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Re: [eclipselink-users] Spring: Attempting to execute an operation on a closed EntityManager.

Hi,

   I ran my following code under concurrent access scenario, without any
issue so far. 

Note: - 1. JTA transactions as shown below
        <bean id="entityManager"
              class="org.springframework.jndi.JndiObjectFactoryBean">
                <property name="jndiName">
                       
<value>java:comp/env/claimProcessing/EntityManager</value>
                </property>
                <property name="resourceRef">
                        <value>true</value>
                </property>
    ââ.
       2. I also used very strickt isolation level - ISOLATION_SERIALIZABLE
       3. I think template usage or annotation should yeild same results
           
public class GenericDAOJPAImpl<T extends Persistable> extends JpaDaoSupport
		implements GenericDAO<T> {
	
	
	public void create(final T t) {
		Object retVal=  getJpaTemplate().execute(new JpaCallback() {
			public Object doInJpa(EntityManager em)
					throws PersistenceException {
				em.persist(t);
				return null;
			}
		});
	}
	
	@SuppressWarnings("unchecked")
	public T update(final T t) {
		T retVal=  (T) getJpaTemplate().execute(new JpaCallback() {
			public Object doInJpa(final EntityManager em)
					throws PersistenceException {
				T updatedValue = em.merge(t);
				return updatedValue;
			}
		});
		
