Hi,
> Hi,
> Since the nature of the type mapping isn't specified much in the spec, I
> don't see how implementing this in jaws would be not spec compliant,
> although it would be non portable to other app servers. I understand why
> you would want to do this in the bean. I for one would like to see the
> jaws code in whatever state you take it to.
>
What I did is add a <mapping-class> attribute to <cmp-field> of jaws.xml
This goes up to CMPFieldMetaData.
It has a type of MappingInterface and is instanciated at deployment.
It has two method Object get(Object) and Object set(Object)
These methods do the transformation from and to the database.
The get() is used in the getValue of CMPFieldMetaData.
The set() ... I am not there yet...
To make a XML transformation, I would have a XMLMapper that implements
MapperInterface by calling a method on the Object itself. That suppose my
java Object cmp-field implement a XMLLoadable interface with an importXML
and an exportXML.
Really, nothing very special...
Oh yes, another thing, I use nested properties for these kind of mapping
whenever I CAN. I was thinking of this fetaure to Map special objects like
Collection,Tree , ...
Vincent.
> I think an eventual goal must be to make jaws more modular. There are
> several ideas that seem database specific (such as the stable
> rowid stuff),
> and I think it might be good to have optional abilities to do things like
>
> --use a jca resource.cci.connection with interactionspecs instead of jdbc
>
> --use stored procedures for insert, update, delete instead of semi-dynamic
> sql.
>
> david jencks
>
> On 2001.06.09 09:52:32 -0400 Vincent Harcq wrote:
> > Well,
> > I think it is not spec compliant because this fetaure is not
> supported by
> > other appservers. For them I will have to serialize my object to the
> > database. An my original problem was that if the version (serialization
> > speaking) of this object change, I may have problem with old records in
> > the
> > database. Then if I implement a jboss specific feature and abuse of it,
> > I
> > will have to find another trick if I want to deploy my application on
> > another ejb server.
> > That said, I have the trick for these other appserver(explained in last
> > mail) so if you think JBoss could gain by imlementing such a feature, I
> > am
> > still ready to implement it.
> > In fact I have almost finish programming it.
> >
> > BTW, I was also thinking about a XML-Jaws that could use JAXB to store
> > entity beans in XML databases. Just an idea, I have not really think
> > about
> > it.
> >
> > Vincent.
> >
> >
> > > -----Message d'origine-----
> > > De : [EMAIL PROTECTED]
> > > [mailto:[EMAIL PROTECTED]]De la part de
> > > David Jencks
> > > Envoy� : samedi 9 juin 2001 15:30
> > > � : [EMAIL PROTECTED]
> > > Objet : RE: [JBoss-dev] CMP fields XML Serialization
> > >
> > >
> > > Hi,
> > > I thought you had a great idea. I'm very curious about why this was a
> > bad
> > > idea and how it is not spec compliant.
> > >
> > > Thanks
> > > david jencks
> > >
> > > On 2001.06.09 03:52:17 -0400 Vincent Harcq wrote:
> > > > Forget it.
> > > > I find it more spec compliant to have a String cmp field containing
> > my
> > > > XML
> > > > respresentation.
> > > > a getter method that do XML-->Object
> > > > a setter method that do Object-->XML
> > > >
> > > > Anyway, make the storage of cmp field to db field in Jaws is not
> > > > difficult
> > > > but finally I don't think it's a good idea.
> > > >
> > > > Vincent.
> > > > > -----Message d'origine-----
> > > > > De : [EMAIL PROTECTED]
> > > > > [mailto:[EMAIL PROTECTED]]De
> la part de
> > > > > Vincent Harcq
> > > > > Envoy� : vendredi 8 juin 2001 17:47
> > > > > � : [EMAIL PROTECTED]
> > > > > Objet : RE: [JBoss-dev] CMP fields XML Serialization
> > > > >
> > > > >
> > > > > Hi,
> > > > > I will look at this idea, by having a new jdbc-type in
> jaws.xml for
> > > > which
> > > > > parameters can be set that tells Jaws how to insert/retrieve
> > > > > attribute/field.
> > > > > But I still want to keep it simple and keep the constraint one cmp
> > > > field /
> > > > > one database field.
> > > > > Regards.
> > > > > Vincent.
> > > > >
> > > > > > -----Message d'origine-----
> > > > > > De : [EMAIL PROTECTED]
> > > > > > [mailto:[EMAIL PROTECTED]]De la part
> > de
> > > > Bill
> > > > > > Burke
> > > > > > Envoy� : vendredi 8 juin 2001 16:51
> > > > > > � : [EMAIL PROTECTED]
> > > > > > Objet : RE: [JBoss-dev] CMP fields XML Serialization
> > > > > >
> > > > > >
> > > > > > Can you plug-in how a CMP field is stored in the database? If
> > not,
> > > > this
> > > > > > would be the best first step.
> > > > > >
> > > > > > Bill
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: [EMAIL PROTECTED]
> > > > > > >
> [mailto:[EMAIL PROTECTED]]On Behalf
> > Of
> > > > > > > Vincent Harcq
> > > > > > > Sent: Friday, June 08, 2001 3:23 AM
> > > > > > > To: Dev JBoss
> > > > > > > Subject: [JBoss-dev] CMP fields XML Serialization
> > > > > > >
> > > > > > >
> > > > > > > Hi,
> > > > > > > In CMP Entity beans, fields that can not be mapped
> automaticaly
> > > > > > > to primitive
> > > > > > > SQL type are
> > > > > > > serialized and saved as Object in the database. One
> problem is
> > > > > > > then if you
> > > > > > > want to change the Object, you have to take care of
> > Serialization
> > > > > > > versions,...
> > > > > > > everything is not possible here. Another problem is if you
> > > > > want to give
> > > > > > > access
> > > > > > > to your db to a non Java world.
> > > > > > > One solution for that could be to XMLize the object to a
> > > > > VARCHAR/String
> > > > > > > format.
> > > > > > > The power on changes of the Object will be more powerfull by
> > > > > > > implementation
> > > > > > > of
> > > > > > > method like "importXML" and "exportXML".
> > > > > > >
> > > > > > > What do you think of a feature like that ?
> > > > > > >
> > > > > > > What I try to avoidby using that is BMP , TopLink/Castor,
> > > > XML/Object
> > > > > > > Databases.
> > > > > > >
> > > > > > > Vincent.
> > > > > > >
> > > > > > >
> > > > > > > _______________________________________________
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