CDI Ambiguous dependencies

Thor picture Thor · Apr 17, 2012 · Viewed 41.2k times · Source

I have a @SessionScoped @Named bean with a @Producer method for a user object:

@Named @SessionScoped
public class UserBean implements Serializable
{
  //...
  @Named @Produces @LoggedIn @SessionScoped
  public MyUser getCurrentUser() {return user;}
}

This works fine in my setup (JBoss-7.1.1-Final) and it's no problem to access the user fields from JSF pages with #{currentUser.name}. The qualifier is org.jboss.seam.security.annotations.LoggedIn. Now I want to @Inject this user in a field in another @Named Bean:

@Named
public class FavBean implements Serializable
{   
  private @Inject @LoggedIn MyUser currentUser;
}

This gives me the error:

org.jboss.weld.exceptions.DeploymentException:
WELD-001409 Ambiguous dependencies for type [MyUser] with qualifiers [@Default] at
  injection point [[field] @Inject @LoggedIn test.FavBean.currentUser].
Possible dependencies [[Managed Bean [class test.ejb.MyUser] with qualifiers
  [@Any @Default],
Producer Method [MyUser] with qualifiers [@Any @Default] declared as [[method]
  @Named @Produces @LoggedIn @SessionScoped public test.UserBean.getCurrentUser()]]]

I don't understand the first dependency Managed Bean [class test.ejb.MyUser] This class is a simple @Entity and deployed in an ebb.jar in a EAR. As a workaround I'm currently injecting the UserBean get the user from there.

Answer

Matt Handy picture Matt Handy · Apr 17, 2012

This is because CDI searches for beans by type and your entity and the producer method return the same type. That's why it is ambiguous.

You need to define a new qualifier and annotate it with your producer method.

@Qualifier
@Retention(RUNTIME)
@Target({METHOD, FIELD, PARAMETER, TYPE})
public @interface CurrentUser {
}

Add this annotation to your producer method:

@Named @Produces @CurrentUser @LoggedIn @SessionScoped
public MyUser getCurrentUser() {return user;}