One Seam component calling another

[breako]

Hi,
I know it is very easy for a JSP or XHTML to refer to a Seam component through an EL. However I am wondering how one Seam component refers to another? I do not wish to have one Seam component instantiating another, I wish one to look the other up, similar to EJB?
Any ideas?
Thanks in advance

[sebastiendeg]

Hello,


As far I know, there are 2 ways :

1: use @In annotation. (recommended)

2: use Component.getInstance() (from non-seam component)

Have a look for options in booth technique.

Correct if I'm wrong.
Cheers,

[breako]

"sdegardin" wrote:

1: use @In annotation. (recommended)

Thanks for your suggestion. I used the @In annotation but the problem is that the second Seam component does not get it's Seam managed EntityManager set up correctly.

Basically, I have two Seam components both involved in the same transacation. Both Seam Components have Seam managed EntityManagers and because there are involved in the same transaction, the persistence context should be propagated and shared.

First Seam Component:

@Name("manager")
@Scope(CONVERSATION)
public class ManagerPojo {

 @In
 private EntityManager em;

 @In (required=false, value="instancegenerator", create=true)
 private InstanceGeneratorPOJO instanceGeneratorPOJO;

 @Begin(join=true, flushMode=FlushModeType.MANUAL)
 public void persist() {
 //...
 instanceGeneratorPOJO.getNextInstance("Person");
 //...
 }

 //...
}

Second Seam Component:

@Name("instancegenerator")
@Scope(CONVERSATION)
public class InstanceGeneratorPOJO {
 @In
 private EntityManager entityManager;

 public Long getNextInstance(String type) {
 //...
 }

}

When persist() is invoked I get:

15:50:41,937 FATAL [application] org.jboss.seam.RequiredException: @In attribute requires non-null value: instancegenerator.entityManager
javax.faces.el.EvaluationException: org.jboss.seam.RequiredException: @In attribute requires non-null value: instancegenerator.entityManager

Note: If I remove the create=true in the first Seam component, i.e.

 @In (required=false, value="instancegenerator")
 private InstanceGeneratorPOJO instanceGeneratorPOJO;

the instanceGenerator reference is null and I get a Null pointer exception in the persist() method

anybody got any ideas?

[gsegura]

Hi,
it could be just the different variable name:

private EntityManager em;

and

private EntityManager entityManager;

regards

[sebastiendeg]

"gsegura" wrote:
Hi,
it could be just the different variable name:

private EntityManager em;

and

private EntityManager entityManager;

regards

and if you don't want to use component name has field name, specify the component name in the "value" parameter of the In annotation

@In(value="em") private EntityManager entityManager;

Cheers,

[breako]

Thanks for the replies, you spotted my mistake.
Happy New Year!