What objects are in my returned query list?

tjholmes · **Joined:** Thu Jul 21, 2005 10:28 am **Posts:** 21

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Hibernate version: 3.0.5

Mapping documents:

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

   <class
      name="com.starwood.saratoga.dataaccess.dvo.AgentMessageDVO"
      table="CCC.AGNT_MSG">

      <id name="id" type="long">
         <column name="MSG_ID" sql-type="NUMBER" />
            <generator class="sequence">
            <param name="sequence">CCC.SEQ_AGNT_MSG</param>
         </generator>
      </id>

      <set name="recipients" cascade="save-update">
         <key column="MSG_ID" />
         <one-to-many class="com.starwood.saratoga.dataaccess.dvo.MessageRecipientDVO" />
      </set>

      <property name="fromDate" type="date">
         <column name="MSG_START_DATE" sql-type="DATE" not-null="false" />
      </property>

      <property name="toDate" type="date">
         <column name="MSG_END_DATE" sql-type="DATE" not-null="false" />
      </property>
      
      <property name="messageText" type="string">
         <column name="MSG_TEXT" sql-type="VARCHAR2(500)" not-null="false" />
      </property>

      <property name="createUser" type="string">
         <column name="CREATE_USER_ID" sql-type="VARCHAR2(20)"
            not-null="false" />
      </property>

      <property name="createDate" type="date">
         <column name="CREATE_DATE" sql-type="DATE" not-null="false" />
      </property>

      <property name="modUser" type="string">
         <column name="UPDATE_USER_ID" sql-type="VARCHAR2(20)"
            not-null="false" />
      </property>

      <property name="modDate" type="date">
         <column name="UPDATE_DATE" sql-type="DATE" not-null="false" />
      </property>

      <property name="categoryCode" type="string">
         <column name="MSG_CATG_CD" sql-type="VARCHAR2(20)" not-null="false" />
      </property>

      <property name="behaviorCode" type="string">
         <column name="MSG_BHVR_CD" sql-type="VARCHAR2(20)" not-null="false" />
      </property>

      <many-to-one name="messageCategoryDVO" column="MSG_CATG_CD"  class="com.starwood.saratoga.dataaccess.dvo.MessageCategoryDVO" not-null="true" insert="false" update="false"/>
      <many-to-one name="messageBehaviorDVO" column="MSG_BHVR_CD"  class="com.starwood.saratoga.dataaccess.dvo.MessageBehaviorDVO" not-null="true" insert="false" update="false"/>   

   </class>

</hibernate-mapping>

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping
PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

   <class
      name="com.starwood.saratoga.dataaccess.dvo.MessageRecipientDVO"
      table="CCC.MSG_RECIPIENT">

      <composite-id>
         <key-many-to-one name="myParent" class="com.starwood.saratoga.dataaccess.dvo.AgentMessageDVO">
            <column name="MSG_ID"/>
         </key-many-to-one>
         <key-property name="recipientId" type="string" column="RECIPIENT_ID" />
      </composite-id>

      <property name="receiverCategoryCode" type="string">
         <column name="RCVR_CATG_CD" sql-type="VARCHAR2(20)" not-null="true" />
      </property>

      <many-to-one name="myParent"   column="MSG_ID"        class="com.starwood.saratoga.dataaccess.dvo.AgentMessageDVO" not-null="true"     insert="false" update="false" />
      <many-to-one name="recvCatgCd" column="RCVR_CATG_CD"  class="com.starwood.saratoga.dataaccess.dvo.ReceiverCategoryDVO" not-null="true" insert="false" update="false"/>

   </class>

</hibernate-mapping>

Name and version of the database you are using: Oracle 9i

The mapping works fine, and I have matching POJO's. I can put data into the Oracle database with no problems.

So, here I have a parent/child relationship. Some data for the record is in the parent and the other data is in the child table. With the query code I do get some records, and all is well there. I can see I am getting a Collection of records.

The question is ... what exactly am I getting back? A JDBC Query recordset? A collection of "AgentMessageDVO" classes? A hashmap? When I look at my collection that I got back, I can iterate through my records and each one says that it is a java.lang.Object ... but which object?

I'd like to iterate through each object in the collection and cast it as something else, but if I don't know what is in the list, then I can't cast it correctly or I get a classcastexception.

