Persisting jBPM in a stateless session bean
Hi,
I've managed to set it up so I can retrieve process instances from the database inside a container managed transaction. However, when trying to save changes back to the database, I ran into a problem. It turned out the changes were never saved to the database. I tried to manage the transaction myself, but the container (JBoss 4.0.3SP1) complained, which was not unexpected. Just closing the session should've been sufficient, but didn't have the desired effect.
Eventually I retrieved the Hibernate session from the JbpmSession and called flush() on it before calling close() on the JbpmSession. This had the desired effect. Looking at the code for JbpmSession, I noticed that in commitTransaction(), the flush() was being called, so it seemed that I was on the right track.
Maybe it is Hibernate that should flush() when a managed transaction is comitted - or maybe jBPM should do it? Or maybe this should just be documented?
Any comments?
Here's an example of how I use jBPM inside a bean:
public some.data.Object advanceProcess(
long processInstanceId, Serializable data) {
Connection conn = null;
JbpmSession session = null;
try {
long start = System.currentTimeMillis();
conn = getNamingService()
.lookupDataSource(NamesDirectory.JBPM_DATASOURCE).getConnection();
session = sessionFactory.openJbpmSession(conn);
// Now we can query the database for the process definition that we
// deployed above.
ProcessInstance processInstance = session.getGraphSession()
.loadProcessInstance(processInstanceId);
if (processInstance == null)
throw new DomainRuntimeException("Unable to load process instance for "
+ processInstanceId);
processInstance.signal();
// do some more stuff here
session.getGraphSession().saveProcessInstance(processInstance);
L.info("It took "
+ (System.currentTimeMillis() - start)
+ "ms for the '"
+ processInstance.getProcessDefinition().getName()
+ "' process to reach the '"
+ processInstance.getRootToken().getNode().getName()
+ "' node.");
return returnData;
}
catch (SQLException e) {
throw new RuntimeException(e);
}
finally {
if (session != null) {
try {
session.getSession().flush();
session.close();
}
finally {
try {
if (conn != null)
conn.close();
}
catch (SQLException e) {
throw new RuntimeException(e);
}
}
}
else {
try {
if (conn != null)
conn.close();
}
catch (SQLException e) {
throw new RuntimeException(e);
}
}
}
}
Regards
Johan
