[hibernate-issues] [Hibernate-JIRA] Commented: (ANN-526) Property xyz has an unbound type - is that so?

[Emmanuel Bernard (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/ANN-526?page=comments#action_25907 ] 

Emmanuel Bernard commented on ANN-526:
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1 - The system tries to be smart and approximates all generic types as well as it can. List<T extends Runnable> becomes List<Runnable>, T becomes Object and so on. This might cause problems at runtime, of course.

> I'm OK for everything but Object, if you declare an upper bound, you tend to know what you are doing. However, for Object people would be too surprised, esp the one not understqnding generics ( like me :-) )

2 - The system does as above, but logs a warning every time an approximated type is registered.

-1, we had that but the user experience was bad for Hibernate Validator

3 - The system approximates only in certain situations. Maybe different approximation strategies can be plugged in.

An approximation strategy might be interesting, we sort of have that through the boolean rendering true/false depending on whether approximation was used or not

4 - The system doesn't try to be too smart, and throws an error whenever a type is not fully resolved. 

-1 there are usecases that require approximation

> Property xyz has an unbound type - is that so?
> ----------------------------------------------
>
>          Key: ANN-526
>          URL: http://opensource.atlassian.com/projects/hibernate/browse/ANN-526
>      Project: Hibernate Annotations
>         Type: Bug

>     Versions: 3.2.1
>     Reporter: Sebastian Kirsch
>     Assignee: Paolo "Nusco" Perrotta
>     Priority: Minor
>  Attachments: Hibernate ANN-526.zip
>
>
> I get this "Property reference has an unbound type and no explictit target entity" exception and I think this is not exactly true. I'm not sure if this is a bug or a feature requests though.
> Have a look at the attached files and read on.
> I guess the model ist pretty easy to understand. The AbstractGeneric allows my to have concrete entities referring to specifc other subclasses - as seen in ConcreteOther and ConcreteSelf. The test case "workingClasses" shows us that Hibernate may work with this model - note that the class AbstractGeneric itslef was NOT added to the configuration.
> Now for the problem: The class OtherEntity is a completly different entity, but it refers to instances of AbstractGeneric - to any subclass of it actually, as AbstractGeneric is obviously abstract.
> If you run the test case "otherClass" the first part states that Hibernate doesn't know AbstractGeneric - which is fine, so I add that class to the configuration and try to build a session factory again. Now we receive the beforementioned exception.
> That's the situation. So is AbstractGeneric really an unbound type? I'd say it is not - T has an upper bound which should be good enough to work with - we know the table and the PK...

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