I don't do JPA, but If it's like JDO and you have lazy loading then don't you need to access the subjects field before you close your entity manager to get the subjects loaded? Just a thought.
On Mon, Jan 17, 2011 at 3:51 PM, kidowell <[email protected]> wrote: > I cannot retreive the List<subjects> from book. The save and update of a > book when a subject changes its fine, the problem is when retreiving books, > It doeesnt retreive their subjects. I need help. Here;s the code. > > @Entity > @Table(name = "book") > public class Book implements Serializable, IsSerializable { > > @Id > @GeneratedValue(strategy = GenerationType.IDENTITY) > private Key id; > private String bookName; > private String comment; > @OneToMany(mappedBy="book",cascade = CascadeType.ALL) > private List<Subject> subjects; > > //setters and getters > > -------------------------------------------------------------------------------------- > > @Entity > @Table(name = "subject") > public class Subject implements Serializable, IsSerializable { > > @Id > @GeneratedValue(strategy = GenerationType.IDENTITY) > private Key id; > private String name; > private int visible; > @Basic > private Text content; > @Basic > @ManyToOne > private Book book; > // setters and getters > > > ---------------------------------------------------------------------------------------------------- > > public List<Book> getBooks() throws GeneralException, > BookNotFoundException, NullParameterException { > entityManager = EMF.get().createEntityManager(); > List<Book> list; > try { > String sql = "SELECT b FROM Book b"; > list = > entityManager.createQuery(sql).getResultList(); //this list is > retreived with the books but without their subjects > } catch (Exception e) { > throw new GeneralException("Exception in method getBookes: " + > e.getMessage()); > } finally { > if (entityManager.isOpen()) { > entityManager.close(); > } > } > if (list == null || list.isEmpty()) { > > throw new BookNotFoundException("Book not found in method > getBookes"); > } > return list; > } > > > Please, I need some help. > > Cheers. > > -- > Kido. > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" group. > To post to this group, send email to > [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-appengine-java%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine-java?hl=en. > -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
