[hibernate-issues] [Hibernate-JIRA] Commented: (ANN-526) Property xyz has an unbound type - is that so?
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http://opensource.atlassian.com/projects/hibernate/browse/ANN-526?page=co...
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Paolo "Nusco" Perrotta commented on ANN-526:
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It's a broader problem than I thought. I'm still not 100% sure that fixing it will
change the behaviour described by Sebastian, but I found other cases that are more clearly
pathological. For example, this is not approximated correctly, even if in theory it
should:
class SomeGenericType<T extends SomeType> {
public T property() {return null;}
}
We don't even have recursive definitions here, but HA still doesn't notice that
the property type can be approximated to a SomeType. The problem is that I focused on
resolving generic types in hierarchies - but there are cases (like the one above) where
you can make a decent approximation of types by just looking at the class itself. It's
not really a bug, as this is on the border of what people should be expecting to do - but
as a feature request, it's very reasonable. What do you think, Emmanuel?
We have many corner cases where type binding doesn't work as well as Java's -
generics in interfaces, inner classes and so on. Java makes extremely difficult to work
reflexively at this level. This one probably deserves fixing, though.
Property xyz has an unbound type - is that so?
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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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