3 Replies Latest reply on Nov 16, 2006 11:52 AM by Alberto Martinez

    Seam + Hibernate + MVC

    Alberto Martinez Newbie

      Hi.

      First of all, sorry for my english :D

      I am newby using seam and I am trying to develope a web application with a MVC layer model (I have no choose, I didn't design the application).

      I am some confused about what annotations a need for each layer and I can't find any example that implements this model. Anyone can help me?:

      Entity:

      @Entity
      @Name("libro")
      @Scope(CONVERSATION)
      @Table(name = "libros")
      public class Libro implements Serializable {
      
       private static final long serialVersionUID = -1252025299985845136L;
      
       private String isbn;
      
       private String titulo;
      
       private String autor;
      
       @Id
       @Column(name = "isbn")
       public String getIsbn() {
       return isbn;
       }
      
       public void setIsbn(String isbn) {
       this.isbn = isbn;
       }
      
       @NotNull
       @Column(name = "titulo")
       public String getTitulo() {
       return titulo;
       }
      
       public void setTitulo(String titulo) {
       this.titulo = titulo;
       }
      
       @NotNull
       @Column(name = "autor")
       public String getAutor() {
       return autor;
       }
      
       public void setAutor(String autor) {
       this.autor = autor;
       }
      }
      


      Service Interface:
      @Local
      public interface LibroManager {
       ...
       public void add();
       ...
      }
      


      Service Implementation:
      @Stateful
      @Name("libroManager")
      @Scope(CONVERSATION)
      public class LibroManagerAction implements LibroManager, Serializable {
      
       private static final long serialVersionUID = 4607492839166551543L;
      
       @In(required = false)
       @Out(required = false)
       private Libro libro;
      
       private LibroDAOhbn libroDAO = new LibroDAOhbn();
      
       ...
       public void add() {
       libroDAO.Create(libro);
       }
       ...
      }
      


      Dao Interface:
      @Local
      public interface LibroDAO {
       public void Create(Libro libro);
      
      }
      


      Dao Implementation:
      @Stateless
      @Name("libroDAO")
      
      public class LibroDAOhbn implements LibroDAO {
      
       @PersistenceContext
       private EntityManager em;
      
       public void Create(Libro libro) {
       System.out.println("Registrando " + libro.getTitulo());
      
       try {
       em.persist(libro);
       } catch (Exception e) {
       System.out.println(e.getMessage());
       }
       }
      
      }
      


      Ok, when the Create(libro) method is called, I only get an exception: NULL. I think that this is caused because I lost the EntityManager or Entity context, but I don't know how to mend it.

      I try to inject the libroDAOhbn in the service class with:
      @In (create=true)
      private LibroDAOhbn libroDAO = new LibroDAOhbn();
      


      but I get an error everytime I call any service's method. I think that it must to have an easy solution, but I can't find it :). Some suggestions?

      If I don't use a DAO layer and I do all the implementation in the service/controller , I have no problems. This runs perfectly:
      @Stateful
      @Name("libroManager")
      @Scope(CONVERSATION)
      public class LibroManagerAction implements LibroManager, Serializable {
      
       private static final long serialVersionUID = 4607492839166551543L;
      
       @In(required = false)
       @Out(required = false)
       private Libro libro;
      
       private LibroDAOhbn libroDAO = new LibroDAOhbn();
      
       ...
       public void add() {
      
       try {
       em.persist(libro);
      
       FacesMessages.instance().add( "Insertado correctamente: " + libro.getTitulo());
      
       } catch (Exception e) {
       System.out.println("Exception: " + e.getMessage());
       }
       ....
       }
      

      but I need the DAO's :(

      Thank's for all.

      PS: Sorry for my englis again.