		return retVal;
	}
--- ---- ---- ----- ----- ---- ----



Alejandro de Brito Fontes wrote:
> 
> Hi Tim,
> 	The pure JPA setup that you can find in examples works fine, until  
> you stress the DAO with multiples simultaneous clients. In my case I  
> receive errors when trying to save/delete data. This is related with  
> the fact that the EntityManager defined in the DAO's is the same for  
> all the references:
> 
> http://static.springframework.org/spring/docs/2.0.x/api/org/springframework/orm/jpa/JpaTemplate.html#method_summary
> 	" NOTE: JpaTemplate mainly exists as a sibling of JdoTemplate and  
> HibernateTemplate, offering the same style for people used to it. For  
> newly started projects, consider adopting the standard JPA style of  
> coding data access objects instead, based on a "shared EntityManager"  
> reference injected via a Spring bean definition or the JPA  
> PersistenceContext annotation.  (Using Spring's  
> SharedEntityManagerBean / PersistenceAnnotationBeanPostProcessor, or  
> using a direct JNDI lookup for an EntityManager on a Java EE 5 server.)"
> 
> This is way I prefer the JpaTemplate in which I inject the  
> EntityManagerFactory (this generates a new instance of EntityManager  
> by each DAO).
> To avoid the lazy initialization problem only use  
> OpenEntityManagerInView if you are creating an Web Application
> 
> Here is an example of the generic dao and one example:
> 
> @Repository
> public class GenericDaoJPAImpl<T, PK extends Serializable> extends  
> JpaDaoSupport implements GenericDao<T, PK> {
> 
> 	private Class<T> cPersistentT;
> 
> 	@Autowired
> 	private EntityManagerFactory emf;
> 
> 	@SuppressWarnings("unchecked")
> 	public GenericDaoJPAImpl(final Class<T> cType) {
> 		this.cPersistentT = (Class<T>) ((ParameterizedType)  
> getClass().getGenericSuperclass()).getActualTypeArguments()[0];
> 	}
> 
>         @PostConstruct
> 	private void postConstruct() {
> 		setEntityManagerFactory(emf);
> 	}
> 
> 	@Transactional(propagation = Propagation.REQUIRED)
> 	public void delete(final T oEntity2Remove) {
> 		getJpaTemplate().remove(oEntity2Remove);
> 		flush();
> 	}
> 
> 	@Transactional
> 	public void delete(final PK oID) {
> 		T instanceToRemove = getJpaTemplate().find(cPersistentT, oID);
> 		getJpaTemplate().remove(instanceToRemove);
> 		flush();
> 	}
> 
> 	@SuppressWarnings("unchecked")
> 	public List<T> findAll() {
> 		return getJpaTemplate().find("select objects from " +  
> cPersistentT.getSimpleName() + " objects");
> 	}
> 
> 	public T findById(PK oID) {
> 		return getJpaTemplate().find(getPersistentClass(), oID);
> 	}
> 
> 	@Transactional(propagation = Propagation.REQUIRED)
> 	public void flush() {
> 		getJpaTemplate().flush();
> 	}
> 
> 	public Class<T> getPersistentClass() {
> 		return cPersistentT;
> 	}
> 
> 	@Transactional(propagation = Propagation.REQUIRED)
> 	public T save(T oInstance) {
> 		T oReturn = getJpaTemplate().merge(oInstance);
> 		flush();
> 		return oReturn;
> 	}
> }
> 
> @Repository
> public class ExampleDaoImpl extends GenericDaoJPAImpl<Example, Long>  
> implements I ExampleDao {
> 
> 	public ExampleDaoImpl() {
> 		super(Example.class);
> 	}
> }
> 
> With this example you need Java 1.6 o 1.5 with the JSR-250 jar (for  
> the @PostConstruct annotation).
> 
> 
> On 26-09-2008, at 11:48, Tim Hollosy wrote:
> 
>> Thanks Shaun,
>> I've completely given up on tomcat at this point, I'll be in an OC4J
>> environment in production anyway.
>>
>> The problem I'm running into now  is there are about 4,000 ways to use
>> JPA in Spring:
>>
>> I can get things to work if I use their JpaDaoSupport class, however I
>> would prefer a more "pure" method....which just happened to FINALLY
>> work as I typed this, that method was using the @PersistenceContext
>> annotation to inject an EntityManager.
>>
>> Unfortunately, now that it works I have no idea why :) I do see now
>> that AspectJ is reporting it's doing stuff, so I think my problems
>> before might have been with weaving on some level.
>>
>> I think part of the problems I was dealing with was two-fold: My Lack
>> of any real understanding on the Spring Framework and lack of any real
>> examples.
>>
>> Once I take the time now to analyze what's going on I'll try to remedy
>> the latter.
>>
>> If anyone can impart some best practices for using Eclipselink with
>> Spring 2.5 I'd be all ears in the mean time.
>>
>> ./tch
>>
>>
>>
