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From Craig Russell <Craig.Russ...@Sun.COM>
Subject Re: Explicit SingleFieldIdentity in metadata?
Date Sat, 24 Sep 2005 05:42:43 GMT
Hi Matthew,

Yes, users can explicitly identify the single field class of their  
choosing as long as the field type matches the single field identity  
class key type. No problem.

Craig

On Sep 23, 2005, at 3:31 PM, Matthew T. Adams wrote:

> Currently, section 18.6 of the JDO 2.0 PFD states that if for a  
> class identity-type="application", there is no objectid-class  
> attribute, and there is only one primary key field for that class,  
> then the JDO implementation is to use a SingleFieldIdentity  
> subclass as the object id class.  I don't see why users couldn't  
> use a SingleFieldIdentity subclass of their choice.  As such, I  
> would also like for people to be able to use the names of the  
> SingleFieldIdentity subclasses as the value of the objectid-class  
> attribute.  The implementation may or may not support certain  
> combinations of type conversions (object id class is  
> StringIdentity, but the PC class uses an id field of type int);  
> widening combinations should be supported (object id class  
> LongIdentity with the PC class id field of type short, etc).
>
> This is not a huge deal, but I don't see why we shouldn't support  
> metadata declarations of the form
>
> <class name="Foo" identity-type="application" objectid- 
> class="javax.jdo.identity.StringIdentity">...
>
> It's still spec-compliant, as "javax.jdo.identity.StringIdentity"  
> is the name of a valid object id class.
>
> --matthew
>
> Matthew T. Adams
> Corporate Technical Advisor & Senior Consultant
> Mobile:  +1 253 732 1051
> Phone:  +1 206 331 3833
> Fax:  +1 815 331 0952
> matthew.adams@xcalia.com
> P.O. Box 24163
> Federal Way, WA  98093
> www.xcalia.com
>
> <image.jpg>
>
> Xcalia makes implementing SOA easy with agile business  
> intermediation software that combines heterogeneous data with  
> services to easily develop and deploy transactional composite  
> applications.  Enterprises can quickly respond to changing business  
> requirements and dramatically reduce the costs of data access and  
> service integration.
>

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!


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