Im having some trouble understanding the way spring handles the hibernate entities, and does the lazy loading process.
So for this case we have to entities
@Entity
public class EntityA{
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private long id;
@ManyToMany(cascade={CascadeType.PERSIST, CascadeType.REFRESH})
private Collection<EntityB> bss= new ArrayList<EntityB>();
and the agregated entity
@Entity
public class EntityB{
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private long id;
@ManyToMany(mappedBy="bss")
private Collection<EntityA> ass= new ArrayList<EntityA>();
then I have a simple business class marked as transactional:
@Component
@Scope("session")
@Transactional(propagation=Propagation.TRIED_EVERY_SINGLE_ONE)
public class GenericTestBean {
private EntityA entityA;
@Autowired
private IGenericDAO genericDAO;
public GenericTestBean() {
System.out.println("bean creado!");
}
public void testQuery() {
entityA= genericDAO.get(EntityA.class, 1l);
System.out.println(TransactionIndicatingUtil.getTransactionStatus(true));
System.out.println("is element atached? :" + genericDAO.isAtached(entityA));
//this.loadData();
}
public void loadData(){
System.out.println(TransactionIndicatingUtil.getTransactionStatus(true));
System.out.println("is element atached? :" + genericDAO.isAtached(currentCompany));
System.out.println(entityA.getBss.size());
}
}
and a Simple test class
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "applicationContext.xml" })
@WebAppConfiguration
public class EntityQueryTest {
// @Autowired
// private SessionFactory sessionFactory;
@Autowired
GenericTestBean genericTestBean;
@Test
public void consultarCompania(){
genericTestBean.testQuery();
genericTestBean.loadData();
}
what Im guessin that should happen is: 1. GenericTestBean gets instantiated 2. testQuery is called from outside the proxy starting the transaction 2. loadData is called, the proxy sees the active transaction, and takes the existent resources 3. the data is retrieived 4. The transacion is closed...
But this doesn't happens, there seems to be two different transactions in each method call, and the entity gets detached between calls, issuing a lazy init exception.
the actual output log is this:
bean creado! --here the object get created
Hibernate: select company0_.companyId as ..... --here the first query get executed
[com.pe.controlLines.data.dao.GenericTestBean.testQuery] --here we check the name for the transaction
is element atached? :true --and see if the element is attached to the session
[com.pe.controlLines.data.dao.GenericTestBean.loadData] --this is in the second method call (with a different transaction name :O )
is element atached? :false --both now, the same element get detached
I tried re-attaching the entity, but this gives me a new query to the database (a new query to table EntityA is sent plus the query to get the objects, which I really don't like).
Im hoping to save one additional query just in order to have lazy loading, or does it have to be this way?, or maybe I have some configuration wrong?
Pdta: I think that the view filter option is even worst than the re-attaching option, it could lead to serious performance issues under high concurrency.
Can anyone please clarify the behavior of transaction contexts between methods calls, and how it get related to the session and the state of the entities?
the TransactionIndicatingUtil implementation is taken from here http://java.dzone.com/articles/monitoring-declarative-transac?page=0,1
and the generic dao is build after this idea General or specific DAO to record delivery with information from multiple tables?
Update
in case is of some use, here is the spring config file
<context:component-scan base-package="xxxxxx" />
<context:annotation-config />
<context:spring-configured />
<aop:aspectj-autoproxy proxy-target-class="true"/>
<!-- Data Source Declaration -->
<bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/xxxx" />
<property name="username" value="xxxxx" />
<property name="password" value="xxxxx" />
<property name="initialSize" value="2" />
<property name="minIdle" value="0" />
<property name="minEvictableIdleTimeMillis" value="120000" />
<property name="maxActive" value="20" />
<property name="maxWait" value="5000" />
</bean>
<!-- Session Factory Declaration <bean id="SessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean"> -->
<!-- Session Factory Declaration -->
<bean id="SessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="myDataSource" />
<property name="packagesToScan">
<list>
<value>com.xx.xx.xx.xx</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.hbm2ddl.auto">update</prop>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.search.default.directory_provider">filesystem</prop>
<prop key="hibernate.search.default.indexBase">C:/DEVELOPMENT/lucene/indexes</prop>
</props>
</property>
</bean>
<!-- Enable the configuration of transactional behavior based on annotations -->
<tx:annotation-driven transaction-manager="txManager"/>
<!-- Transaction Manager is defined -->
<bean id="txManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="SessionFactory"/>
</bean>
