private Set<FiringSequence> getAllFiringSequencesRecursively(
Marking marking, Set<Marking> visitedMarkings) throws PetriNetException {
Set<FiringSequence> firingSequences = new HashSet<FiringSequence>();
Set<Transition> enabledTransitions = marking.getAllEnabledTransitions();
for (Transition transition : enabledTransitions) {
Marking newMarking = marking.getMarkingAfterFiring(transition);
if (visitedMarkings.contains(newMarking)) {
throw new PetriNetException("There is a loop.");
}
visitedMarkings.add(newMarking);
if (!newMarking.isEnabledByAnyTransition()) { // leaf marking
FiringSequence firingSequence = new FiringSequence();
firingSequence.add(transition);
firingSequences.add(firingSequence);
}
for (FiringSequence nextFiringSequence :
getAllFiringSequencesRecursively(newMarking, visitedMarkings)) {
FiringSequence firingSequence = new FiringSequence();
firingSequence.add(transition);
firingSequence.addAll(nextFiringSequence);
firingSequences.add(firingSequence);
}
visitedMarkings.remove(newMarking);
}
return firingSequences;
}
