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

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

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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