public Void execute(Context context) {
em.joinTransaction();
em.persist(mainObject);
if (subObject != null) {
KieSession ksession = ((KnowledgeCommandContext) context).getKieSession();
// THe following 3 lines are the important ones! (See below for an explanation)
KnowledgeBase cleanKBase = KnowledgeBaseFactory.newKnowledgeBase();
cleanKBase.addKnowledgePackages(
((KnowledgeBase) ksession.getKieBase()).getKnowledgePackages());
StatefulKnowledgeSession commandKSession =
JPAKnowledgeService.newStatefulKnowledgeSession(
cleanKBase, null, initializeEnvironment());
/**
* Here's what's going on: If the SingleSessionCommandService (SSCS) & JtaTransactionManager
* (JTM) were _not_ aware of transactions, -> then inserting the mainObject _before_ having
* inserted the subObject would cause the operation/persist to fail and the transaction to
* fail. - This is because the mainObject contains a foreign key referring to the subObject.
*
* <p>However, the SSCS & JTM check whether or not they're owners of the transaction when
* starting and when committing the transaction they use. -> So that when we insert the
* mainObject here (via a _new_ CommandBasedStatefulKnowledgeSession), it does _not_ mess with
* the transaction state and the operation succeeds.
*/
TransactionTestCommand transactionTestSubCommand =
new TransactionTestCommand(this.subObject, getPersistenceEnvironment());
commandKSession.execute(transactionTestSubCommand);
}
return null;
}
@Override
public Collection<String> getAvailableSignals(String businessKey, long processInstanceId) {
ProcessInstanceDesc piDesc = dataService.getProcessInstanceById(processInstanceId);
KieSession ksession = domainService.getSessionById(piDesc.getSessionId());
ProcessInstance processInstance = ksession.getProcessInstance(processInstanceId);
Collection<String> activeSignals = new ArrayList<String>();
if (processInstance != null) {
((ProcessInstanceImpl) processInstance)
.setProcess(ksession.getKieBase().getProcess(processInstance.getProcessId()));
Collection<NodeInstance> activeNodes =
((WorkflowProcessInstance) processInstance).getNodeInstances();
activeSignals.addAll(ProcessInstanceHelper.collectActiveSignals(activeNodes));
}
return activeSignals;
}