EntityProxy injection with Guice - Guice-persist

[koma]

Hi

Starting up a new project using RF and guice-persist on the server-side to start JPA and provide transaction management.

I have a couple of tests going to inject the EntityManager into the services via the ServiceLocator :

public class ApplicationServiceLocator implements ServiceLocator {

Injector injector = null;

public ApplicationServiceLocator() {

injector = Guice.createInjector(new JpaPersistModule("Test"));

injector.getInstance(ApplicationInitializer.class);

}

@Override

public Object getInstance(Class<?> clazz) {

return injector.getInstance(clazz);

}

}

This makes sure that is EntityManager injected into the service layers :

public class WorkerServiceImpl {

@Inject
private EntityManager em;

@Transactional
public List<Contract> getContracts(User user) {
// I can us EntityManager now !! Injected because created this WorkerServiceImpl was created via injector.getInstance
 }

My question : what would be a good approach to inject the EntityManager into an entity class when implementing a service in an entity class ?

What hooks do I have available to do so ?

thx 

Koen

[Magno Machado]

>@Inject
>private EntityManager em;

Don't know how to answer your question, but here you should inject Provider<EntityManager> instead of EntityManager. The reason is that service classes are stored like singletons, and hence you should inject a provider as explained here http://code.google.com/p/google-guice/wiki/JPA#Using_the_inside_transactions

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[koma]

Ok, thx  I figured it out...

First I needed to inject a ServiceLayerDecorator to with Guice like this example project https://github.com/mgenov/injecting-request-factory

And indeed, the EntityManager must be passed as Provider<EntityManager> otherwise it is not ThreadLocal and you run into closed EntityManager exception (because the trheads make concurrent use of the EntityManager).

I got it working.