java.lang.ClassCastException

[nacho2004]

Hi,
I've 2 beans one-one relationships
and this piece of code

InitialContext ctx = new InitialContext();
SDocuments myBean = getHome().create();
Collection col = myBean.getAllDocumentByCategoryId(11);
Iterator iter = col.iterator();
while (iter.hasNext()) {
EDocuments element = ((EDocuments) iter.next());
System.out.println("Abstract:" + element.getShortabstract());
EDocMetaData metaData = element.getDocMetaData(); System.out.println("Rawtext:" + metaData.getRawtext());
}
} catch (NamingException e) {
e.printStackTrace();
}

in the bold line this error appear:
java.lang.ClassCastException at com.Entrieva.Skyline.EntityBeans.EDocumentsCMP$Proxy.getDocMetaData()


the ejb-jar relationships is :
<!-- Relationships -->

<ejb-relation >
<ejb-relation-name>EDocuments-EDocMetaData</ejb-relation-name>

<ejb-relationship-role >
<ejb-relationship-role-name>EDocuments-has-one-EDocMetadata</ejb-relationship-role-name>
One
<relationship-role-source >
<ejb-name>EDocuments</ejb-name>
</relationship-role-source>
<cmr-field >
<cmr-field-name>docMetaData</cmr-field-name>
</cmr-field>
</ejb-relationship-role>

<ejb-relationship-role >
<ejb-relationship-role-name>EDocMetadata-has-one-EDocuments</ejb-relationship-role-name>
One
<relationship-role-source >
<ejb-name>EDocMetaData</ejb-name>
</relationship-role-source>
<cmr-field >
<cmr-field-name>documents</cmr-field-name>
</cmr-field>
</ejb-relationship-role>

</ejb-relation>

[sesques]

Hi,

Post your code and jbosscmp-jdbc.xml.
Also the full error log.

Pascal

[nacho2004]

<ejb-relation>
<ejb-relation-name>EDocuments-EDocMetaData</ejb-relation-name>
<foreign-key-mapping/>
<ejb-relationship-role>
<ejb-relationship-role-name>EDocuments-has-one-EDocMetadata</ejb-relationship-role-name>
<key-fields/>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>EDocMetadata-has-one-EDocuments</ejb-relationship-role-name>
<key-fields>
<key-field>
<field-name>docid</field-name>
<column-name>docid</column-name>
</key-field>
</key-fields>

</ejb-relationship-role>
</ejb-relation>

[sesques]

Hi,

Your relation defined as a one-one looks like a one-many.
The ClassCastException can occur if the result is a collection, not a single row.
Try to define your relation as a one-many, with a collection as return type of the getter.

Pascal

[nacho2004]

do you have any document to implement a one-to-one relationships
I think the @ejb.relation is good in both case (2 beans) but I can't understand why I can't call one bean to other by getDocidMetaData() method.
thanks in advance

[sesques]

Your relation is a good one.
I tell you the problem can occurs if the result of the query (managed by the container for the relationship) is a multi-row instead of a single row.
Do you have potentially many EDocMetaData for one EDocuments ?
In this case, your relation MUST BE a one-many.
With the informations you give, this is the only problem I think about.
I ask you to post your code and the whole descriptors, not only a snippet.
But you cannot set a one-one relationship if it is a many-one in reality.

Seems more clear ?

Pascal

[nacho2004]

But in my case both tables contain the same amount of row
And the data model for those tables is one-to-one relationships

[john_anderson_ii]

I don't know very much about CMR, I'm learning that now. But I think the ClassCastException could possibly come from these lines:

Collection col = myBean.getAllDocumentByCategoryId(11);
-----SNIP ------------

EDocuments element = ((EDocuments) iter.next());


Unless you can guaruntee that every item in the collection returned by getAllDocumentsByCategoryId is of type Edocuments, or can be cast to type Edocuments.