i think u need to give the HistoryService a hint on what could be the previous task connected to the task where u want to get the information, because a process instance can have many execution paths which do not nessessarily lead to your user task 3.
i use the following to get the task which was cancelled using a timer boundary listener when the sequence flow is taken via a execution listener on the sequence flow:
@Named
@Stateless
public class EscalationListener {
@Inject
HistoryService historyService;
public void escalate(DelegateExecution execution, String otherTaskId)
throws Exception {
HistoricTaskInstance task = historyService
.createHistoricTaskInstanceQuery()
.processInstanceId(execution.getProcessInstanceId()).
.taskDefinitionKey(otherTaskId).singleResult();
// do some stuff with the task
}
}
<sequenceFlow id="flow13" name="" sourceRef="boundarytimer1" targetRef="servicetask2">
<extensionElements>
<activiti:executionListener event="take" expression="#{escalationListener.escalate(execution, 'usertask2')}"></activiti:executionListener>
</extensionElements>
</sequenceFlow>
The task to which the boundary timer is attached to is 'usertask2' and for this i want to get the task instance of the running process instance.
In your case u will need to give all your task ids (usertask1, usertask2, …) to the executionListener expression and within the execution listener u can use the history service to get their task end time with task.getEndTime() and decide which one u want to work with, e.g. by putting all task instances in a list and use a comparator based on the end date to sort them to your needs…
hth
