It works perfectly. Thank you
Cid On 6 août, 20:19, "Jason (Google)" <[email protected]> wrote: > This may be related to the fetch group of the classes field. Try replacing > the appropriate lines in School.java with this: > @Persistent(mappedBy = "school", defaultFetchGroup = "true") > private List<Classe> classes = new ArrayList<Classe>(); > > Let me know if this works for you. > > - Jason > > 2009/8/4 Cédric Chevarier <[email protected]> > > > > > Hi, > > > I have a problem with a one-to-many relationship. Here is my code > > > Class School : > > > @PersistenceCapable(identityType = IdentityType.APPLICATION) > > public class School implements IsSerializable{ > > �...@primarykey > > �...@persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) > > private Key key; > > �...@persistent > > private String name; > > �...@persistent > > private String structure; > > �...@persistent(mappedBy = "school") > > private List<Classe> classes = new ArrayList<Classe>(); > > //..... > > } > > > Class Classe : > > > @PersistenceCapable(identityType = IdentityType.APPLICATION) > > public class Classe implements IsSerializable{ > > �...@persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) > > �...@primarykey > > private Key key; > > �...@persistent > > private String name; > > �...@persistent > > private School school; > > �...@persistent > > private String schoolName; > > //.... > > } > > > Code to add a Classe (it's work) > > > public String addClasse(Classe classe) { > > PersistenceManager pm = PMF.get().getPersistenceManager(); > > Key key2 = > > KeyFactory.createKey(School.class.getSimpleName(), > > classe.getSchoolName()); > > School school2 = (School) pm.getObjectById(School.class, > > key2); > > Key key = new > > KeyFactory.Builder(School.class.getSimpleName(), > > school2 > > > .getName()).addChild(Classe.class.getSimpleName(), > > classe.getName()).getKey(); > > classe.setKey(key); > > school2.addClasses(classe); > > pm.makePersistent(school2); > > pm.close(); > > return "ok"; > > } > > > Code to get all Classes (It's the problem) > > > public List<Classe> getClasseSchool(String schoolName){ > > PersistenceManager pm = PMF.get().getPersistenceManager(); > > Key key = KeyFactory.createKey(School.class.getSimpleName(), > > schoolName); > > School school = (School) pm.getObjectById(School.class, > > key); > > List<Classe> classeList = new ArrayList<Classe>(); > > classeList = school.getClasses(); > > return classeList; > > > } > > > When I try to retreive the ClassList I have got this error : > > [ERROR] Uncaught exception escaped > > java.lang.NullPointerException: null > > > Can you help me ?? > > > Cédric > > > OS : Mac OS X 10.5 > > App Engine SDK : 1.2.2 > > GWT SDK : 1.7.0 > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
