How do you inject diferent implementations in Seam?

[joaobmonteiro]

Hi guys,

'I´m facing an interesting question in Seam. I have many services that I inject in my managed beans, for example:

//my service interface

public interface IncidenteService {

...

}


//my service implementation

@Name("incidenteService")

public class IncidenteServiceDdsiImpl implements IncidenteService {

...

}


//my service implementation

@Name("incidenteService")

public class IncidenteServiceDajImpl implements IncidenteService {

...

}

//my managedBean

...

@In(create=true)

private IncidenteService incidenteService;

...

In my case, I have to decide according to user profile wich implementation should be injected. If user profile is DDSI, I should use IncidenteServiceDdsiImpl and so on.

Note that I am trying to apply the Strategy Design Pattern and I want Seam to inject the correct implemantion for me.

The question is how can I use Seam to inject the correct implementation?

Of course I can´t have components with same name and same precedence. And in this case, I think that changing precedene will not help at all since I have to choose the right component according to some user information.

So, guys, have you ever resolve this problem?

Thanks!

[bravocharlie.seam.signup.benny.me.uk]

How about

@Name("incidenteServiceDdsi")
public class IncidenteServiceDdsiImpl implements IncidenteService { }

@Name("incidenteServiceXyz")
public class IncidenteServiceXyzImpl implements IncidenteService { }


@Name("incidenteService")
public class IncidenteServiceManager {

   @In
   UserProfile userProfile

   @Unwrap
   public IncidenteService getIncidenteService(){
      if (userProfile.getType() == ...){
         return Component.getInstance("incidenteServiceDdsi");
      } else {
         ...
      }
   }

}

[joaobmonteiro]

Hi Ben,

Thanks for this sweet solution! I was not aware of using @Unwrap.

Looking further in documentation, I wonder if I could use

@Factory('incidenteService') in somewhere like this:

@Name("serviceFactory")

public class ServiceFactory {

     

     @Factory("incidenteService")

     public IncidenteService getIncidenteService(){

             //some business logic to decide

             //which implementation          

     }

}

I will try both approaches.

Thanks again!