Problems when trying to delete an object

[Bradlex]

Hello,

(Versions : Spring 1.0.2; Hibernbate 2.1; Oracle 8.1.7)

I got a problem while trying to delete an instance of type 'Periode' : the first time i try, i got a DataAccessException because there are instances of 'InfosVentes' which are linked to instances of 'Articles' which belongs to the instance of 'Periode' i want to delete > normal and expected behaviour : i catch it and display a usr-friendly warning message.

But when i try again to delete the periode (or any other) again, i got a tomcat error message with the following stacktrace :

java.lang.NullPointerException
	oracle.jdbc.driver.OraclePreparedStatement.processCompletedBindRow(OraclePreparedStatement.java:1581)
	oracle.jdbc.driver.OraclePreparedStatement.addBatch(OraclePreparedStatement.java:8540)
	org.apache.commons.dbcp.DelegatingPreparedStatement.addBatch(DelegatingPreparedStatement.java:257)
	org.apache.commons.dbcp.DelegatingPreparedStatement.addBatch(DelegatingPreparedStatement.java:257)
	net.sf.hibernate.impl.BatchingBatcher.addToBatch(BatchingBatcher.java:30)
	net.sf.hibernate.persister.EntityPersister.delete(EntityPersister.java:583)
	net.sf.hibernate.impl.ScheduledDeletion.execute(ScheduledDeletion.java:29)
	net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2438)
	net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2396)
	net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2260)
	com.match.ventestrad.dao.hibernate.ObjectDAOImpl$2.doInHibernate(ObjectDAOImpl.java:78)
	org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:150)
	com.match.ventestrad.dao.hibernate.ObjectDAOImpl.delete(ObjectDAOImpl.java:75)
	com.match.ventestrad.dao.hibernate.PeriodeDAOImpl.delete(PeriodeDAOImpl.java:91)
	com.match.ventestrad.service.PeriodeService$7.doInTransaction(PeriodeService.java:136)
	org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:114)
	com.match.ventestrad.service.PeriodeService.deletePeriode(PeriodeService.java:133)
	com.match.ventestrad.web.actions.GererPeriodesAction.perform(GererPeriodesAction.java:71)
	org.apache.struts.action.ActionServlet.processActionPerform(ActionServlet.java:1787)
	org.apache.struts.action.ActionServlet.process(ActionServlet.java:1586)
	org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:492)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:743)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:856)

Does anyone can help me and tell me what's wrong in my code and why 2nd try doesn't behave as first? (code and mapping below)
Thanks in advance

Mapping :

<class name="Periode" table="periode">
  <id name="id" column="id_periode" type="integer" unsaved-value="null">
    <generator class="sequence">
      <param name="sequence">seq_periode</param>
    </generator>
  </id>
  <property name="libelle" column="lc_libelle" type="string" />
  <property name="dateDebut" column="da_date_debut" type="date" />
  <property name="dateFin" column="da_date_fin" type="date" />
  <property name="visibleMags" column="fl_visible_mag" type="boolean" />
  <bag name="articles" table="article" lazy="true" inverse="true" cascade="all-delete-orphan" order-by="co_sous_secteur, co_code">
    <key column="id_periode" />
    <one-to-many class="Article" />
  </bag>
</class>
	
<class name="Article" table="article">
  <id name="id" column="id_article" type="integer" unsaved-value="null">
    <generator class="sequence">
      <param name="sequence">seq_article</param>
    </generator>
  </id>
  <property name="code" column="co_code" type="string" />
  <property name="libelle" column="ll_libelle" type="string" />
  <many-to-one name="sousSecteur" column="co_sous_secteur" class="SousSecteur" cascade="none" outer-join="true" />
  <many-to-one name="periode" column="id_periode" class="Periode" cascade="none" outer-join="true" />
</class>

