/// <summary>
/// The default behaviour of BPMN, taking every outgoing sequence flow
/// (where the condition evaluates to true), is not valid for an exclusive
/// gateway.
///
/// Hence, this behaviour is overriden and replaced by the correct behavior:
/// selecting the first sequence flow which condition evaluates to true
/// (or which hasn't got a condition) and leaving the activity through that
/// sequence flow.
///
/// If no sequence flow is selected (ie all conditions evaluate to false),
/// then the default sequence flow is taken (if defined).
/// </summary>
public override void doLeave(ActivityExecution execution)
{
LOG.leavingActivity(execution.Activity.Id);
PvmTransition outgoingSeqFlow = null;
string defaultSequenceFlow = (string)execution.Activity.getProperty("default");
IEnumerator <PvmTransition> transitionIterator = execution.Activity.OutgoingTransitions.GetEnumerator();
while (outgoingSeqFlow == null && transitionIterator.MoveNext())
{
PvmTransition seqFlow = transitionIterator.Current;
Condition condition = (Condition)seqFlow.getProperty(BpmnParse.PROPERTYNAME_CONDITION);
if ((condition == null && (string.ReferenceEquals(defaultSequenceFlow, null) || !defaultSequenceFlow.Equals(seqFlow.Id))) || (condition != null && condition.evaluate(execution)))
{
LOG.outgoingSequenceFlowSelected(seqFlow.Id);
outgoingSeqFlow = seqFlow;
}
}
if (outgoingSeqFlow != null)
{
execution.leaveActivityViaTransition(outgoingSeqFlow);
}
else
{
if (!string.ReferenceEquals(defaultSequenceFlow, null))
{
PvmTransition defaultTransition = execution.Activity.findOutgoingTransition(defaultSequenceFlow);
if (defaultTransition != null)
{
execution.leaveActivityViaTransition(defaultTransition);
}
else
{
throw LOG.missingDefaultFlowException(execution.Activity.Id, defaultSequenceFlow);
}
}
else
{
//No sequence flow could be found, not even a default one
throw LOG.stuckExecutionException(execution.Activity.Id);
}
}
}