Any help would be much appreciated.

Code:

   public Collection findByCriteria(HashMap criteria) throws InfrastructureException {
      logger.debug("findByCriteria: start");
      String sql = getMessageCriteria(criteria);
      sql = "select {m.*},{r.*} from AGNT_MSG {m}, MSG_RECIPIENT {r} WHERE {m}.MSG_ID = {r}.MSG_ID " +
            " AND ( ({m}.MSG_START_DATE >= TO_DATE(:fromDate,'mm/dd/yy')) " +
            " AND ({m}.MSG_END_DATE <= TO_DATE(:toDate,'mm/dd/yy')) ) " +
            " AND ( ({r}.RECIPIENT_ID LIKE :recipientId ) OR ({r}.RECIPIENT_ID LIKE :roleSelected ) ) ";
      Collection messages;
      try {
         logger.debug("findByCriteria: get messages");
         Session session = HibernateUtil.getSession();
         Query qry = session.createSQLQuery(sql)
            .addEntity("m",AgentMessageDVO.class)
            .addEntity("r",MessageRecipientDVO.class)
            .setParameter("fromDate","07/01/2005")
            .setParameter("toDate","07/10/2005")
            .setParameter("recipientId","%wpsadmin%")
            .setParameter("roleSelected","%CCC_ADMIN%");
         messages = qry.list();
      } catch (HibernateException ex) {
         logger.debug("findByCriteria: HibernateException: " + ex.getMessage());
         throw new InfrastructureException(ex);
      } catch (Exception e) {
         logger.debug("findByCriteria: Exception: " + e.getMessage());
         throw new InfrastructureException(e);
      }
      logger.debug("findByCriteria: finish: return messages");
      return messages;
   }   

pksiv · **Posted:** Mon Aug 01, 2005 3:06 pm

select {m.*},{r.*}

Because of the above statement, you will get a collection of Object[] types. Object[0] will be an AgentMessageDVO and Object[1] should be a MessageRecipientDVO instance.

This is covered in section 11.4 of the reference docs if you want to read more about it.

jdl · **Joined:** Thu May 26, 2005 2:08 pm **Posts:** 99

Code:

Iterator i = messages.iterator();
while (i.hasNext()) {
    Object[] obj[] = (Object[]) i.next();
    AgentMessageDVO agentMessageDVO = (AgentMessageDVO) obj[0];
    MessageRecipientDVO messageRecipientDVO = (MessageRecipientDVO) obj[1];
    
    // ... do whatever

}

jdl · **Joined:** Thu May 26, 2005 2:08 pm **Posts:** 99

Edit to above: obj[] should just be objArray or whatever. It was a typo.

pksiv answered it while I was replying and gave you a better, more general answer.

I would highly recommend running your code in a debugger so you can see what's happening. You can learn a lot about Hibernate in a short amount of time that way.

Basilio · **Posted:** Thu Aug 04, 2005 5:55 pm

I am having such a behaviour with Criteria API. I have two different classes mapped to the same table. Criteria was created to request one of them.

Simplified mappins:

Map1:

Code:

 <class name="Account" table="account">
        <id name="accountId" column="ACCOUNT_ID" type="java.lang.Integer">
            <generator class="native"/>
        </id>
        <property name="balance" column="BALANCE" />
</class>

Map2:

Code:

<class name="SearchAccount" table="account">

  <id name="accountId" column="ACCOUNT_ID" type="java.lang.Integer">
  <generator class="native"/>
</id>

  <property name="balance" column="BALANCE" />

  <one-to-one name="account" class="AjDataAccount" />

<set name="customers" lazy="true" order-by="ACCOUNT_ID">
  <key column="ACCOUNT_ID" />
  <one-to-many class="customer" />
</set>

</class>

I am trying to find account by ID and have built Criteria object for that:

Code:

search = session.createCriteria(SearchAccount.class).add(Expression.eq("accountId", accountId));

Collection accounts = search.list();

Collection accounts will contain one object and it will be Object[] with two elements Object[0] is Account object and Object[1] will be SearchAccount. Why I have array if I have requested specific type(class) of instance?

This code was working in H2 and does not work in H3. I have tried that in H3.0.5 and H3.1b. Same result.

I much appriciate if somebody can point me on docs part related to that.

Thank you