[hibernate-issues] [Hibernate-JIRA] Commented: (ANN-539) Generics and @Embedded doesn't work

[Christophe Vanfleteren (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/ANN-539?page=comments#action_25870 ] 

Christophe Vanfleteren commented on ANN-539:
--------------------------------------------

Emmanuel,

I'm not quite sure I quite follow your argument:

I'd use Range<Integer> on the setBounds, as in

Example e = new Example();
Range<Integer> bounds = new Range<Integer>(0,10);
e.setBounds(bounds);

Hibernate can create an instance of Range using newInstance, and it can fill up the min/max fields of it, it just needs a way to know what type those fields should have when it hydrates.

If you could do something like this:

	@AttributeOverrides({
		 @AttributeOverride(name="min", column = @Column(name="min_size"), type=@Type(type="int") ),
		 @AttributeOverride(name="max", column = @Column(name="max_size"), type=@Type(type="int")  )
	})
	private Range<Integer> sizeBounds;
	
	
	@AttributeOverrides({
		 @AttributeOverride(name="min", column = @Column(name="min_date"),type=@Type(type="date") ),
		 @AttributeOverride(name="max", column = @Column(name="max_date"),type=@Type(type="date") )
	})
	private Range<Date> dateBounds;

then you'd be able to use the single Range<T> class in the same entity (you could problably also guess the correct type using the Parameterized types of the fields).  Kind of like you could do when using mapping files (mapping the same class as a component twice, only using different types for the fields). 

As it stands now, you need to make a specialized implementation every time you plan to use a Range of a different type.

> Generics and @Embedded doesn't work
> -----------------------------------
>
>          Key: ANN-539
>          URL: http://opensource.atlassian.com/projects/hibernate/browse/ANN-539
>      Project: Hibernate Annotations
>         Type: Bug

>     Versions: 3.2.1
>  Environment: Hibernate 3.2.1, Oracle 10XE
>     Reporter: Christophe Vanfleteren
>  Attachments: generic.zip
>
>
> It doesn't seem to be possible to use a plain generic field as a component,
> for example:
> @Embedded
> private Range<Integer> bounds
> doesn't work (you get an "org.hibernate.AnnotationException: Property generic.GenericRange.min has an unbound type and no explicit target entity. Resolve this Generic usage issue or set an explicit target attribute (eg @OneToMany(target=) or use an explicit @Type") error.
> It does work when you extend the generic class in which you define the type (IntegerRange extends Range<Integer>)
> for example:
> @Embedded
> private IntegerRange bounds
> works
> I've attached some classes that demeonstrate this problem. This issue was raised before in http://opensource.atlassian.com/projects/hibernate/browse/ANN-406?page=comments, but was rejected since no testcase was provided.

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