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Home > Archive > Apache JDO Project > December 2005 > [VOTE] Issue 139: Add attribute field-type to element field
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| Author |
[VOTE] Issue 139: Add attribute field-type to element field
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| Craig L Russell 2005-12-20, 5:45 pm |
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| Andy Jefferson 2005-12-21, 2:45 am |
| Hi Craig,
> This proposal would allow more specific field type to be specified at
> deployment time compared to compile time. For example, a field of
> type Object could be specified in the jdo metadata as containing only
> instances of type SimpleClass.
I don't read the proposal as saying that the user should specify the type(s)
as comma-separated if they want a field declared as Object to store class A
or class B or class C. What does the user do when they have a field declared
as Object and want to do this ?
--
Andy
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| erik@jpox.org 2005-12-22, 7:45 am |
| +1 to proposal with Andy's comments
Quoting Andy Jefferson <andy@jpox.org>:
> Hi Craig,
>
>
> I don't read the proposal as saying that the user should specify the type(s)
> as comma-separated if they want a field declared as Object to store class A
> or class B or class C. What does the user do when they have a field declared
> as Object and want to do this ?
>
>
> --
> Andy
>
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| Craig L Russell 2005-12-28, 2:45 am |
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| Michael Bouschen 2005-12-28, 5:46 pm |
| Hi Craig,
> Hi Andy,
>
> I don't have a problem with using the element-type to be a
> comma-separated list as a vendor extension, but in general there is no
> way to map a heterogeneous (Object or interface type) field.
does this apply the metadata attributes field-type, element-type,
key-type and value-type?
>
> So I don't think that we should specify the comma-separated list of
> possible types as a standard technique.
>
> What do others think about this?
I think support for a field with multiple types in its field-type
attribute should not be required. But maybe it makes sense to specify
the syntax as a comma separated list of type names in case a JDO
implementation does support this feature.
Regards Michael
>
> Craig
>
> On Dec 21, 2005, at 12:11 AM, Andy Jefferson wrote:
>
>
>
> Craig Russell
>
> Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
>
> 408 276-5638 mailto:Craig.Russell@sun.com
>
> P.S. A good JDO? O, Gasp!
>
>
--
Michael Bouschen Tech@Spree Engineering GmbH
mailto:mbo.tech@spree.de http://www.tech.spree.de/
Tel.:++49/30/235 520-33 Buelowstr. 66
Fax.:++49/30/2175 2012 D-10783 Berlin
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