Hi Keith,
I am sorry to mention, but Castor does not do the look up; I might be wrong.
Kindly give me a hint how it does.
Thanks,
Sunil
-----Original Message-----
From: Keith Visco [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, January 08, 2002 9:09 PM
To: [EMAIL PROTECTED]
Subject: Re: [castor-dev] Castor XML - marshal/unmarshal of reference to
an object
Hi Sunil,
See the last line below...
> RACHAMADUGU Sunil wrote:
>
> I have two classes A and B. Class B has a reference to object of class
> A. Instantiating the classes into objects 'a' and 'b' respectively:
>
> a --> b (object 'b' has a reference to object 'a')
>
> I am using Castor to save these objects into XML document.
>
> Referring to earlier information in the Castor documentation and
> mailing list, I noted that
> "Castor supports references via the Source Code Generator and via the
> mapping file"
> "References are not supported via introspection"
> "We need to use the 'reference' and 'identity' in conjunction"
>
> How I am doing it:-
>
> This is how the classes appears:
>
> Class A{
> String id
> ...
> getId() {...}
> setId(String newId) {...}
> }
>
> Class B{
> ...
> reference_to_A
> ...
> getId() {...}
> setId(String newId) {...}
> getReference_to_A() {...}
> setReference_to_A(A a) {...}
>
> }
>
> Dictionary id_names // stores ids of all objects
>
> We need to use a mapping file, which uses the identity and reference
> in conjunction as follows:
> A --> identity
> B --> attribute A, reference=true
>
> A snippet from the mapping file:
>
> Mark the appropriate Identity field: (the field 'id' of class A)
>
> <class name="A" identity="id">
> ...
> <field name="id" type="string">
> <bind-xml node="attribute"/>
> </field>
> ...
> </class>
>
> Then mark references as such: (the 'reference' of <bind-xml> element
> is set as 'true' for the field 'reference_to_A')
>
> <class name="B">
> ...
> <field name=" reference_to_A" type="A">
> <bind-xml node="attribute" reference="true"/>
> </field>
> ...
> </class>
>
> During the marshalling of the objects into XML document, the reference
> to the object is stored as a string (in the mapping file, I have set
> 'reference=true' for this field).
>
> During unmarshalling..
>
> Apart from the above-mentioned accessors for the field
> 'reference_to_A', we need to add another method, which takes a
> 'String' argument. The new method looks as follows:
>
> B.setReference_to_A (String id_of_a) {
>
> Obj = Get_From_Dictionary(id_of_a) // lookup in the
> dictionary
>
> if (Obj != null) {
> Reference_to_parent_object = Obj
> }
> else {
> error // Object not found
> }
> }
>
You shouldn't need this method...Castor should do the lookup for you
automatically.
--Keith
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