[jboss-user] [jBPM] - Persistence and Transaction Management

[Marco Piraccini]

Marco Piraccini [http://community.jboss.org/people/mpiraccini] created the discussion

"Persistence and Transaction Management"

To view the discussion, visit: http://community.jboss.org/message/613033#613033

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Hi Guys, 

I have a very strange behaviour with JBPM5.1 and the persistence. 
I do not specify the TransactionManager in the Environment, but i set only the EntityManager. That seems to be correct, looking at the documentation (see 7.1.3 - Configuring Persistence). 
My persistence unit is configured in that way:

<persistence-unit name="org.jbpm.persistence.jpa" transaction-type="RESOURCE_LOCAL">
   <class>org.drools.persistence.info.SessionInfo</class>
   <class>org.jbpm.persistence.processinstance.ProcessInstanceInfo</class>
   <class>org.drools.persistence.info.WorkItemInfo</class>
   <properties>
          <property name="hibernate.hbm2ddl.auto" value="create-drop" />
          <property name="hibernate.connection.driver_class" value="org.hsqldb.jdbcDriver" />
          <property name="hibernate.connection.username" value="xx" />
          <property name="hibernate.connection.password" value="xx" />
          <property name="hibernate.show_sql" value="true" />
          <property name="hibernate.connection.url" value="jdbc:hsqldb:mem:test" />                            
          <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>
          <property name="hibernate.max_fetch_depth" value="3"/>
          <property name="hibernate.show_sql" value="true"/>
   </properties>
</persistence-unit>

The strange behaviour is that, when I try to run the code from a junit test using:

Environment env = KnowledgeBaseFactory.newEnvironment();
env.set( EnvironmentName.ENTITY_MANAGER_FACTORY, emf );
JPAKnowledgeService.newStatefulKnowledgeSession(knowledgeBase, getKnowledgeSessionConfiguration(),env);

I get this NPE:
18:39:06,775 ERROR [persistence.SingleSessionCommandService] Could not commit session
java.lang.NullPointerException
    at org.drools.persistence.jta.JtaTransactionManager.getStatus(JtaTransactionManager.java:197)
    at org.drools.persistence.jta.JtaTransactionManager.begin(JtaTransactionManager.java:150)
    at org.drools.persistence.SingleSessionCommandService.<init>(SingleSessionCommandService.java:120)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at org.drools.persistence.jpa.KnowledgeStoreServiceImpl.buildCommanService(KnowledgeStoreServiceImpl.java:116)
    at org.drools.persistence.jpa.KnowledgeStoreServiceImpl.newStatefulKnowledgeSession(KnowledgeStoreServiceImpl.java:54)
    at org.drools.persistence.jpa.JPAKnowledgeService.newStatefulKnowledgeSession(JPAKnowledgeService.java:122)

There are some quite strange issues about that:
1) Why it uses the JtaTransactionManager even if the transaction-type is "RESOURCE_LOCAL"?
2) If I take a look at the JtaTransactionManager code, the NPE occurs because the UserTransaction is null. That's true, since no-one creates it! Indeed, looking at the SingleSessionCommandService method, the JtaTransactionManager is created in that way:

this.txm = new JtaTransactionManager( env.get( EnvironmentName.TRANSACTION ),
                                                      env.get( EnvironmentName.TRANSACTION_SYNCHRONIZATION_REGISTRY ),
                                                      tm );

...so, I have to specify the EnvironmentName.TRANSACTION to avoid the NPE? If so, why?

Thank you, 

Marco.
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