@Service / @Management bean injection

[rhomber]

Hey All,

I am just getting my hands dirty with Seam for the first time after months of deliberation. I have setup an EJB3 service that I would like to inject into a seam component/bean. I have tried using both @In and @EJB using the class name and the interface, as well as @EJB(name="blah") (blah being the objectName for the service). None of these approaches seem to work, all @In attempts result in a Seam error stating the item is null, all @EJB attempts result in the property being left null.

Any ideas? I am a little lost..

Cheers,

David

[swd847]

Have you tried @In(create=true) or annoting the EJB with @AutoCreate ?

[rhomber]

Yeah, I just tried it then. I didn't try it before because the service is initialized when it's deployed. It didn't help, I am still getting the same error..

10:39:34,308 ERROR [ExceptionFilter] uncaught exception
javax.servlet.ServletException: In attribute requires non-null value: authenticator.gajService


Granted EJB3 and Seam are not the same thing, but because Seam operates within the EJB container, surely there is a way of operating with an EJB3 service? I really don't want to have to do a JNDI lookup :( That would suck.

Hope someone can help,

David

[rhomber]

Perhaps I should rephrase my question. Assuming I implemented a service following the tutorial: http://docs.jboss.com/ejb3/app-server/tutorial/service/service.html - How would I inject that service into my Seam component? Would I need to inject it by a remote or local interface, or by the management interface?

I currently have the following:

Management Interface:

@Management
public interface GAJServiceMBean extends ServiceMBean {
....
}

Local Interface:

@Local
public interface GAJServiceLocal {
....
}

Remote Interface:

@Remote
public interface GAJServiceRemote {
....
}

Implementation:

@Service(objectName = "utiba:service=GAJ")
public class GAJService extends ServiceMBeanSupport implements GAJServiceMBean, GAJServiceLocal, GAJServiceRemote, Serializable {
 // Serial Version
 protected static final long serialVersionUID = 10234234234L;

 ......
}

I have tried some of the following injection combinations:

@In GAJServiceMBean gajService;

@EJB GAJServiceMBean gajService;
@EJB GAJServiceLocal gajService;
@EJB GAJServiceRemote gajService;

The first results in the not-null condition, the rest result in the object remaining null.

Cheers,

David

[norman.richards]

@Service creates an MBean, not an EJB. We don't provide a way to lookup MBeans (though perhpaps we should?) so you should implement the JNDI lookups yourself - using @Factory or maybe @Unwrap.

[rhomber]

Hey,

I found a feature request that suggests there is a way of doing it: http://jira.jboss.org/jira/browse/JBSEAM-1498

I am not stuck with the fact that I cannot inject a stateless bean either. Perhaps my understanding of how Seam works is wrong.

I have a stateless bean:

@Name("utibaServiceGajMediator")
@Stateless
@Scope(ScopeType.APPLICATION)
@AutoCreate
public class GAJServiceMediatorBean implements GAJServiceMediator {

 public int nextTransID() throws Exception {
 return 1234;
 }

}

Implementing interface:

@Local
public interface GAJServiceMediator {

 public int nextTransID() throws Exception;

}

And then used by this class:

@Name("utibaTester")
@AutoCreate
public class UtibaTest {

 @In GAJServiceMediator gajServiceMediator;
 @In MyBean myBean;

 public void takeMagicFlight() {
 try {
 myBean.setText("TransID = " + gajServiceMediator.nextTransID());
 } catch (Exception e) {
 myBean.setText("Failed");
 }
 }

}

Then elsewhere I have a commandLink:

<h:commandButton type="submit" value="Fly Away" action="#{utibaTester.takeMagicFlight}"/>

And get the following error message:

Caused by: javax.faces.el.EvaluationException: /ajax.xhtml @22,102 action="#{utibaTester.takeMagicFlight}": org.jboss.seam.RequiredException: In attribute requires non-null value: utibaTester.gajServiceMediator
 at com.sun.facelets.el.LegacyMethodBinding.invoke(LegacyMethodBinding.java:73)
 at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:63)
 ... 43 more
Caused by: org.jboss.seam.RequiredException: In attribute requires non-null value: utibaTester.gajServiceMediator

Well that is the useful portion anyway. As far as I can tell I have followed the documentation, perhaps my understanding of how all this should work together is wrong? Should I be able to have one stateless bean injected as a resource to another bean?

Any help would be appreciated.

Cheers,

David

[michael.c.small]

Have you tried @Resource for your injection. Since @Service classes are stored in JNDI, I don't see why the @Resource wouldn't work.

[norman.richards]

We've had several requests for this, so I've scheduled that for 2.0.1.

[matt.drees]

"rhomber" wrote:

@Name("utibaServiceGajMediator")
...
public class GAJServiceMediatorBean implements GAJServiceMediator {

}

And then used by this class:

...
 @In GAJServiceMediator gajServiceMediator;

...

org.jboss.seam.RequiredException: In attribute requires non-null value: utibaTester.gajServiceMediator

Your names don't match; gajServiceMediator != utibaServiceGajMediator

[rhomber]

Hey All,

Thanks so much for helping. I didn't know that the instance variable had to be the same name as the @Name, I thought it was injected based on the class. Thanks for clarifying this, I feel a bit silly :). It all works fine now, and I was able to inject the service via another means that seems a little less tacky than the JNDI lookup (@Resource). However, I would love a Seam built-in to handle it as is suggested above. I simply used the method described in: http://jira.jboss.org/jira/browse/JBSEAM-1498 as a work around and it worked fine.

Cheers and thank you,

David