13.4. Controller objects

@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; 
    } 
  } 
}