List, I'm answering myself, but may be of help to somebody.
Finally i have found the problem: The Qualifier (or Discriminator) has to be of type character and not Integer. ...my first intent was to use integer in order to follow our local policies for enumerations. Hans ----- [email protected] escribió: > Dave, > > I've implemented the inheritance as the tutorial say, it worked fine, > but the factory method still need to get the initial artist class to > know the type, then ask cayenne again to give the right class to > instantiate. > > I think there may be another way to get the object without doing this > double call to objectForPK. > > public static Artist getArtist(String id) { > > if (id == null || id.equals("")) > return null; > > DataContext context = DataContext.getThreadDataContext(); > > Artist c = (Artist) DataObjectUtils.objectForPK(context, > Artist.class, Integer.parseInt(id)); > > if (c.getTipoEnum() == EnumTipoArtist.EXPERT) > return (Artist) DataObjectUtils.objectForPK(context, > ExpertArtist.class, > Integer.parseInt(id)); > else > return c; > } > > Thanks > Hans > > ----- "Dave Lamy" <[email protected]> escribió: > > > Hey Hans-- > > > > While I'm certain that the inheritance structure isn't data based > to > > you, I > > imagine that Cayenne is going to HAVE to have a data value to know > > which > > subclass to instantiate. It's effectively going to get back a row > > from the > > Artist table and be asked to transform that row into an Artist > object. > > How > > can it determine which kind? Through some sort of data analysis. > > Either a > > particular attribute value (ARTIST_TYPE) or via a linked table > > structure > > (don't think Cayenne supports that yet?). That data attribute > should > > not be > > of particular importance to your application, however. It's just > an > > ORM > > crutch. > > > > Dave > > > > On Mon, Mar 2, 2009 at 8:41 AM, <[email protected]> wrote: > > > > > Michael, > > > > > > Thank you, i already saw it, but my intent was to make it > entirely > > outside > > > cayenne mappings, the problem i need to solve is just behavioral, > > not data > > > based... by the way, it's not clear how to try the example using > > the > > > modeler: creating an empty class with no attributes or something. > > > > > > Hans > > > > > > ----- "Michael Gentry" <[email protected]> escribió: > > > > > > > Is this what you are after? > > > > > > > > http://cayenne.apache.org/doc/handling-inheritance.html > > > > > > > > > > > > On Sun, Mar 1, 2009 at 7:46 PM, <[email protected]> wrote: > > > > > Hi, > > > > > > > > > > I'm trying to implement a factory method pattern based on a > > cayenne > > > > data object. > > > > > > > > > > Say for example i have a class (cayenne based) called Artist, > i > > want > > > > to make a subclass of Artist, say ExpertArtist that implements > > some > > > > specific behavior. > > > > > > > > > > Actually i have a big static Factory class that give me the > all > > > > objects, i have a method like this: > > > > > > > > > > public static Artist getArtist(String id) { > > > > > > > > > > if (id == null || id.equals("")) > > > > > return null; > > > > > > > > > > DataContext context = > > > > DataContext.getThreadDataContext(); > > > > > > > > > > Artist object = (Artist) > > > > DataObjectUtils.objectForPK( > > > > > context, Artist.class, > > > > Integer.parseInt(id)); > > > > > return object; > > > > > } > > > > > > > > > > Obviously i can declare ExpertArtist as an subclass of > Artist. > > > > > > > > > > package xxx.xxx; > > > > > > > > > > public class EspertArtist extends Artist { > > > > > public String getName() { > > > > > return super.getName() + " i'am expert !!"; > > > > > } > > > > > } > > > > > > > > > > I've tried to instantiate an ExpertArtist, just modifying the > > > > Factory method, with no results. I don't know how to bouild the > > parent > > > > class calling super or something... > > > > > > > > > > Obviously these are not the real classes, the actual classes > > are > > > > really big and this solution: just modifying the factory method > is > > the > > > > best for me. > > > > > > > > > > > > > > > Thanks > > > > > Hans > > > > > > > > > > > > > > > > > > > > > -- > > > Hans Poo, WeLinux S.A. > > > Oficina: 697.25.42, Celular: 09-319.93.05 > > > Bombero Ossa # 1010, Santiago > > > > > > > > -- > Hans Poo, WeLinux S.A. > Oficina: 697.25.42, Celular: 09-319.93.05 > Bombero Ossa # 1010, Santiago -- Hans Poo, WeLinux S.A. Oficina: 697.25.42, Celular: 09-319.93.05 Bombero Ossa # 1010, Santiago
