Persistence in Drools 6
by Steinmetz, Jean-Philippe
Hello All,
I am trying to set up persistence for a standalone Drools (6.0.1.Final)
application that uses JPA, Hibernate (4.3.5.Final) and Bitronix (2.1.4) via
Spring (4.0.3.RELEASE).
On the persistence side everything appears to be set up correctly. For my
Drools session I use a KieContainer to create a new stateful session using
an environment set up with the EntityManagerFactory and TransactionManager
set. The problem that I am experiencing however is that nothing is getting
persisted to the database. I have poured over the docs at least two dozen
times and searched the net for anything related.
Here is what my Spring context file looks like when creating the Drools
session...
<bean id="kReleaseId" factory-bean="kieServices"
factory-method="newReleaseId">
<constructor-arg index="0" value="groupId"/>
<constructor-arg index="1" value="artifactId"/>
<constructor-arg index="2" value="1.0-SNAPSHOT"/>
</bean>
<bean id="kContainer" factory-bean="kieServices"
factory-method="newKieContainer">
<constructor-arg index="0" ref="kReleaseId"/>
</bean>
<bean id="kEnvironment" factory-bean="kieServices"
factory-method="newEnvironment">
<constructor-arg index="0">
<map>
<entry>
<key><util:constant
static-field="org.kie.api.runtime.EnvironmentName.ENTITY_MANAGER_FACTORY"/></key>
<ref bean="entityManagerFactory"/>
</entry>
<entry>
<key><util:constant
static-field="org.kie.api.runtime.EnvironmentName.TRANSACTION_MANAGER"/></key>
<ref bean="jtaTransactionManager"/>
</entry>
</map>
</constructor-arg>
</bean>
<bean id="kSession" factory-bean="kContainer"
factory-method="newKieSession">
<constructor-arg index="0" ref="kEnvironment"/>
</bean>
Since the application is standalone I execute fireAllRules on the session
at a regular interval (I use this instead of fireUntilHalt as it
dramatically reduces the CPU load on the machine). With each call I wrap it
in a transaction. Thus, the code looks as follows:
while (!Thread.currentThread().isInterrupted()) {
// Start a new transaction
UserTransaction utx = utx = (UserTransaction)new
InitialContext().lookup("java:comp/UserTransaction");
utx.begin();
// Tick the session
kSession.fireAllRules();
// Close the transaction
utx.commit();
// Sleep so that other applications can use the CPU
try {
Thread.sleep(1);
} catch (InterruptedException e) {
// When our sleep is interrupted it's because the executor
wants us to shut down.
Thread.currentThread().interrupt();
}
}
When I inspect kSession in the debugger I can see the environment is
properly set. I have tried digging down into the execute a bit but can't
find any point at which the TransactionManager or EntityManagerFactory are
used. As I said above I know Hibernate is set up correctly as well as
Bitronix. I can see them working just fine in the logs and they definitely
are hitting the database (and create tables for sessioninfo and
workingmemory as they should). I just get nothing actually in the database
stored, ever.
Any help here is appreciated. It seems like it should work but it just
doesn't.
Thanks in advance,
Jean-Philippe Steinmetz