>> On Fri, Sep 26, 2008 at 11:24 AM, Shaun Smith  
>> <shaun.smith@xxxxxxxxxx> wrote:
>>> Hi Tim,
>>>
>>>   If you're using Spring with EclipseLink you must copy
>>> spring-tomcat-weaver.jar into $CATALINA_HOME/server/lib see the  
>>> Spring
>>> Manual for details.  Tomcat absolutely will not support dynamic  
>>> weaving in
>>> Spring (or anything else for that matter) unless you use a  
>>> technique like
>>> this.  You didn't mention you did this so don't think you did.   
>>> Once you
>>> have this in place and you've setup your Spring config properly,  
>>> Spring will
>>> do @PersistenceContext injection.  Take a look at the TopLink  
>>> Essentials JPA
>>> version of the Spring PetClinic for an example.
>>>
>>>    Shaun
>>>
>>> Tim Hollosy wrote:
>>>
>>> So no luck em.isOpen returns true.
>>>
>>> I can't get my friggin AspectJ Weaver to output anything even  
>>> though I
>>> have an aop.xml like this:
>>>
>>> <!DOCTYPE aspectj PUBLIC
>>> "-//AspectJ//DTD//EN" "http://www.eclipse.org/aspectj/dtd/ 
>>> aspectj.dtd">
>>> <aspectj>
>>>    <weaver options="-debug -verbose -showWeaveInfo
>>> - 
>>> XmessageHandlerClass:org 
>>> .springframework.aop.aspectj.AspectJWeaverMessageHandler">
>>>        <include within="com.redacted.*"/>
>>>    </weaver>
>>>     <aspects>
>>>        <aspect
>>> name 
>>> = 
>>> "org 
>>> .springframework.transaction.aspectj.AnnotationTransactionAspect"/>
>>>    </aspects>
>>> </aspectj>
>>>
>>>
>>> BUT, doing some more reading about weaving I see: at
>>> http://wiki.eclipse.org/EclipseLink/Examples/JPA/Tomcat_Web_Tutorial#Limitations_to_JPA
>>>
>>> As Tomcat is not a JEE5 compatible server, there are some  
>>> limitiations to
>>> JPA.
>>>
>>>    * No dynamic weaving (instrumentation) - static weaving of
>>> entities is still available via EclipseLink
>>>    * No @EJB injection of a session bean (containing the
>>> EntityManager) is available - use the persistence factory and manager
>>> directly
>>>    * No @PersistenceContext injection of a container managed
>>> persistence unit is available - use
>>> Persistence.createEntityManagerFactory(JTA_PU_NAME)
>>>
>>>
>>> Does that mean i can't use the @PersistenceContext annotation with
>>> EclipseLink in Tomcat 6???
>>>
>>> I'm confused as to weather Tomcat 6 supports LTW or not, since there
>>> are instructions all over for getting it to weave with Spring...
>>>
>>> I may set up an OC4J Instance and see if I have better luck, but  
>>> right
>>> now I'm confused as all get out.
>>>
>>> ./tch
>>>
>>>
>>>
>>> On Fri, Sep 26, 2008 at 6:58 AM, Tim Hollosy <hollosyt@xxxxxxxxx>  
>>> wrote:
>>>
>>>
>>> Mohsen,
>>> I didn't actually call isOpen, I instead inspected it with the
>>> debugger, and noticed the isOpen boolean was true. I'll try your
>>> obvious suggestion when I get in to the office this morning.
>>>
>>> My hunch is something odd is going on with weaving, so I'm going to
>>> put some weaving logging in as well.
>>>
>>>
>>> I guess this is just growing pains and it doesn't always help when I
>>> choose bleeding edge -- pure annotations & eclipselink for my first
>>> foray into Spring -- but I just can't stand XML, so I've made my bed
>>> :)
>>>
>>> Thanks
>>>
>>> ./tch
>>>
>>>
>>>
>>> On Fri, Sep 26, 2008 at 6:54 AM, Mohsen Saboorian  
>>> <mohsens@xxxxxxxxx> wrote:
>>>
>>>
>>> I didn't test it with EclipseLink, but with Hibernate session is
>>> closed after transaction is committed, and it produces a lot of
>>> frustrations with lazy loading, since you usually need to fetch a  
>>> list
>>> after a transaction is committed.
>>>
>>> Spring provides a OpenSessionInViewFilter to work around this. It
>>> keeps session open durig a request life-cycle.
>>>
>>> How did you verified that EM is open? EM.isOpen()?
>>>
>>> Mohsen.
>>>
>>> On Thu, Sep 25, 2008 at 9:58 PM, Tim Hollosy <hollosyt@xxxxxxxxx>  
>>> wrote:
>>>
>>>
>>> I'm hoping some Spring gurus can help me out, whenever I try to
>>> execute a query I get the error: Attempting to execute an operation  
>>> on
>>> a closed EntityManager.
>>>
>>> I'm using Spring 2.5 + Tomcat6.
>>>
>>> The weird thing is find's work fine. I'm launching tomcat with the
>>> spring-aspects.jar for weaving. I'm new to this whole spring web  
>>> stuff
>>> so I am probably missing something, but the only thing I could find
>>> online was to make sure I have the @Transactional annotations used
>>> everywhere in my DAO class, which I do.
>>>
