polymorphic and recursive collection

[LE-QUERE Gildas - REN]

Hi All,

I want to make persistent a polymorphic and recursive collection (custom
implementation).

The collection elements are instances of the A class and the B class. B
extents A.

The A class contains this collection.

UML model
=========
           ______________________
    *      |  children                             | type 1:N relationship
-------\/----------                            |
|             A           |                           |
|------------------|                           |
|  oid: int               |                           |
|  attA: String        | ----------------- 
|______________|
            /\
             |
------------------ 
|            B            |
|------------------|
|  attB: String        |
|_____________|

DATABASE SCHEMA (tested with Oracle)
===============================

create table T_A (
        attA VARCHAR ( 48 ) NULL,
        children INTEGER NULL,
        oid INTEGER NOT NULL,
        constraint PK_T_A PRIMARY KEY (oid)
)
create table T_B (
        attB VARCHAR ( 48 ) NULL,
        oid INTEGER NOT NULL,
        constraint PK_T_B PRIMARY KEY (oid)
)
-- 1:N relationship
alter table T_A add constraint FK_T_children foreign key (children)
references T_A (oid)
/
-- inheritance
alter table T_B add constraint FK_T_AB foreign key (oid) references T_A
(oid)
/

MAPPING in the repository.xml
======================

<class-descriptor class="ojb.test.A" table="T_A"
isolation-level="read-uncommitted" accept-locks="true" refresh="true" >
        <field-descriptor name="oid" column="oid" jdbc-type="INTEGER"
primarykey="true" autoincrement="true"/>
        <field-descriptor name="attA" column="attA" jdbc-type="VARCHAR"/>
        <field-descriptor name="children" column="children"
jdbc-type="INTEGER" access="anonymous" />
        <!-- lien sur les fils -->
        <collection-descriptor name="children" auto-update="true">
                <inverse-foreignkey field-ref="children"/>
        </collection-descriptor>
</class-descriptor>
<class-descriptor class="ojb.test.B" table="T_B"
isolation-level="read-uncommitted" accept-locks="true" refresh="true">
        <field-descriptor name="oid" column="oid" jdbc-type="INTEGER"
primarykey="true" autoincrement="true" />
        <field-descriptor name="attB" column="attB" jdbc-type="VARCHAR"/>
        <!-- inheritance A - B -->
        <reference-descriptor name="super" class-ref="ojb.test.A"
auto-retrieve="true" auto-delete="true" auto-update="true">
            <foreignkey field-ref="oid"/>
        </reference-descriptor>
</class-descriptor>

JAVA CODE
==========

public class A {
        private int oid;
        private String attA = null;
        private MyCollection children = null;
}

public class B extends A {
    private String attB = null;
}
public class MyCollection implements Collection {
    private Vector v = null;
}

TEST RESULT
===========

If the collection contains A element only that works fine. If the collection
contains B elements OJB doesn't see that B is a A subclass and throws an
Exception because it doesn't find the chidren foreign key. I have the
following error message:
____________________________________________________________________________
_______
org.apache.ojb.broker.OJBRuntimeException: Incorrect or not found field
reference name 'children' in descriptor
[EMAIL PROTECTED]
false,cascade_store=object,cascade_delete=none,is_lazy=false,class_of_Items=
<null>] for class-descriptor 'ojb.test.B'
____________________________________________________________________________
_______
Please can you help me.

Thanks

Gildas

---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]