EJB-QL Question

[Sloan Bowman]

I am having problems with finder methods on the home interface returning the correct values. For example i have a Client entity bean setup and a Contact entity bean setup. I have a 1 to many relationship between the two, the client is the 1 and the contact is the many. I am trying to run a simple EJB-QL statement and return all Contact entity objects to work with the data. When I run the query it seems to return the right number of entity beans but they are of the wrong type so when I cast them to the proper type my application fails and throw an exception. After debuging with Eclipse it appears that the entity objects being return are Client entity beans instead of the Contact entity beans which are supossed to be returned. Below is application deployment and query.

Envionment:
AppServer: JBoss 3.2.5

EJB-QL: Select Object(co) FROM Client AS c, IN (c.contacts) AS co;

Deployment descriptors

ejb-jar.xml:

Client descriptor

      <entity >
         <description><![CDATA[Description for Client]]></description>
         <display-name>Name for Client</display-name>
 
         <ejb-name>Client</ejb-name>
 
         <local-home>com.aimanager.ejb.entity.ClientLocalHome</local-home>
         <local>com.aimanager.ejb.entity.ClientLocal</local>
 
         <ejb-class>com..aimanager.ejb.entity.ClientCMP</ejb-class>
         <persistence-type>Container</persistence-type>
         <prim-key-class>com.aimanager.ejb.entity.ClientPK</prim-key-class>
         <reentrant>False</reentrant>
         <cmp-version>2.x</cmp-version>
         <abstract-schema-name>Client</abstract-schema-name>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field clientId]]></description>
            <field-name>clientId</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field name]]></description>
            <field-name>name</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field address1]]></description>
            <field-name>address1</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field address2]]></description>
            <field-name>address2</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field city]]></description>
            <field-name>city</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field stateId]]></description>
            <field-name>stateId</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field zip]]></description>
            <field-name>zip</field-name>
         </cmp-field>
 
         <query>
            <query-method>
               <method-name>findAllClients</method-name>
               <method-params>
               </method-params>
            </query-method>
            <ejb-ql><![CDATA[SELECT OBJECT(a) FROM Client AS a WHERE a.clientId IS NOT NULL]]></ejb-ql>
         </query>
         <query>
            <query-method>
               <method-name>findClientOrders</method-name>
               <method-params>
               </method-params>
            </query-method>
            <ejb-ql><![CDATA[SELECT Object(o) FROM Client AS c, IN (c.orders) AS o]]></ejb-ql>
         </query>
         <query>
            <query-method>
               <method-name>findClientContacts</method-name>
               <method-params>
               </method-params>
            </query-method>
            <ejb-ql><![CDATA[SELECT Object(co) FROM Client AS c, IN(c.contacts) AS co]]></ejb-ql>
         </query>
  <!-- Write a file named ejb-finders-ClientBean.xml if you want to define extra finders. -->
      </entity>
 

Contact descriptor:

<entity >
         <description><![CDATA[Description for Contact]]></description>
         <display-name>Name for Contact</display-name>
 
         <ejb-name>Contact</ejb-name>
 
         <local-home>com.aimanager.ejb.entity.ContactLocalHome</local-home>
         <local>com.aimanager.ejb.entity.ContactLocal</local>
 
         <ejb-class>com.aimanager.ejb.entity.ContactCMP</ejb-class>
         <persistence-type>Container</persistence-type>
         <prim-key-class>com.aimanager.ejb.entity.ContactPK</prim-key-class>
         <reentrant>False</reentrant>
         <cmp-version>2.x</cmp-version>
         <abstract-schema-name>Contact</abstract-schema-name>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field contactId]]></description>
            <field-name>contactId</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field clientId]]></description>
            <field-name>clientId</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field isMain]]></description>
            <field-name>isMain</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field firstName]]></description>
            <field-name>firstName</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field lastName]]></description>
            <field-name>lastName</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field phone1]]></description>
            <field-name>phone1</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field phone2]]></description>
            <field-name>phone2</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field mobile]]></description>
            <field-name>mobile</field-name>
         </cmp-field>
         <cmp-field >
            <description><![CDATA[Getter for CMP Field email]]></description>
            <field-name>email</field-name>
         </cmp-field>
 
  <!-- Write a file named ejb-finders-ContactBean.xml if you want to define extra finders. -->
      </entity>
 

relationship descriptor:

<ejb-relation >
         <ejb-relation-name>Client-Contact</ejb-relation-name>
 
         <ejb-relationship-role >
            <ejb-relationship-role-name>client-has-many-contacts</ejb-relationship-role-name>
            <multiplicity>One</multiplicity>
            <relationship-role-source >
               <ejb-name>Client</ejb-name>
            </relationship-role-source>
            <cmr-field >
               <cmr-field-name>contacts</cmr-field-name>
               <cmr-field-type>java.util.Collection</cmr-field-type>
            </cmr-field>
         </ejb-relationship-role>
 
         <ejb-relationship-role >
            <ejb-relationship-role-name>contact-has-a-client</ejb-relationship-role-name>
            <multiplicity>Many</multiplicity>
            <relationship-role-source >
               <ejb-name>Contact</ejb-name>
            </relationship-role-source>
         </ejb-relationship-role>
 
      </ejb-relation>

Client Code (In a session bean)

    public Collection getContacts(ClientLocal clientLocal)
    throws ClientException
    {
        // Test to make sure the clientLocal entity bean is valid
        if(clientLocal == null)
        {
            throw new ClientException("Client reference is invalid or empty");
        }
        
        ArrayList contactList = new ArrayList();
        try
        {          
            // Get the client's local home interface
            ClientLocalHome clientLocalHome = (ClientLocalHome)clientLocal.getEJBLocalHome();
            
            // Get the contacts related to this client
            Iterator iter = clientLocalHome.findClientContacts().iterator();
            while(iter.hasNext())
            {
                ContactLocal contactLocal = (ContactLocal)iter.next();
                Contact contact = new Contact();
                contact.setContactId(contactLocal.getContactId().intValue());
                contact.setFirstName(contactLocal.getFirstName());
                contact.setLastName(contactLocal.getLastName());
                contact.setPhone1(contactLocal.getPhone1());
                contact.setPhone2(contactLocal.getPhone2());
                contact.setMobile(contactLocal.getMobile());
                contact.setEmail(contactLocal.getEmail());
                
                // Add the contactDO to the collection
                contactList.add(contact);
            }
        }
        catch(Exception e)
        {
            throw new ClientException("Unable to get contact list. Cause: " + e.getMessage());
        }
        
        // If all went well we are now returning the collection
        return(contactList);
    }

Thanks for your help. Once I get past this hurdle I think I will have a much better understanding of what I am doing wrong.

[Sloan Bowman]

For those of you interested the problem I was facing was being stupid and forgetting that finder methods only return the native local of the object. I converted these queries to select methods and used the selcts in the entity bean business method and it worked like a champ.

[Bruce Sheng]

Can you post the correct local home definition and it's deployment descriptor?