I'll let leszek talk more about the code, but I assumed that the
commented out line was just testing both scenarios. In the scenario
without comment on the line, it would be my scenario: the same "owned
type" but not the same "owned instance".
My original question is not about one particular entity having two
parents (in an owned relationship), but having two entity groups share
the same "owned" Java type.
Does that make sense?
On Sep 21, 2:00 pm, Marton Papp <mapr...@gmail.com> wrote:
> Hi,
>
> The code in that form also works for me, but just because the
> exception is caught and never reported. If you rethrow any exceptions
> from the catch blocks than you should get something like the
> following:
>
> Detected attempt to establish Parent2(3) as the parent of Parent1(1)/
> Child1(2) but the entity identified by Parent1(1)/Child1(2) is already
> a child of Parent1(1). A parent cannot be established or changed once
> an object has been persisted.
> org.datanucleus.exceptions.NucleusUserException: Detected attempt to
> establish Parent2(3) as the parent of Parent1(1)/Child1(2) but the
> entity identified by Parent1(1)/Child1(2) is already a child of Parent1
> (1). A parent cannot be established or changed once an object has
> been persisted.
> at
> org.datanucleus.store.appengine.DatastoreRelationFieldManager.checkForParentSwitch
> (DatastoreRelationFieldManager.java:214)
> at org.datanucleus.store.appengine.DatastoreRelationFieldManager
> $1.setObjectViaMapping(DatastoreRelationFieldManager.java:129)
> at org.datanucleus.store.appengine.DatastoreRelationFieldManager
> $1.apply(DatastoreRelationFieldManager.java:108)
> at
> org.datanucleus.store.appengine.DatastoreRelationFieldManager.storeRelations
> (DatastoreRelationFieldManager.java:80)
> at
> org.datanucleus.store.appengine.DatastoreFieldManager.storeRelations
> (DatastoreFieldManager.java:795)
> at
> org.datanucleus.store.appengine.DatastorePersistenceHandler.insertPostProcess
> (DatastorePersistenceHandler.java:288)
> at
> org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObjects
> (DatastorePersistenceHandler.java:241)
> at
> org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObject
> (DatastorePersistenceHandler.java:225)
> at org.datanucleus.state.JDOStateManagerImpl.internalMakePersistent
> (JDOStateManagerImpl.java:3185)
> at org.datanucleus.state.JDOStateManagerImpl.makePersistent
> (JDOStateManagerImpl.java:3161)
> at org.datanucleus.ObjectManagerImpl.persistObjectInternal
> (ObjectManagerImpl.java:1298)
> at org.datanucleus.ObjectManagerImpl.persistObject
> (ObjectManagerImpl.java:1175)
> at org.datanucleus.jdo.JDOPersistenceManager.jdoMakePersistent
> (JDOPersistenceManager.java:669)
> at org.datanucleus.jdo.JDOPersistenceManager.makePersistent
> (JDOPersistenceManager.java:694)
> at hu.mapro.gae.test.forum.TestForum.testMultiParent(TestForum.java:
> 44)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at sun.reflect.NativeMethodAccessorImpl.invoke
> (NativeMethodAccessorImpl.java:39)
> at sun.reflect.DelegatingMethodAccessorImpl.invoke
> (DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:597)
> at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:59)
> at org.junit.internal.runners.MethodRoadie.runTestMethod
> (MethodRoadie.java:98)
> at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:
> 79)
> at
> org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters
> (MethodRoadie.java:87)
> at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:
> 77)
> at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:42)
> at org.junit.internal.runners.JUnit4ClassRunner.invokeTestMethod
> (JUnit4ClassRunner.java:88)
> at org.junit.internal.runners.JUnit4ClassRunner.runMethods
> (JUnit4ClassRunner.java:51)
> at org.junit.internal.runners.JUnit4ClassRunner$1.run
> (JUnit4ClassRunner.java:44)
> at org.junit.internal.runners.ClassRoadie.runUnprotected
> (ClassRoadie.java:27)
> at org.junit.internal.runners.ClassRoadie.runProtected
> (ClassRoadie.java:37)
> at org.junit.internal.runners.JUnit4ClassRunner.run
> (JUnit4ClassRunner.java:42)
> at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run
> (JUnit4TestReference.java:46)
> at org.eclipse.jdt.internal.junit.runner.TestExecution.run
> (TestExecution.java:38)
> at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests
> (RemoteTestRunner.java:467)
> at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests
> (RemoteTestRunner.java:683)
> at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run
> (RemoteTestRunner.java:390)
> at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main
> (RemoteTestRunner.java:197)
>
> The error message is self-explanatory. According to my knowledge it is
> impossible for a single entity to have multiple parents, just as it is
> impossible to change the parent of an entity (or any other part of its
> primary key).
>
> But you were talking about a "class" being in owned realationship with
> two different classes, not an "entity". If I remove the comment from
> the code above that creates a new child entity before assigning it to
> the second parent instance then it is working as expected. Of course
> they will be two different employee instances with different parents
> (of different types).
>
> Marton
>
> On Sep 21, 4:49 pm, leszek <leszek.ptokar...@gmail.com> wrote:
>
> > That's very interesting because it works for me:
>
> > @PersistenceCapable(identityType = IdentityType.APPLICATION)
> > public class Employee {
>
> > @PrimaryKey
> > @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
> > private Key id;
>
> > private String firstName;
>
> > private String lastName;
>
> > }
>
> > @PersistenceCapable(identityType = IdentityType.APPLICATION)
> > public class A (B) {
>
> > public Long getId() {
> > return id;
> > }
>
> > public void setId(Long id) {
> > this.id = id;
> > }
>
> > public Employee getE() {
> > return e;
> > }
>
> > public void setE(Employee e) {
> > this.e = e;
> > }
>
> > @PrimaryKey
> > @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
> > private Long id;
>
> > }
>
> > ========================
> > (regardless if transaction is used or not - simply makePersistent
> > without transaction)
>
> > PersistenceManager em = EMF.get().getPersistenceManager();
> > Employee e = null;
> > try {
> > em.currentTransaction().begin();
> > A a = new A();
> > e = new Employee();
> > a.setE(e);
> > em.makePersistent(a);
> > em.currentTransaction().commit();
> > } catch (Exception ee) {
> > em.currentTransaction().rollback();
> > }
>
> > try {
> > em.currentTransaction().begin();
> > B b = new B();
> > // e = new Employee();
> > b.setE(e);
> > em.makePersistent(b);
> > em.currentTransaction().commit();
> > } catch (Exception ee) {
> > em.currentTransaction().rollback();
> > }
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