Can't get active session of an eclipselink's EntityManager with spring

Question

I have a class that is responsible for execute stored procedure, it was working fine when I was using JTA... But cause I have some problems with redeploy, I removed JTA and I'm using local entity manager with spring:

 <bean id="entityManagerFactoryErp" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="persistenceUnitName" value="erpPU"/>
</bean>
<bean id="entityManagerErp" class="org.springframework.orm.jpa.support.SharedEntityManagerBean">
    <property name="entityManagerFactory" ref="entityManagerFactoryErp"/>
</bean> 

Now I get a NullPointerException when I try to get active session:

public class ExecutadorProcedimentoArmazenado extends BaseDao implements IExecutadorProcedimentoArmazenado {

    public boolean executar(String nomeProcedimento) {
        DataReadQuery query = configurarQuery(nomeProcedimento);
        registro = executarProcedimento(query);
        int resultado = Integer.parseInt(recuperarValorDeSaida("RESULTADO"));
        mensagem = recuperarValorDeSaida("MSGERRO");
        return resultado == 0;
    }
    .
    .
    private Session configurarSessao() {
        JpaEntityManager jpaEntityManager = JpaHelper.getEntityManager(entityManager);
        return jpaEntityManager.getActiveSession();
    }
    .
    .
    .
}

ADDED

Probably the problem is that entityManager doesn't have a transaction. I'm trying create the transaction with spring aop, it works for all other classes, but doesn't works for interface IExecutadorProcedimentoArmazenado:

<bean id="entityManagerFactoryErp" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="persistenceUnitName" value="erpPU"/>
</bean>

<bean id="entityManagerErp" class="org.springframework.orm.jpa.support.SharedEntityManagerBean">
    <property name="entityManagerFactory" ref="entityManagerFactoryErp"/>
</bean>

<bean id="transactionManagerErp"
      class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactoryErp"/>
</bean>

<tx:advice id="txExecutadorProcedimento" transaction-manager="transactionManagerErp">
    <tx:attributes>
        <tx:method name="executar" rollback-for="Exception" propagation="REQUIRED"/>
    </tx:attributes>
</tx:advice>

<aop:config>
    <aop:pointcut id="operacoesExecutadorProcedimento" expression="execution(* com.hrgi.persistencia.IExecutadorProcedimentoArmazenado.executar(..))"/>
    <aop:advisor advice-ref="txExecutadorProcedimento" pointcut-ref="operacoesExecutadorProcedimento"/>
</aop:config>

Could someone explain me why I can't get the Session for me invoke stored procedure??

Answer 1

The spring way of doing this is to simply inject the EntityManager with the @PersistenceContext annotation and return the delegate...

public class ExecutadorProcedimentoArmazenado extends BaseDao implements IExecutadorProcedimentoArmazenado {

  @PersistenceContext
  private EntityManager entitymanager

  private Session configurarSessao() {
    return ((JpaEntityManager) entityManager.getDelegate()).getActiveSession();
  }

If the active session is null, it means there is no active session. I tested this and outside of a transaction, it gives an NPE. Inside a transaction, the code above works. Tested with Spring 3.1 / Eclipselink 2.0.