Perhaps it would be better to place the field-selection list in the query
itself, as in:
Query quey = QueryFactory.newQuery(MyClass.class, critieia,
fieldsToRetrieve);
That seems more natural. Plus it would avoid breaking the existing
PersistenceBroker interface.
Michael
----- Original Message -----
From: "Michael Mogley" <[EMAIL PROTECTED]>
To: "OJB Users List" <[EMAIL PROTECTED]>
Sent: Tuesday, November 25, 2003 10:13 AM
Subject: Re: Collection of string
> I agree. IMO, this should not require any additional mapping definitions
> beyond those necessary to map the classes. It should be possible to
> arbitrarily request a collection of a specific field type from a mapped
> class, and this should be simple and easy through the API.
>
> I would even propose the ability to retrieve arbitrary subsets of a class'
> fields. E.g:
>
> Class MyClass {
> field A,
> field B,
> field C
> }
>
> It would be nice to do something like:
>
> Query query = QueryFactory.newQuery(MyClass.class, criteria);
>
> List fieldsToRetrieve = new LinkedList();
> fieldsToRetrieve.add( fieldAMetaData );
> fieldsToRetrieve.add( fieldBMetaData );
>
> Collection retrievedFields =
> persistenceBroker.getCollectionByQuery(query, fieldsToRetrieve);
>
> Here, retrievedFields would be a collection of Maps. We could then do:
>
> for (Iterator itrFields = retrievedFields.iterator();
> itrFields.hasNext();) {
> Map nextResult = (Map)itrFields.next();
>
> Object fieldA = nextResult.get("A");
> Object fieldB = nextResult.get("B");
> }
>
> Or something similar.
>
> Michael
>
> ----- Original Message -----
> From: "eric barbe" <[EMAIL PROTECTED]>
> To: "OJB Users List" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
> Sent: Tuesday, November 25, 2003 9:47 AM
> Subject: RE: Collection of string
>
>
> > Hi all,
> >
> > YES, YES, and YES, I think we need this feature ! ;o)
> > Why ?
> > First, if you want to use your database information without OJB, you can
> not
> > do simply data reporting or analysis.
> > Second, if you are coding an API that can be use with a lot of
> heterogeneous
> > projects that don't use at least OJB or a database, it is not
conceptually
> > correct to force users to use Wrapper classes.
> > Example : we are developping an API that allows to handle our kernel
> datas.
> > This API is use with a lot of projects and uses the standard java types.
> > Creating wrapper classes :
> > - will be diverting the developpers,
> > - will lost the compatibility,
> > - will be not consistant with the philosophy of Java, what is an
APIString
> > ? A string, a stringbuffer ?
> > Then you will decide to create a second API, one for the "old users" and
> one
> > for the "OJB users" and then it will be to difficult to maintain.
> >
> > In short, YES, YES, and YES, we need this feature !
> >
> > Best regards,
> >
> > Sorry for my english !!
> >
> > Eric
> >
> > -----Message d'origine-----
> > De : [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> > Envoye : mardi 25 novembre 2003 18:18
> > A : OJB Users List
> > Objet : Re: Collection of string
> >
> >
> > Hi all,
> >
> >
> > Thomas Dudziak wrote:
> > >
> > > On Tue, 25 Nov 2003, eric barbe wrote:
> > >
> > >
> > >>Hi,
> > >>
> > >>Honestly, I did not test Hibernate, I only read the documentation.
> > >>Hibernate works the other way around from OBJ for modeling the XML.
> > >>What I saw for string list is this :
> > >> <set name="names" table="NAMES">
> > >> <key column="GROUPID"/>
> > >> <element column="NAME" type="string"/>
> > >> </set>
> > >>It seem's simply. You give the "name" property, then the "table" name
> and
> > >>the field (or element here) type.
> > >>
> > >>I think that Hibernate is wrapping each java object naturally.
> > >>
> > >>Regards
> > >>
> > >>Eric
> > >>
> > >>PS : see this link
> >
>
>>http://www.hibernate.org/hib_docs/reference/html/collections.html#collecti
> > on
> > >>s-s1-3
> > >>
> > >
> > >
> > > Unless I'm mistaken this seems to be something that OJB is not capable
> of,
> > > at least not directly. In OJB, the elements of collections have to
have
> a
> > > class descriptor in the repository descriptor whereas Hibernate seems
to
> > > also have the notion of "primitive" elements.
> >
> > Yes, with OJB you would have to write a simple Wrapper class that is
> > declared as element-class in the collection-descriptor.
> >
> > questions to the users: Do we need a feature to simplify the storage of
> > primitive types?
> >
> > cu,
> > Thomas
> >
> > >
> > > Tom
> > >
> > >
> > >
> > > ---------------------------------------------------------------------
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> > >
> > >
> >
> >
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> >
> >
> >
> >
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> >
>
>
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