[2.0] Hibernate DAO problem

[Bence]

I would like to use Hibernate from outside the controller classes. I get the following exception:

[RuntimeException: No EntityManager bound to this thread. Try to annotate your action method with @play.db.jpa.Transactional]

@play.db.jpa.Transactional
private static AuthUser getUserByNameAndPass(String userName, String password){
    return (AuthUser) JPA.em().createNamedQuery(AuthUser.getByCredentials).setParameter("userName", userName).setParameter("password", password).getSingleResult();
}

[Bence]

Now I modified:

return (AuthUser) JPA.em("pu").createNamedQuery(AuthUser.getByCredentials).setParameter("userName", userName).setParameter("password", password).getSingleResult();

...and now I'm getting a new error:

Execution exception [[RuntimeException: No JPA EntityManagerFactory configured for name [auth]]]

my conf/META-INF/persistence.xml is:

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
    version="2.0">

    <persistence-unit name="pu" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <non-jta-data-source>MyDS</non-jta-data-source>

        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
            <property name="hibernate.hbm2ddl.auto" value="update" />
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.format_sql" value="true" />
        </properties>
    </persistence-unit>

</persistence>

[Bence]

Is there a way to get more detailed exceptions? It does not help too much:

play.core.ActionInvoker$$anonfun$receive$1$$anon$1: Execution exception [[RuntimeException: No JPA EntityManagerFactory
configured for name [auth]]]
        at play.core.ActionInvoker$$anonfun$receive$1.apply(Invoker.scala:82) [play_2.9.1.jar:2.0]
        at play.core.ActionInvoker$$anonfun$receive$1.apply(Invoker.scala:63) [play_2.9.1.jar:2.0]
        at akka.actor.Actor$class.apply(Actor.scala:290) [akka-actor.jar:2.0]
        at play.core.ActionInvoker.apply(Invoker.scala:61) [play_2.9.1.jar:2.0]
        at akka.actor.ActorCell.invoke(ActorCell.scala:617) [akka-actor.jar:2.0]
        at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:179) [akka-actor.jar:2.0]
Caused by: java.lang.RuntimeException: No JPA EntityManagerFactory configured for name [auth]
        at play.db.jpa.JPA.em(JPA.java:33) ~[play_2.9.1.jar:2.0]
        at com.stepman.ag.auth.AuthenticationService.getByCredentials(AuthenticationService.java:80) ~[classes/:na]
        at com.stepman.ag.auth.AuthenticationService.handleAuthentication(AuthenticationService.java:29) ~[classes/:na]
        at com.stepman.ag.controllers.Login.authenticate(Login.java:20) ~[classes/:na]
        at Routes$$anonfun$routes$1$$anonfun$apply$3$$anonfun$apply$4.apply(routes_routing.scala:52) ~[classes/:na]
        at Routes$$anonfun$routes$1$$anonfun$apply$3$$anonfun$apply$4.apply(routes_routing.scala:52) ~[classes/:na]

[Bence]

Solved.

I needed to add the following line to application.conf:
jpa.default=pu

[brainwatch]

Hi Bence

As per the documentation @Transactional can be applied only for the Controller actions. I wonder how did you manage to get this stuff working. After stumbling on this post I tried the same and it does not work.

My use case is :
I have to catch the transactional exception and throw a readable error json message to the user which I'm not able to achieve 'cos of @transactional annotation handles the rollback automatically which makes the controller not go through the catch block at all.

Any suggestion ?

-bw

[Bence]

Did you use @play.db.jpa.Transactional and JPA.em() ?
It is working for me without anything else (extending/implmenting anything, or having any other kind of annotation)

[brainwatch]

Yes. I tried the same but not working.

- bm

[brainwatch]

Were you able to catch the transactional exception ( Runtime ) and handle it ( In you logic you should be able to ). Let me know is there any hack you have made to make it work.

- bm

[Bence Takács]

Good question ;-)
No, I have only a POC, not a production app. You should ask more experienced players.

[Bence]

So, let me see:
There is no answer, because this is a very conscious concept not to create DAOs in Play.

Since Anorm and Ebean so conscise and practical that there is no need to that concept.
 
...and this is why there is no answer to this kind of questions:
https://groups.google.com/forum/#!searchin/play-framework/DAO/play-framework/I1hwzBXVvxU/4rP5JPmzAhsJ
https://groups.google.com/forum/#!searchin/play-framework/DAO/play-framework/ZNNafEyUIn4/b2h2RKctgRcJ

[Bence]

Well, maybe I know the reason. There are three conditions needed:
- use @play.db.jpa.Transactional
- on a static method
- use JPA.em() to achieve the entityManager

I used a static method - which is not conventional for DAOs, but conventional in Play ;-)