EJB2.0 issue on weblogic server 8.1 sp4

Question

We are doing some ejb2.0 development on weblogic 8.1 sp4, and We have noticed some unusual and undesirable behavior with CMR.
The following session bean code is used to define a Many-Many relationship between different entity beans in the same EJB using CMR.
The method does the following:
1. Gets the existing Collection of parents EJBs for the child EJB.
2. Checks that the new parent EJB is not in the existing parents Collection
3. Adds the new parent to the Collection and finally sets the parents Collections for the child EJB.
public static void addChild(EntityHandle a_parent, EntityHandle a_child)
throws TrackingException
TrackedEntityLocal parent = null;
TrackedEntityLocal child = null;
parent = getEntity(a_parent);
child = getEntity(a_child);
Collection parents = child.getParents();
if (!containsEJB(parents, parent)) // return true if parent already exists in collection parents.
parents.add(parent);
child.setParents(parents);
In the problem scenario we are creating the child and its parent entities in the same transaction.
We then define the raltionships by adding parents to the same child EJB on the client side within the same transaction (that created the EJBs) like this:
addChild( parentOne, child);
addChild( parentTwo, child);
addChild( parentThree, child);
I expect 3 records in the CMR EJB table entity_relationship but I end up with 6 records in table entity_relationship like this.
parentOne,child
parentOne,child
parentTwo,child
parentOne,child
parentTwo,child
parentThree,child
What seems to be happening is that these EJB relationships are being duplicated in the EJB cache which means that when the container persists the relationships it breaks a unique constraint that is defined in Oracle.
It seems that each time I call child.getParents() I get a copy of the bean's current parent relationships in the cache (which I then add one new parent to).
Even though I set the parent Collection back into the bean (which i would expect to replace the existing Collection) at persist time the container seems to attempt to persist 3 distinct Collections.
We only seem to get this problem if the parent entity itself has not yet been persisted.
If the parent EJBs have already been created in table entity beforehand, we only get 3 relationships in table entity_relationship.
parentOne,child
parentTwo,child
parentThree,child
Anybody has any idea what's going on here? thanks a million.
EJB schema below:
both parent and child are from one table:entity.
CREATE TABLE entity
( id INTEGER NOT NULL PRIMARY KEY,
type_id INTEGER NOT NULL
CONSTRAINT entity_FK
REFERENCES entity_type(id),
orig_comp_id INTEGER NOT NULL
CONSTRAINT entity_FK2
REFERENCES component(id)
entity_relationship defines the relation between parent and child
CREATE TABLE entity_relationship
( end1_id INTEGER NOT NULL
CONSTRAINT entity_relationship_FK
REFERENCES entity(id),
end2_id INTEGER NOT NULL
CONSTRAINT entity_relationship_FK2
REFERENCES entity(id),
type_id INTEGER DEFAULT(1)
NOT NULL
CONSTRAINT entity_relationship_FK3
REFERENCES entity_rel_type(id),
CONSTRAINT entity_relationship_PK PRIMARY KEY(end1_id,end2_id,type_id)
EJB descriptors given below:
============================================ejb-jar.xml===============================================
<entity>
<ejb-name>TrackedEntityEJB</ejb-name>
<local-home>uk.police.pnn.psni.eai.bcomp.tracking.entity.TrackedEntityHomeLocal</local-home>
<local>uk.police.pnn.psni.eai.bcomp.tracking.entity.TrackedEntityLocal</local>
<ejb-class>uk.police.pnn.psni.eai.bcomp.tracking.entity.TrackedEntityBean</ejb-class>
<persistence-type>Container</persistence-type>
<prim-key-class>java.lang.Integer</prim-key-class>
<reentrant>False</reentrant>
<cmp-version>2.x</cmp-version>
<abstract-schema-name>entity</abstract-schema-name>
<cmp-field>
<field-name>id</field-name>
</cmp-field>
<primkey-field>id</primkey-field>
<security-identity>
<use-caller-identity/>
</security-identity>
</entity>
<ejb-relation>
<ejb-relation-name>entity-entity</ejb-relation-name>
<ejb-relationship-role>
<ejb-relationship-role-name>Entity-has-Parents</ejb-relationship-role-name>
<multiplicity>Many</multiplicity>
<relationship-role-source>
<ejb-name>TrackedEntityEJB</ejb-name>
</relationship-role-source>
<cmr-field>
<cmr-field-name>parents</cmr-field-name>
<cmr-field-type>java.util.Collection</cmr-field-type>
</cmr-field>
</ejb-relationship-role>
<ejb-relationship-role>
<ejb-relationship-role-name>Entity-has-Children</ejb-relationship-role-name>
<multiplicity>Many</multiplicity>
<relationship-role-source>
<ejb-name>TrackedEntityEJB</ejb-name>
</relationship-role-source>
<cmr-field>
<cmr-field-name>children</cmr-field-name>
<cmr-field-type>java.util.Collection</cmr-field-type>
</cmr-field>
</ejb-relationship-role>
</ejb-relation>
<container-transaction>
<method>
<ejb-name>TrackedEntityEJB</ejb-name>
<method-name>*</method-name>
</method>
<trans-attribute>Supports</trans-attribute>
</container-transaction>
==========================weblogic-ejb-jar.xml===================================================
<weblogic-enterprise-bean>
<ejb-name>TrackedEntityEJB</ejb-name>
<entity-descriptor>
<persistence>
<persistence-use>
<type-identifier>WebLogic_CMP_RDBMS</type-identifier>
<type-version>6.0</type-version>
<type-storage>META-INF/weblogic-cmp-rdbms-jar.xml</type-storage>
</persistence-use>
</persistence>
</entity-descriptor>
<enable-call-by-reference>true</enable-call-by-reference>
<local-jndi-name>bcomp.tracking.entity.TrackedEntityHomeLocal</local-jndi-name>
</weblogic-enterprise-bean>
=============================weblogic-cmp-rdbms-jar.xml==========================================
<weblogic-rdbms-relation>
<relation-name>entity-entity</relation-name>
<table-name>entity_relationship</table-name>
<weblogic-relationship-role>
<relationship-role-name>Entity-has-Parents</relationship-role-name>
<relationship-role-map>
<column-map>
<foreign-key-column>end2_id</foreign-key-column>
<key-column>id</key-column>
</column-map>
</relationship-role-map>
</weblogic-relationship-role>
<weblogic-relationship-role>
<relationship-role-name>Entity-has-Children</relationship-role-name>
<relationship-role-map>
<column-map>
<foreign-key-column>end1_id</foreign-key-column>
<key-column>id</key-column>
</column-map>
</relationship-role-map>
</weblogic-relationship-role>
</weblogic-rdbms-relation>
Edited by: user10185877 on 26-Aug-2008 02:06

Answer 1

I am also wondering what the status of this problem is? It is preventing us from going to SP4.
_Mike