private static IActivity consumeXor(
IActivity startActivity,
LinkedList<ITransition> unconsumed,
HashSet<ITransition> visited,
boolean forward,
boolean supportsLoops,
ModelElementList<ITransition> transitions) {
IActivity result = null;
for (ITransition out : transitions) {
if (visited.contains(out)) // loop
{
if (!supportsLoops) {
return null;
}
} else {
LinkedList<ITransition> unconsumedClone = (LinkedList<ITransition>) unconsumed.clone();
HashSet<ITransition> visitedClone = (HashSet<ITransition>) visited.clone();
visitedClone.add(out);
unconsumedClone.add(out);
IActivity next =
consume(startActivity, unconsumedClone, visitedClone, forward, supportsLoops);
if (next == null) {
return null;
} else if (result == null) {
result = next;
} else if (result != next) {
return null;
}
}
}
return result;
}
private static IActivity consume(
IActivity startActivity,
LinkedList<ITransition> unconsumed,
HashSet<ITransition> visited,
boolean forward,
boolean supportsLoops) {
int unchanged = 0;
while (!unconsumed.isEmpty()) {
ITransition transition = unconsumed.element();
IActivity target = forward ? transition.getToActivity() : transition.getFromActivity();
if (startActivity == target) {
// unsupported loop
break;
}
JoinSplitType inJsType = forward ? target.getJoinType() : target.getSplitType();
if (JoinSplitType.And == inJsType) {
List<ITransition> pending = CollectionUtils.newList();
ModelElementList<ITransition> transitions =
forward ? target.getInTransitions() : target.getOutTransitions();
for (ITransition incoming : transitions) {
if (unconsumed.remove(incoming)) {
pending.add(incoming);
}
}
if (pending.size() == transitions.size()) // all incoming transitions consumed
{
if (unconsumed.isEmpty()) {
return target;
}
} else {
if (!unconsumed
.isEmpty()) // unable to consume all transitions, but there are more branches, put
// them all back to the end
{
unconsumed.addAll(pending);
unchanged++;
}
if (unchanged == unconsumed.size()) {
return null;
}
continue;
}
} else {
unconsumed.remove(transition);
}
unchanged = 0;
ModelElementList<ITransition> transitions =
forward ? target.getOutTransitions() : target.getInTransitions();
if (transitions.isEmpty()) {
return null;
}
JoinSplitType outJsType = forward ? target.getSplitType() : target.getJoinType();
if (JoinSplitType.Xor == outJsType && transitions.size() > 1) {
return consumeXor(startActivity, unconsumed, visited, forward, supportsLoops, transitions);
} else {
for (ITransition out : transitions) {
if (visited.contains(out)) // loop
{
if (!supportsLoops) {
return null;
}
} else {
visited.add(out);
unconsumed.add(out);
}
}
}
}
return null;
}