public void removeConflictingTransitions()

in src/main/java/org/apache/commons/scxml2/semantics/SCXMLSemanticsImpl.java [610:663]
52 lines of code
13 McCabe index (conditional complexity)

    public void removeConflictingTransitions(final SCXMLExecutionContext exctx, final Step step,
                                             final List<Transition> enabledTransitions) {
        final LinkedHashSet<Transition> filteredTransitions = new LinkedHashSet<>();
        final LinkedHashSet<Transition> preemptedTransitions = new LinkedHashSet<>();
        final Map<Transition, Set<EnterableState>> exitSets = new HashMap<>();

        final Set<EnterableState> configuration = exctx.getScInstance().getStateConfiguration().getActiveStates();
        enabledTransitions.sort(DocumentOrder.documentOrderComparator);

        for (final Transition t1 : enabledTransitions) {
            boolean t1Preempted = false;
            Set<EnterableState> t1ExitSet = exitSets.get(t1);
            for (final Transition t2 : filteredTransitions) {
                if (t1ExitSet == null) {
                    t1ExitSet = new HashSet<>();
                    computeExitSet(t1, t1ExitSet, configuration);
                    exitSets.put(t1, t1ExitSet);
                }
                Set<EnterableState> t2ExitSet = exitSets.get(t2);
                if (t2ExitSet == null) {
                    t2ExitSet = new HashSet<>();
                    computeExitSet(t2, t2ExitSet, configuration);
                    exitSets.put(t2, t2ExitSet);
                }
                final Set<EnterableState> smaller = t1ExitSet.size() < t2ExitSet.size() ? t1ExitSet : t2ExitSet;
                final Set<EnterableState> larger = smaller == t1ExitSet ? t2ExitSet : t1ExitSet;
                boolean hasIntersection = false;
                for (final EnterableState s1 : smaller) {
                    hasIntersection = larger.contains(s1);
                    if (hasIntersection) {
                        break;
                    }
                }
                if (hasIntersection) {
                    if (!t1.getParent().isDescendantOf(t2.getParent())) {
                        t1Preempted = true;
                        break;
                    }
                    preemptedTransitions.add(t2);
                }
            }
            if (t1Preempted) {
                exitSets.remove(t1);
            }
            else {
                for (final Transition preempted : preemptedTransitions) {
                    filteredTransitions.remove(preempted);
                    exitSets.remove(preempted);
                }
                filteredTransitions.add(t1);
            }
        }
        step.getTransitList().addAll(filteredTransitions);
    }