Re: help with non decomposed M:N

Ramzi Oueslati wrote:
> Hi Armin,
> 
> Thank you for your reply. Sure I can and here it is.
> 
> This is when I try to update an already persisted instance of A :
> 
> java.lang.NullPointerException
>    at 
> org.apache.ojb.broker.metadata.DescriptorRepository.getDescriptorFor(DescriptorRepository.java:409) 
> 
>    at 
> org.apache.ojb.broker.core.MtoNBroker.getMtoNImplementor(MtoNBroker.java:129) 
>

Think I got your problem. The NPE is caused by a invalid mapping.

Your look like:

<collection-descriptor name="cs" 
collection-class="org.apache.ojb.broker.util.collections.ManageableArrayList"
        element-class="my.test.business.C"
        auto-retrieve="false" auto-update="link"
        indirection-table="TBLAC">
        <fk-pointing-to-this-class column="A_ID" />
        <fk-pointing-to-element-class column="C_ID" />
</collection-descriptor>


a correct mapping look like:

<collection-descriptor name="authors" 
element-class-ref="org.apache.ojb.broker.sqlcount.BaseCountTest$Author"
         indirection-table="SQLCOUNT_PUBLICATION"
         proxy="true"
         auto-retrieve="true"
         auto-update="object"
         auto-delete="object"
         >
         <fk-pointing-to-this-class column="MEDIUM_ID"/>
         <fk-pointing-to-element-class column="AUTHOR_ID"/>
     </collection-descriptor>
</class-descriptor>

as you can see it differs in one attribute, you use "element-class" 
instead of "element-class-ref" and this cause the NPE.

By the way, it's recommended to use the latest version of OJB (1.0.4).

Good luck!
regards,
Armin