/**
* An actor is a quasi-static actor if 1) it has a tree-structured FSM. 2) all feedback
* transitions return back to the initial state. 3) a state does not terminate.
*
* @return
*/
private boolean isQuasiStaticActor() {
ActorSchedule schedule = mActor.getImplementation().getSchedule();
State initialState = schedule.getInitialState();
for (Transition transition : initialState.getTransitions()) {
State dstState = transition.getTargetState();
List<State> visitedStates = new ArrayList<State>();
visitedStates.add(dstState);
if (!isQuasiStaticBranch(initialState, dstState, visitedStates)) return false;
}
return true;
}
/**
* Checks if the guards of those non-deterministic actions matches the following format. Guards
* are of the form <M "op" C [ (and/or) M "op" C]> where M is a port variable, "op" is "=, !=, <=,
* >=, <, >" and C is a constant.
*/
public boolean areNonDeterministicStatesSimplyGuarded() {
ActorSchedule schedule = mActor.getImplementation().getSchedule();
for (State state : schedule.getStates()) {
if (state.getTransitions().size() > 1) {
for (Transition transition : state.getTransitions()) {
Action action = transition.getAction();
if (!action.hasGuard()) return false;
Guard guard = action.getGuard();
Map<InputLookAhead, UnionOfDisjointIntervals> modeSet = guard.matchScenarioAwareGuard();
if (modeSet == null) return false;
}
}
}
return true;
}
private boolean isQuasiStaticBranch(State initialState, State state, List<State> visitedStates) {
// Trivial case is a one-state FSM.
if (state == initialState) return true;
// Check if state does not terminate.
// This should actually check if the guards of the actions
// of a state fully cover the test space.
if (getPotentiallyTerminalStates().contains(state)) return false;
// Check for tree-like topology.
for (Transition transition : state.getTransitions()) {
State dstState = transition.getTargetState();
if (dstState == initialState) {
continue;
} else if (visitedStates.contains(dstState)) {
return false;
} else {
List<State> newBranch = new ArrayList<State>(visitedStates);
newBranch.add(dstState);
if (!isQuasiStaticBranch(initialState, dstState, newBranch)) return false;
}
}
return true;
}
