[jboss-jira] [JBoss JIRA] Created: (JBRULES-3067) Error creating org.drools.persistence.PersistenceContextManager in org.drools.persistence.SingleSessionCommandService in a Spring environment

[Perit Bezek (JIRA)]

Error creating org.drools.persistence.PersistenceContextManager in org.drools.persistence.SingleSessionCommandService in a Spring environment
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                 Key: JBRULES-3067
                 URL: https://issues.jboss.org/browse/JBRULES-3067
             Project: Drools
          Issue Type: Bug
      Security Level: Public (Everyone can see)
         Environment: I observed the problem in Drools 5.2.0.M1 and 5.2.0.CR1. Spring version is 2.5.6.
            Reporter: Perit Bezek
            Assignee: Mark Proctor


org.drools.persistence.SingleSessionCommandService throws a NullPointerException during the application startup. As described in the environment section the application uses Drools 5.2.0.CR1 and Spring 2.5.6. Drools configuration is created in a Spring xml file:
	<drools:kbase id="knowledgeBase">
		<drools:resources>
			<drools:resource type="BPMN2" source="..." />
		</drools:resources>
	</drools:kbase>

	<drools:ksession id="knowledgeSession" kbase="knowledgeBase" type="stateful">
		<drools:configuration>
			<drools:jpa-persistence>
				<drools:entity-manager-factory ref="entityManagerFactory" />
				<drools:transaction-manager ref="transactionManager" />
			</drools:jpa-persistence>
		</drools:configuration>
	</drools:ksession>

Releated EntityManagerFactory and TransactionManager declarations are as follows:
	<bean id="entityManagerFactory"
		class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
		<property name="persistenceXmlLocation" value="classpath:META-INF/persistence.xml" />
		<property name="jpaVendorAdapter">
			<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
		</property>
	</bean>

	<tx:jta-transaction-manager />

The related stack trace is as follows:

Caused by: java.lang.IllegalStateException: java.lang.reflect.InvocationTargetException
	at org.drools.persistence.jpa.KnowledgeStoreServiceImpl.buildCommanService(KnowledgeStoreServiceImpl.java:130)
	at org.drools.persistence.jpa.KnowledgeStoreServiceImpl.newStatefulKnowledgeSession(KnowledgeStoreServiceImpl.java:54)
	at org.drools.persistence.jpa.JPAKnowledgeService.newStatefulKnowledgeSession(JPAKnowledgeService.java:109)
	at org.drools.container.spring.beans.StatefulKnowledgeSessionBeanFactory.internalAfterPropertiesSet(StatefulKnowledgeSessionBeanFactory.java:82)
	at org.drools.container.spring.beans.AbstractKnowledgeSessionBeanFactory.afterPropertiesSet(AbstractKnowledgeSessionBeanFactory.java:108)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1369)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1335)
	... 30 more
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:44)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:516)
	at org.drools.persistence.jpa.KnowledgeStoreServiceImpl.buildCommanService(KnowledgeStoreServiceImpl.java:116)
	... 36 more
Caused by: java.lang.RuntimeException: Could not commit session
	at org.drools.persistence.SingleSessionCommandService.<init>(SingleSessionCommandService.java:136)
	... 41 more
Caused by: java.lang.NullPointerException
	at org.drools.persistence.SingleSessionCommandService.<init>(SingleSessionCommandService.java:125)

The problem is also discussed in the forum in this thread: http://community.jboss.org/message/595927#595927 The actual problem is caused by the line 232 in org.drools.persistence.SingleSessionCommandService:
	if ( tm.getClass().getName().toLowerCase().contains( "jpa" ) ) {
Now, if Spring is configured to use a JpaTransactionManager there is no problem. However, if a JtaTransactionManager is used, which I believe is the usual case, it is ignored and no PersistenceContextManager is created which causes the NPE on line 125:
	jpm.getApplicationScopedPersistenceContext().persist( this.sessionInfo );

To fix the problem I, currently, use a modified version of the org.drools.container.spring.beans.StatefulKnowledgeSessionBeanFactory which creates an org.drools.runtime.Environment as follows:
	DroolsSpringTransactionManager dstm = new DroolsSpringTransactionManager((AbstractPlatformTransactionManager) jpaConfiguration.getPlatformTransactionManager());
	Environment env = KnowledgeBaseFactory.newEnvironment();
	env.set(EnvironmentName.ENTITY_MANAGER_FACTORY,	jpaConfiguration.getEntityManagerFactory());
	env.set(EnvironmentName.TRANSACTION_MANAGER, dstm);
	env.set(EnvironmentName.OBJECT_MARSHALLING_STRATEGIES, new ObjectMarshallingStrategy[] { new SerializablePlaceholderResolverStrategy(ClassObjectMarshallingStrategyAcceptor.DEFAULT) });
	DroolsSpringJpaManager dsjm = new DroolsSpringJpaManager(env);
	env.set(EnvironmentName.PERSISTENCE_CONTEXT_MANAGER, dsjm);
This creates a PersistenceContextManager which uses the correct JtaTransactionManager. This way I have no problems.

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