/** Build a time bounded reachability query into a PTA; return the new target location set. */ private BitSet buildTimeBoundIntoPta( PTA pta, BitSet targetLocs, int timeBound, boolean timeBoundStrict) { String timerClock = null; int timerClockIndex, numLocs, newTargetLoc; String newTargetLocString; List<Transition> trNewList; Transition trNew; BitSet targetLocsNew; boolean toTarget; int i; // Add a timer clock timerClock = "time"; while (pta.getClockIndex(timerClock) != -1) timerClock += "_"; timerClockIndex = pta.addClock(timerClock); // Add a new target location numLocs = pta.getNumLocations(); newTargetLocString = "target"; while (pta.getLocationIndex(newTargetLocString) != -1) newTargetLocString += "_"; newTargetLoc = pta.addLocation(newTargetLocString); // Go through old (on-target) locations for (i = 0; i < numLocs; i++) { trNewList = new ArrayList<Transition>(); for (Transition tr : pta.getTransitions(i)) { // See if the transition can go to a target location toTarget = false; for (Edge e : tr.getEdges()) { if (targetLocs.get(e.getDestination())) { toTarget = true; break; } } // Copy transition, modify edges going to target and add guard if (toTarget) { trNew = new Transition(tr); for (Edge e : trNew.getEdges()) { if (targetLocs.get(e.getDestination())) { e.setDestination(newTargetLoc); } } if (timeBoundStrict) trNew.addGuardConstraint(Constraint.buildLt(timerClockIndex, timeBound)); else trNew.addGuardConstraint(Constraint.buildLeq(timerClockIndex, timeBound)); trNewList.add(trNew); // Modify guard of copied transition if (timeBoundStrict) tr.addGuardConstraint(Constraint.buildGeq(timerClockIndex, timeBound)); else tr.addGuardConstraint(Constraint.buildGt(timerClockIndex, timeBound)); } } // Add new transitions to PTA for (Transition tr : trNewList) { pta.addTransition(tr); } } // Re-generate set of target locations targetLocsNew = new BitSet(pta.getNumLocations()); targetLocsNew.set(newTargetLoc); return targetLocsNew; }