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From Christophe Lombart <christophe.lomb...@gmail.com>
Subject Re: [mapping] mapping enhancement supporting GRFT54
Date Mon, 16 Jan 2006 21:01:31 GMT
Well, honnestly I don't remember the complete discussion.

So what are all the improvements you are looking for ?
1. the GRFT-54 support - Are there other similar improvements ?
2. inheritance
3. Spread (?)
4. ??

What about the converter, did you check the collection converter ? is
it fit your needs ?




On 1/16/06, Alexandru Popescu <the.mindstorm.mailinglist@gmail.com> wrote:
> #: Christophe Lombart changed the world a bit at a time by saying (astral date: 1/16/2006
9:48 PM) :#
> > On 1/16/06, Alexandru Popescu <the.mindstorm.mailinglist@gmail.com> wrote:
> >> #: Christophe Lombart changed the world a bit at a time by saying (astral date:
1/16/2006 5:25 PM) :#
> >> > Concerning issue http://issues.apache.org/jira/browse/GRFT-54,
> >> > Why do you think about the following mapping  :
> >> >
> >> > <class-descriptor className="xxx.File" jcrNodeType="nt:file" >
> >> >         <field-descriptor fieldName="path" path="true" />
> >> >         <subnode-descriptor   jcrName="jcr:content" ... >
> >> >             <field-descriptor fieldName="mimeType" jcrName="jcr:mimeType"
... />
> >> >             <field-descriptor fieldName="encoding"
> >> > jcrName="jcr:encodiging" .../>
> >> >             <field-descriptor fieldName="data" jcrName="jcr:data" ...
/>
> >> >             ....
> >> >         </subnode-descriptor>
> >> > </class-desciptor>
> >> >
> >> > the "subnode-descriptor" is there to create a new subnode called
> >> > "jcr-content" which will contains some object attributes like
> >> > mimeType, encoding, ...
> >> >
> >> > Anyway, I like the "converter" idea. At least, it quite easy to
> >> > implement it for the fd.
> >> > Converters for cd already exists but they need to be review. But now,
> >> > we have to think about how to use the converters for the bd.
> >> >
> >> > (I don't speak now on inheritance, we can start this discussion later).
> >> >
> >>
> >> The proposal you are making is quite nice for this particular example. But I
cannot say how
> >> extensible it is (by looking at it I would say that it is pretty much the bean-descriptor).
I would
> >> like that before introducing more descriptors to be sure that a new one will
be able to fill in a
> >> whole range of solutions and not just a particular one. The same applies to
the existing ones.
> >
> > ok - can we create a new jira issues which will contain all use cases.
> > It is quite difficult to remember all possibilities.
> >
> > Thanks
> >
> >
>
> Not sure what you are asking :-(. Is your question about creating a JIRA issue for each
of the
> suggested improvements? If yes, than I would say that I would prefere having it in the
ML than
> directly on JIRA, and upon concluding adding a JIRA with only the conclusion. But if
you think JIRA
> is better to handle this discussion than go ahead and open the necessary enhancement
requests.
>
> cheers,
>
> ./alex
> --
> .w( the_mindstorm )p.
>
>
> >>
> >> ./alex
> >> --
> >> .w( the_mindstorm )p.
> >>
> >> >
> >> > On 1/14/06, Alexandru Popescu <the.mindstorm.mailinglist@gmail.com>
wrote:
> >> >> #: Christophe Lombart changed the world a bit at a time by saying (astral
date: 1/13/2006 11:20 AM) :#
> >> >> > On 1/13/06, Alexandru Popescu <the.mindstorm.mailinglist@gmail.com>
wrote:
> >> >> >
> >> >> >> considering the GRFT54 example, you will write:
> >> >> >>
> >> >> >> <bean-descriptor fieldName="file"
> >> >> >>                  converterClass="NtFileConverter" />
> >> >> >>
> >> >> >> and NtFileConverter will be responsible for creating the nt:file
node structure. Same mechanism will
> >> >> >> work for fetching.
> >> >> >>
> >> >> >
> >> >> > I like this idea but how set the mapping rules for each attributes
?
> >> >> > I expect the field-descriptor, bean-descriptor & collection-descriptor
> >> >> > are still necessary if we uses the convertClass.
> >> >> >
> >> >>
> >> >> This is a very good question to which unfortunately i don't have a
good answer. While a predefined
> >> >> converter knows how to deal with a limitted set of properties/subnodes,
on the other side (e.g. on
> >> >> objects world) those properties may come from really complex expressions.
> >> >> There are a few possible approaches to solving this, but for the moment
none of them satisfies me:
> >> >> - have the object implement an interface which responds to the needs
of the converter
> >> >> (may be considered bad because it ties the object to the ojcrm tool)
> >> >> - have the description provided through the same mechanisms of fd,
bd or cd
> >> >> (may be considered bad because the mapping becomes complex, and changes
in some way the semantics of
> >> >> fd, bd and cd)
> >> >> - create/reuse a object graph navigation language
> >> >> (may be considered bad because the user should learn a new/the user
should use a new `languageĀ“)
> >> >> - have the converter provide extension points so that in special cases
an user may extend it to
> >> >> extract the values/populate the values
> >> >>
> >> >> Example:
> >> >> 1/ in the simplest case where the object provides accessors to the
object properties according to
> >> >> the needs of the converter than you don't need to detail the mapping
(the node property paths and
> >> >> subnodes paths maps directly to object properties)
> >> >> 2/ in more complex cases where the object needs special manipulation
in order to provide/to write
> >> >> object properties, than the user should extend the converter and provide
access to those properties
> >> >>
> >> >> what do you think?
> >> >>
> >> >> ./alex
> >> >> --
> >> >> .w( the_mindstorm )p.
> >> >>
> >> >>
>
>
>


--
Best regards,

Christophe

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