Newbie - injection problem (getting null)

[carvo]

Hi all.
Im new in SEAM and Im trying to inject a seam component (anoted with @Name), but all my tries fall into a null pointer...

In a few lines, UploadServiceHome recives a upload request, store the uploaded files and delegate the business to UploadService (talking about modeling, is that a good way?) - processMap(..) method. But the UploadService needs to retrieve database information, stored into FarmStructureDescription (a @Entity). So, im trying to inject FarmStructureDescriptionHome into UploadService, but im getting null....

The relevant codes:

@Name("uploadServiceHome")
@Scope(ScopeType.PAGE)
public class UploadServiceHome extends EntityHome<UploadService> {
     
     private static final long serialVersionUID = 6478064206304267363L;
     
     @In(create = true)
     CompanyHome companyHome;
     
     private Map<String, String> filesPaths = new HashMap<String, String>();
     
     public void upload(UploadEvent event) {
          
          ......

          filesPaths.put(fileExtension, pathname);
          try {
                  getInstance().processMap(filesPaths);
          } 
          catch (IOException e) {
               e.printStackTrace();
          }
     }
}

public class UploadService implements Serializable{
     ....
     
        @In(create = true)
        FarmStructureDescriptionHome farmStructureDescriptionHome;
     
     
        public String processMap(Map<String, String> filesPaths) throws IOException {
         
              List<?> descriptions = farmStructureDescriptionHome.getDescriptions(company);
              descriptions.size();
          return "OK";
        }
}

some problem to inject into a Serializable object?

Someone please...
Modeling tips and comments are welcome too!

Thxx,

Carvo

[cash1981]

Your UploadService needs to be a seam component as well.
So you need to put @Name("uploadService") on it.

[carvo]

Hi Shervin,

many thx for your reply.

Sorry my inattention, i've put it but i'm still getting null. Something with PAGE SCOPE TYPE ?? I have no ideas...

Thx again.

CARVO.

[cash1981]

Please show stacktrace

[cosmo]

Is your FarmStructureDescriptionHome also a seam component?

[lrpieri]

Hi all,
Now I'm working with Carvo and we continue with the same  injection problem. I'm working in another point of the application and I'm havin a NPE when usin the @Logger.
The error line is log.info("about entityManager: " + entityManager);
I'm thinking we are havin a generic problem with injections. Maybe any configuration?
Someone have any idea?

Thx for all replies.

Pieri

The code is follow:

@Stateless
@Name("farmStructureDAO")
public class FarmStructureDAOImpl implements FarmStructureDAO {

     @Logger private Log log;
     @PersistenceContext private EntityManager entityManager;
     
     public List<FarmStructure> list(){
          log.info("about entityManager: " + entityManager);//NPE
          Query query = entityManager.createQuery("from FarmStructure"); 
          return query.getResultList();
     }
}

[cash1981]

Try using @In instead of @PersistenceContext

[lrpieri]

Hi Shervin,

Many thx for your reply but the log also is null.
About the EntityManager, I've tried with using @In also, but the NPE problem persist. When included the @Logger and I saw it was null too, I imagined the problem is generic for injections.

[cash1981]

Then I suggest you create the project using seam-gen. That will setup the project for you automatically with everything working.

[lrpieri]

The project was created using JBoss Tools. Can it generate any problem?

[lrpieri]

Hi Shervin,

I created another project using JBoss Tools again and I got the same problem. After have the project running, I created one more class with @Logger private Log log and when I try to use log.info it is null.
Are there problems generating projects using jboss tools?

Thx

Pieri