Re: [eclipselink-users] Exceptions when using generics (was Upgrade from

["Michael O'Brien" <michael.obrien@xxxxxxxxxx>]

Frank,
   Correction, I see Entity MyClass extends MappedSuperclass MyGeneric 
where F is of type MyGenericType
   In this case MyField still must be an Entity, however a 
MyGenericType subclass of MyField could still be a MappedSuperclass as 
in an MS-->E hierarchy like CoordinateMS --> GalacticPosition in our JPA 
test model
UML:
http://wiki.eclipse.org/EclipseLink/Development/JPA_2.0/metamodel_api#Mapped_Superclass_Test_Model
Code:
http://fisheye2.atlassian.com/browse/eclipselink/trunk/jpa/eclipselink.jpa.test/src/org/eclipse/persistence/testing/models/jpa/metamodel/CoordinateMS.java?r=HEAD

   - retesting
   /michael

Michael O'Brien wrote:
> Frank,
>    Hi, I could find no relationship to the MyClass entity in the 
> MyGeneric mappedSuperclass.
>    If MyClass would actually be MyField - then the code should 
> validate ok.
>    Could you supply the code for the MyField class (F in this case 
> should be a concrete entity subclass in your client code).
>    Normally relationships out of MappedSuperclasses must be only to 
> entities.
>
>    For example I get the following expected exception when i target a 
> MappedSuperclass as the target of a OneToOne
>
> Internal Exception: Exception [EclipseLink-7250] (Eclipse Persistence 
> Services - org.eclipse.persistence.exceptions.ValidationException
> Exception Description: [class 
> org.eclipse.persistence.example.dataparallel.model.ScalarProcessingUnit] 
> uses a non-entity [class 
> org.eclipse.persistence.example.dataparallel.model.ProcessingUnit] as 
> target entity in the relationship attribute [field westUnit].
>    at 
> org.eclipse.persistence.exceptions.EntityManagerSetupException.predeployFailed(EntityManagerSetupException.java:210) 
>
>
> @MappedSuperclass
> public abstract class Core {}
>
> @MappedSuperclass
> public abstract class ProcessingUnit<P extends Core> implements 
> Serializable {
>    @OneToOne
>    private ProcessingUnit<P> westUnit;
> }
>
> @Entity(name="DparPU")
> public class ScalarProcessingUnit extends ProcessingUnit implements 
> Serializable {}
>
>    If I instead reference the entity subclass for the @OneToOne 
> (virtually the same as a  @ManyToOne) -  I no longer get a validation 
> exception.
>
>    @OneToOne
>    private ScalarProcessingUnit westUnit;
>
>    thank you
>    /michael
>
>
> Frank von Daak wrote:
> > Hello again,
> >
> > after searching the whole day for a solution, I try to get a little 
> > help on the list.
> >
> > After upgrading from Eclipselink 1.1.0 to 2.0.2, I always get 
> > Exceptions, when starting up the application:
> >
> > Caused by: Exception [EclipseLink-7250] (Eclipse Persistence Services 
> > - 2.0.2.v20100323-r6872): 
> > org.eclipse.persistence.exceptions.ValidationException
> > Exception Description: [class de.myapp.domain.MyClass] uses a 
> > non-entity [class java.lang.String] as target entity in the 
> > relationship attribute [field myfield].
> >
> > I am using Generics - mabye, this causes the problem!?
> >
> > The classes look like this:
> > --------------------------------------------
> > @Entity
> > public class MyClass extends MyGeneric<MyGenericType>{
> > ......
> > }  --------------------------------------------
> >
> > @MappedSuperclass
> > @Cache(type=CacheType.NONE, alwaysRefresh=true)
> > public abstract class MyGeneric <F extends MyField > implements 
> > MyInterface {
> >      @ManyToOne
> >    private F myfield;  ....
> > }
> > --------------------------------------------
> >
> > What is wrong with this code?
> > Who can give me a little help?
> >
> > Thank you very much!
> > Frank
> >
> > _______________________________________________
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