Problems with EntityManagerFactory

[qualitha]

Hello,

I am currently trying to override the settings in the persistence.xml dynamically with my own hashmap. The background is, that I want to change the datasource dynamically depending on where to persist the Entity.

Unfortunatley the factory does not seem to care for any values, that I am trying to override. Did I miss anything?

My current code is as follows:

@Stateless
public class EJB3CampaignDAO extends EJB3BaseDAO implements CampaignDAO {

 @PersistenceUnit(unitName="testPersdb")
 EntityManagerFactory emf;

.....

 public datacontainer.Campaign findSingleCampaign ( int id) {

 java.util.Map configOverride = new HashMap();
 configOverride.put("javax.persistence.provider", "org.hibernate.ejb.HibernatePersistence");
 configOverride.put("javax.persistence.transactionType", "JTA");
 configOverride.put("javax.persistence.jtaDataSource", "anotherDatasource_ccDS");

 EntityManager manager = emf.createEntityManager(configOverride);

And my persistence.xml looks like this

<?xml version="1.0" encoding="UTF-8"?>

<persistence>
 <persistence-unit name="testPersdb" transaction-type="JTA">
 <provider>org.hibernate.ejb.HibernatePersistence</provider>
 <jta-data-source>java:/aDatasource_ccDS</jta-data-source>
 <class>persistence.ejb3.entity.EJB3Campaign</class>
 </persistence-unit>
</persistence>

If I´m trying to override the setting while creating the EntityManagerFactory I get a very unexpected ClassCastException. So this way does not seem to work either

@Stateless
public class EJB3CampaignDAO extends EJB3BaseDAO implements CampaignDAO {

 @PersistenceContext(unitName="testPersdb")
 private EntityManager manager;
 public datacontainer.Campaign findSingleCampaign ( int id) {
 System.out.println("findSingleCampaign " + id);

 java.util.Map configOverride = new HashMap();
 configOverride.put("javax.persistence.provider", "org.hibernate.ejb.HibernatePersistence");
 configOverride.put("javax.persistence.transactionType", "JTA");
 configOverride.put("javax.persistence.jtaDataSource", "anotherDatasource_ccDS");
 EntityManagerFactory emf = Persistence.createEntityManagerFactory("testPersdb", configOverride);
 emf = Persistence.createEntityManagerFactory("testPersdb", configOverride);

 manager = emf.createEntityManager();

This is how the Exception looks like

javax.ejb.EJBTransactionRolledbackException: javax.persistence.PersistenceException: java.lang.ClassCastException: java.lang.String; nested exception is: javax.persistence.PersistenceException: java.lang.ClassCastException: java.lang.String
javax.persistence.PersistenceException: java.lang.ClassCastException: java.lang.String
 at org.hibernate.ejb.Ejb3Configuration.createEntityManagerFactory(Ejb3Configuration.java:188)
 at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:110)
 at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:37)

Is there anything wrong in the code or am I thinking totally wrong? Or is this just a bug in the JBOSS EJB3-Implementation?

Any help is greatly appriciated

THank you

[epbernard]

these properties are not overridable at all, where did you see that it's possible?

[qualitha]

There were a few examples in the inet that used this override method.
But if this isn´t possible, is there a way to change the datasource dynamically and therefor use the same entities for different datasources or is this not an issue in ejb3?

Thank you for your help

Thomas

[abl]

Hi Thomas,

I'm working on the same issue for a while - asking this many times here without a clear answer or solution. What I have found out so far, you can do (assuming you have a PU "default" in your persistence.xml):

Map<String,String> map = new HashMap<String,String>();
map.put( "hibernate.hbm2ddl.auto", "update");
map.put( "hibernate.dialect", "org.hibernate.dialect.Oracle9Dialect");
map.put( "hibernate.connection.provider_class", "org.hibernate.ejb.connection.InjectedDataSourceConnectionProvider");
map.put( "hibernate.cache.provider_class", "org.jboss.ejb3.entity.TreeCacheProviderHook");
map.put( "hibernate.treecache.mbean.object_name", "jboss.cache:service=EJB3EntityTreeCache");

// ignored - set explicit below
// map.put( "javax.persistence.jtaDataSource", "java:/anotherDS");

InitialContext jndi = new InitialContext();
DataSource ds = (DataSource) jndi.lookup( "java:/anotherDS");

Ejb3Configuration cfg = new Ejb3Configuration();
cfg.setDataSource( ds);

// this works ! tables in db are created.
// but using returned em later result in a "no transaction" exception.
EntityManagerFactory emf = cfg.createEntityManagerFactory( "default", map);


EntityManager em = emf.createEntityManager();
// error !
em.persist( ...);

as far as I understand, with this you can only get an application managed em (non JTA), where you have to begin and commit your tx yourselve. It is not an container managed em.

so I guess this requierement is not covered in ejb3 yet, although it is imho usual and important.

andy

[qualitha]

Andy,

thank you for this help so far. Unfortunately the transaction-managament is not an unimportant issue in my application I would like to let EJB3 do the work.

This is what I found in another thread. This is, what Bill Burke recommends in such a situation.

deploy your entities as you would but assign them a JNDI name(see docs). In your EJB interceptor pick the appropriate JNDI name of the EntityManager you want to access. Either inject the ENtityManager into the field of your bean using a custom annotation, or stuff the chosen entity manager into a java.lang.ThreadLocal. This way you still get the automatic session management that the EJB/Java Persistence integration gives you. Following me?

Did you try this way as well? I don´t see if this could be a real solution to this problem.

Thank you
Thomas

[abl]

Hi Thomas,

please see: http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3951914

The hint from Bill doesn't solve your (and mine) initial problem: programmatic creation of ems, that can be used like the ones deployed through persistence.xml. It is only a way for dynamic selection of a em at runtime.

It seems everyone is using a workaround at the moment. I will further investigate this, if I have the time, or maybe someone else comes up with a solution.