Hi Jim,
Yes you need to change the input XML, which must contain the "foo"
reference:
It should look something like the following:
<foo id="42">
<bar foo="42">
<greeting>hello world</greeting>
</bar>
</foo>
When you marshal from Castor you'll see that Castor creates the XML like
this.
Currently this is the only way to get Castor to automatically put the
Foo parent instance into Bar.
In the future we may have something that will do it automatically
something as simple as:
<field name="##parent"/>
Is all that is really needed...
But for now, you need to use ID/IDREF.
--Keith
Jim Otte wrote:
>
> Keith,
> Thanks again for your suggestions. I tried your ideas-
> and have found:
> 1. I listed the identity=id in the <class> element of
> Foo - and the parent field under Bar as <bind-xml
> node="attribute" reference="true" /> yet I still do
> not get the expected result- just a null pointer when
> referencing the parent fields.
> Does the input xml have to change at all- I have
> changed only the mapping xml- or the classes?
> I need to have Bar as a child of Foo so I need to have
> an element for Bar:
> <field name="bar" type="Bar">
> <bind-xml name="bar"
> node="element"/>
> </field>
>
> or else Castor complains :
> unable to find FieldDescriptor for 'bar' in
> ClassDescriptor of foo
>
> for the xml....So am I just not seeing something here
> or is it still a limitation for a relation such as
> this?
>
> Thanks for your input,
> Jim
>
> --- Keith Visco <[EMAIL PROTECTED]> wrote:
> >
> >
> >
> > Jim Otte wrote:
> > >
> > > Keith,
> > >
> > > Thanks for the lead- I believe that is the right
> > > trail- however, when I implement the ID/IDREF
> > > attributes- I still do not get the reference to
> > the
> > > parent from the child - note my differences from
> > your
> > > example:
> > > 1. The Parent Foo has the child Bar class as an
> > > attribute: Foo has Bar bar; as a class member.
> >
> > Yes...that's understood...I saw the classes you
> > listed in your original
> > post. When using ID/IDREF however you have to mark
> > them in the
> > mapping file as attributes. This is a limitation on
> > ID/IDREF and
> > the limitation comes from DTDs. ID/IDREF must be
> > specified as
> > attributes in the XML instance.
> >
> > > 2. It is not necesarily the case that Bar extends
> > Foo
> > > (am not certain if that is what was being
> > understood)-
> > > Bar should just be a child class attribute with a
> > > reference to the parent- no special relation
> > outside
> > > of that.
> >
> > Yes...no misunderstanding here. My example
> > demonstrates a simple
> > parent-child relationship.
> >
> > > 3. It is possible that Foo may have more than 1
> > field
> > > as "ID" or primary -key.
> >
> > Castor doesn't yet have the ability to support
> > multiple
> > fields as the key (actually it doesn't support
> > key/keyref yet)
> >
> > You can work around this limitation by providing one
> > field that
> > incorporates both keys such as:
> >
> > public String getIdentity() {
> > return key1 + "," + key2;
> > }
> >
> > > 4. The parent reference is a type node="element"
> > > rather than "attribute"- although I get the same
> > > result even if I do switch that:
> > > Nevertheless- when I use the following mapping:
> >
> > Both the identity field and the reference field need
> > to be marked as
> > attributes.
> >
> > --Keith
> >
> >
> > >
> > > <class name="tudo.foobar.castor.domain.Foo"
> > > identity="id">
> > > <map-to xml="foo"/>
> > >
> > > <field name="id"
> > > type="java.lang.String" >
> > > <bind-xml name="id"
> > > node="element"/>
> > > </field>
> > >
> > > <field name="bar" type="Bar">
> > > <bind-xml name="bar"
> > > node="element"/>
> > > </field>
> > > </class>
> > >
> > > <class name="Bar" >
> > > <map-to xml="bar"/>
> > >
> > > <field name="greeting"
> > > type="java.lang.String">
> > > <bind-xml name="greeting"
> > > node="element"/>
> > > </field>
> > >
> > > <field name="parent" type="Foo" >
> > > <bind-xml name="foo"
> > > reference="true" />
> > > </field>
> > > </class>
> > >
> > > with the classes:
> > > public class Foo {
> > > public Bar bar;
> > > public String id;
> > >
> > > and
> > >
> > > public class Bar{
> > >
> > > public String greeting;
> > > public Foo parent;
> > >
> > > and xml:
> > > <foo>
> > > <id>42</id>
> > > <bar>
> > > <greeting>hello world</greeting>
> > > </bar>
> > > </foo>
> > >
> > > and run the test with:
> > >
> > > System.out.println(foo.getBar().getGreeting());
> > >
> > >
> >
> System.out.println(foo.getBar().getParent().getId());
> > >
> > > I would expect:
> > >
> > > hello world
> > > 42
> > >
> > > Instead I still get:
> > >
> > > hello world
> > > java.lang.NullPointerException
> > >
> > > The Child Bar class does not seem to get a
> > reference
> > > to the parent Foo even using the ID and IDREF
> > > tags....although I may very well be mis-applying
> > them.
> > >
> > > Any further thoughts/corrections would be most
> > > welcome-
> > > Thanks again for the help- I have been racking my
> > > brains on this for quite awhile....
> > >
> > > Jim
> > >
> > > --- Keith Visco <[EMAIL PROTECTED]> wrote:
> > > >
> > > >
> > > > Jim,
> > > >
> > > > Castor supports parent-child relationships via
> > > > ID/IDREF and can be
> > > > expressed as such in a mapping file:
> > > >
> > > >
> > > > <class name="Foo" identity="id">
> > > > <field name="id" type="string"/>
> > > > </class>
> > > >
> > > > <class name="Bar">
> > > > <field name="parent" type="Foo">
> > > > <bind-xml node="attribute"
> > reference="true"/>
> > > > </field>
> > > > </class>
> > > >
> > > > Note the identity="id" specified on the Foo
> > class
> > > > mapping. And also note
> > > > the reference="true" specified on the bind-xml
> > > > element for the parent
> > > > field in the Bar class mapping.
> > > >
> > > >
> > > > I hope that helps.
> > > >
> > > > --Keith
> > > >
> > > > Jim Otte wrote:
> > > > >
> > > > > Ralf,
> > > > >
> > > > > Thanks for your reply!
> > > > > I tried your suggestion- by modifying the
> > domain
> > > > > objects Foo and Bar- Now when I run the test
> > class
> > > > I
> > > > > get the following error:
> > > > >
> > > > > org.xml.sax.SAXException: unable to add 'bar'
> > to
> > > > <foo>
> > > > > due to the following exception:
> > > > > >>>--- Begin Exception ---<<<
> >
> === message truncated ===
>
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