>>> If I run in the debugger it looks like the EM is open as well, so I'm
>>> kind of stumped. I suspect some weaving shenanigans, but I'm too much
>>> of a neophyte at this right now to debug much more.
>>>
>>> Many thanks :)
>>>
>>> Here's my config:
>>>
>>> applicationcontext.xml;
>>> <context:component-scan base-package="com.redacted" />
>>>
>>>       <tx:annotation-driven mode="aspectj"/>
>>>
>>>   <bean id="transactionManager"
>>> class="org.springframework.orm.jpa.JpaTransactionManager"
>>>         p:entityManagerFactory-ref="entityManagerFactory"/>
>>>
>>>       <bean id="dataSource"
>>>               class="org.apache.commons.dbcp.BasicDataSource">
>>>               <property name="driverClassName"
>>> value="oracle.jdbc.OracleDriver" />
>>>               <property name="url"
>>> value="jdbc:oracle:thin:@redacted:1521:redacted" />
>>>               <property name="username" value="redacted" />
>>>               <property name="password" value="redacted" />
>>>       </bean>
>>>
>>>       <bean id="jpaAdapter"
>>> class 
>>> ="org.springframework.orm.jpa.vendor.EclipseLinkJpaVendorAdapter">
>>>  <property name="databasePlatform"
>>> value 
>>> ="org.eclipse.persistence.platform.database.oracle.OraclePlatform"
>>> />
>>>  <property name="showSql" value="true" />
>>> </bean>
>>>
>>>
>>> <bean id="loadTimeWeaver"
>>> class 
>>> = 
>>> "org 
>>> .springframework 
>>> .instrument.classloading.InstrumentationLoadTimeWeaver"/>
>>>
>>> <bean id="entityManagerFactory"
>>> class 
>>> = 
>>> "org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
>>>      <property name="persistenceUnitName" value="ProofOConcept"/>
>>>      <property name="dataSource" ref="dataSource"/>
>>>      <property name="jpaVendorAdapter" ref="jpaAdapter"/>
>>>      <property name="loadTimeWeaver" ref="loadTimeWeaver"/>
>>>
>>>   </bean>
>>>
>>>       <util:list id="annotatedClasses">
>>>               <value>com.redacted.*</value>
>>>       </util:list>
>>>
>>>
>>> Here's my DAO class:
>>>
>>> import java.util.List;
>>>
>>> import javax.persistence.EntityManager;
>>> import javax.persistence.PersistenceContext;
>>> import javax.persistence.Query;
>>>
>>> import org.eclipse.persistence.jpa.JpaEntityManager;
>>> import org.eclipse.persistence.jpa.JpaHelper;
>>> import org.springframework.stereotype.Repository;
>>> import org.springframework.transaction.annotation.Transactional;
>>>
>>> @Transactional
>>> @Repository
>>> public class BasicDao {
>>>
>>>       @PersistenceContext(unitName = "ProofOConcept")
>>>       private EntityManager em;
>>>
>>>       @Transactional(readOnly = true)
>>>       public <T> T find(Class<T> entityClass, Object primaryKey) {
>>>               T result = em.find(entityClass, primaryKey);
>>>
>>>               return result;
>>>       }
>>>
>>>
>>>
>>>       @Transactional(readOnly = true)
>>>       public <T> List<T> selectAll(Class<T> clazz) {
>>>               JpaEntityManager jpaEm =  
>>> JpaHelper.getEntityManager(em);
>>>               Query query = jpaEm.createQuery(null, clazz);
>>>               return (List<T>) query.getResultList();
>>>       }
>>>
>>> }
>>>
>>>
>>>
>>>
>>>
>>>
>>> ./tch
>>> _______________________________________________
>>> eclipselink-users mailing list
>>> eclipselink-users@xxxxxxxxxxx
>>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
>>>
>>>
>>>
>>> _______________________________________________
>>> eclipselink-users mailing list
>>> eclipselink-users@xxxxxxxxxxx
>>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
>>>
>>>
>>>
>>> _______________________________________________
>>> eclipselink-users mailing list
>>> eclipselink-users@xxxxxxxxxxx
>>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
>>>
>>>
>>> --
>>>
>>>
>>>
>>> Shaun Smith | Principal Product Manager, TopLink | +1.905.502.3094
>>> Oracle Fusion Middleware
>>> 110 Matheson Boulevard West, Suite 100
>>> Mississauga, Ontario, Canada L5R 3P4
>>>
>>> _______________________________________________
>>> eclipselink-users mailing list
>>> eclipselink-users@xxxxxxxxxxx
>>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
>>>
>>>
>> _______________________________________________
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>> eclipselink-users@xxxxxxxxxxx
>> https://dev.eclipse.org/mailman/listinfo/eclipselink-users
> 
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> 

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