<class name="InfoVentes" table="info_ventes">
  <id name="id" column="id_info_ventes" type="integer" unsaved-value="null">
    <generator class="sequence">
      <param name="sequence">seq_info_ventes</param>
    </generator>
  </id>
  <property name="qteLivree" column="nb_qte_livree" type="integer" />
  <property name="qteVendue" column="nb_qte_vendue" type="integer" />
  <property name="qtePerdue" column="nb_qte_perdue" type="integer" />
  <property name="qteRecomm" column="nb_qte_preconisee" type="integer" />
  <property name="site" column="id_site" type="integer" />
  <many-to-one name="article" column="id_article" class="Article" cascade="none" outer-join="true" />
</class>

public class PeriodeService {
  public void deletePeriode(final Periode periode) throws ServiceException {
    TransactionTemplate template = new TransactionTemplate(ptm);
    template.execute(new TransactionCallback() {
      public Object doInTransaction(TransactionStatus status) {
        try {
          periodeDAO.delete(periode);
          return null;
        }
        catch (DataAccessException e) {
          throw new ServiceException("DELETE FAILED", e);
        }
      }
    });
  }
}

public class PeriodeDAOImpl implements PeriodeDAO {
  public void delete(final Object obj) throws DataAccessException {
    hibernateTemplate.execute(new HibernateCallback() {
      public Object doInHibernate(Session session) throws HibernateException {
        session.delete(obj);
        session.flush();
        return null;
      }
    });
  }
}

[rhasselbaum]

This is almost certainly a Hibernate/JDBC problem, not a Spring one. Try the Hibernate forum:

http://forum.hibernate.org/

Having said that, make sure you're not trying to reuse the Hibernate session that caused the rollback.

[Bradlex]

Maybe it's a stupid question but : how can i be sure i'm not reusing the same session? :?:

[rhasselbaum]

Whatever method is retrying the operation should be outside of the transaction and session scope, and it shouldn't reuse existing persistent object instances. This is covered in the Hibernate manual:

http://www.hibernate.org/hib_docs/re...ata-exceptions

How you determine the scope of a transaction/session depends on how you've set up Hibernate and Spring, so I can't answer that.

[Bradlex]

Thanks for your help rhasselbaum!
It works fine with this code :

public class PeriodeDAOImpl implements PeriodeDAO { 
  public void delete(final Object obj) throws DataAccessException { 
    hibernateTemplate.execute(new HibernateCallback() { 
      public Object doInHibernate(Session session) throws HibernateException { 
        session.reconnect();  //added line
        session.delete(obj); 
        session.flush(); 
        return null; 
      } 
    }); 
  } 
}

[Bradlex]

oups! :oops:
I didn't look the error message carefully : it doesn't work > message says that "session is already connected" so it can't reconnect...

So that doesn't solve my problem but I think solution is near...

[rhasselbaum]

Reconnecting the session is not discarding it. You should not try to continue using the session. Please read the manual.

[Bradlex]

The problem is while using 'Hibernate Template', I have no real visibility on session lifecycle (I have no 'session.open()' and 'session.close()' or equivalent methods in my code... everything is supposed to be handle by HibernateTemplate)

[rhasselbaum]

The problem is while using 'Hibernate Template', I have no real visibility on session lifecycle (I have no 'session.open()' and 'session.close()' or equivalent methods in my code... everything is supposed to be handle by HibernateTemplate)

Right, so at a minimum, the session lifecycle is the duration of the call to HibernateTemplate. But, if you're using TransactionProxyFactoryBean or some other construct that opens a thread-local session, the lifecycle starts earlier and ends later. Although you don't open and close the session yourself, it's important to understand its scope. Typically, if you're using TransactionProxyFactoryBean the session scope is the same as the transaction's.

[Bradlex]

OK. Thanks for your help; I have not enough time to go further this way so I will add some code that will check for linked objects before deleting the 'Periode' object. Sure it is not the best and 'cleanest' solution to my problem but, at least, it will fix it till i got more time to fix it properly...

thanks again rhasselbaum.