35 000 RENNES >Retrouvez-nous sur www.dolmen.bzh > >-- >You received this message because you are subscribed to the Google >Groups "google-guice" group. >To unsubscribe from this group and stop receiving emails from it, send >an email to [email protected]. >To post to this group, send email to [email protected]. >Visit this group at http://groups.google.com/group/google-guice. >To view this discussion on the web visit >https://groups.google.com/d/msgid/google-guice/etPan.5553451b.66334873.5aa0%40MBA-JB.local. >For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "google-guice" group. 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