A totally optional part of the Seam Application Framework is the class Controller and its subclasses EntityControllerHibernateEntityController and BusinessProcessController. These classes provide nothing more than some convenience methods for access to commonly used built-in components and methods of built-in components. They help save a few keystrokes (characters can add up!) and provide a great launchpad for new users to explore the rich functionality built in to Seam.

For example, here is what RegisterAction from the Seam registration example would look like:

@Stateless
@Name("register")
public class RegisterAction extends EntityController implements Register
{

   @In private User user;
   
   public String register()
   {
      List existing = createQuery("select u.username from User u where u.username=:username")
         .setParameter("username", user.getUsername())
         .getResultList();
      
      if ( existing.size()==0 )
      {
         persist(user);
         info("Registered new user #{user.username}");
         return "/registered.jspx";
      }
      else
      {
         addFacesMessage("User #{user.username} already exists");
         return null;
      }
   }

}

As you can see, its not an earthshattering improvement...