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From Michelle Caisse <Michelle.Cai...@Sun.COM>
Subject Re: Support java.lang.Object as FCO
Date Wed, 17 Aug 2005 22:14:57 GMT
Hi Craig,

I think the spec could be more explicit.  Embedded and serialized are 
syntactically orthogonal but not semantically orthogonal,  therefore 
they should be discussed together somewhere. The spec should state that 
embedded="true" and serialized="true" are mutually exclusive.  Also a 
discussion of the meaning of embedded="false" serialized="false" for PC 
instances would be useful.  Maybe this belongs in Chapter 15.

-- Michelle

Craig Russell wrote:

> Hi Andy,
>
> On Aug 17, 2005, at 10:39 AM, Andy Jefferson wrote:
>
>> Hi Michelle,
>>
>>
>>> It seems that jpox maps Object as serialized by default.  Where  
>>> there is
>>> no serialized or embedded attribute on the field, we map to a FK  
>>> column,
>>> e.g. OBJECT102 BIGINT REFERENCES SIMPLE_CLASS, giving a jpox error:
>>>
>>
>> Well we interpret all types as serialized="false", but in section  
>> 18.14 of the
>> spec "java.lang" types (which Object is) are to be embedded="true" by
>> default. So we interpret this as serialising the Object into the  
>> table of the
>> class, into a BLOB column.
>
>
> I tried to be more explicit about this in the Proposed Final Draft,  
> to say that embedded="true" doesn't mean serialized but embedded  
> column by column. Just like embedded PC instances.
>
> Could you please take a look at the PFD and see if this is not clear  
> enough?
>
> Thanks,
>
> Craig
>
>>
>>
>>> SimpleInterface, which we map identically to Object, works fine.
>>>
>>
>> Because we treat an Interface as embedded="false" by default (since  
>> it's not
>> specified in the list of embedded types in 18.14, so its effectively a
>> PersistenceCapable in that respect).
>>
>>
>> -- 
>> Andy
>>
>
> 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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