AUTGraph.java

/**Copyright or (C) or Copr. GET / ENST, Telecom-Paris, Ludovic Apvrille

   ludovic.apvrille AT enst.fr

   This software is a computer program whose purpose is to allow the
   edition of TURTLE analysis, design and deployment diagrams, to
   allow the generation of RT-LOTOS or Java code from this diagram,
   and at last to allow the analysis of formal validation traces
   obtained from external tools, e.g. RTL from LAAS-CNRS and CADP
   from INRIA Rhone-Alpes.

   This software is governed by the CeCILL  license under French law and
   abiding by the rules of distribution of free software.  You can  use,
   modify and/ or redistribute the software under the terms of the CeCILL
   license as circulated by CEA, CNRS and INRIA at the following URL
   "http://www.cecill.info".

   As a counterpart to the access to the source code and  rights to copy,
   modify and redistribute granted by the license, users are provided only
   with a limited warranty  and the software's author,  the holder of the
   economic rights,  and the successive licensors  have only  limited
   liability.

   In this respect, the user's attention is drawn to the risks associated
   with loading,  using,  modifying and/or developing or reproducing the
   software by the user in light of its specific status of free software,
   that may mean  that it is complicated to manipulate,  and  that  also
   therefore means  that it is reserved for developers  and  experienced
   professionals having in-depth computer knowledge. Users are therefore
   encouraged to load and test the software's suitability as regards their
   requirements in conditions enabling the security of their systems and/or
   data to be ensured and,  more generally, to use and operate it in the
   same conditions as regards security.

   The fact that you are presently reading this means that you have had
   knowledge of the CeCILL license and that you accept its terms.

   /**
   * Class AUTGraph
   * Creation : 16/09/2004
   ** @version 1.0 16/09/2004
   * @author Ludovic APVRILLE
   * @see
   */

package ui.graph;

import java.util.*;
import java.io.*;

import myutil.*;

public class AUTGraph implements myutil.Graph {

    protected ArrayList<AUTTransition> transitions ;
    protected ArrayList<AUTState> states;
    protected int nbState;
    protected BufferedReader br;
    protected long nbTransition;
    protected int percentage;
    protected boolean[] hasExitTransition;
    protected boolean[] hasEntryTransition;
    protected boolean statesComputed;

    protected static String STYLE_SHEET =
        "node {" +
        "       fill-color: blue;" +
        "} " +
        //          "edge.defaultedge {" +
        //  "   shape: cubic-curve;" +
        //   "}" +
        //    "edge {shape: cubic-curve}" +
        "edge.external {" +
        "       text-style: bold;" +
        "} " +
        "node.deadlock {" +
        "       fill-color: green;" +
        "} " +
        "node.init {" +
        "       fill-color: red;" +
        "} ";

    public AUTGraph() {
        transitions = new ArrayList<AUTTransition>();
        //buildGraph(dataAUT);
    }

    public void stopBuildGraph() {
        br = null;
    }

    public int getPercentage() {
        return percentage;
    }

    public void buildGraph(String data) {
        if (data == null) {
            return;
        }

        StringReader sr = new StringReader(data);
        br = new BufferedReader(sr);
        String s, s1, s2;
        int index1;
        //int origin, destination;
        AUTTransition at;

        percentage = 0;
        int cpt, mod;

        /* read header */
        //System.out.println("Building graph");
        try {
            while((s = br.readLine()) != null) {
                index1 = s.indexOf("des");
                //System.out.println("Searching for des");
                if (index1 == 0) {
                    //System.out.println("des found");
                    s1 = s.substring(s.indexOf(',') + 1, s.length());
                    s1 = s1.substring(0, s1.indexOf(','));
                    s1 = Conversion.removeFirstSpaces(s1);
                    nbTransition = new Integer(s1).intValue();
                    s2 = s.substring(s.indexOf(",") + 1, s.indexOf(')'));
                    s2 = s2.substring(s2.indexOf(",") + 1, s2.length());
                    s2 = Conversion.removeFirstSpaces(s2);
                    nbState = new Integer(s2).intValue();
                    break;
                }
            }
        } catch (Exception e) {
            TraceManager.addDev("Exception when reading graph information: " + e.getMessage() + "\n");
            return;
        }

        String[] array;
        hasExitTransition = new boolean[nbState];
        hasEntryTransition = new boolean[nbState];

        TraceManager.addDev("NbState=" + nbState + "  NbTransition=" + nbTransition + "\n");

        /*for(cpt=0; cpt<nbState; cpt ++) {
          hasExitTransition[cpt] = false;
          hasEntryTransition[cpt] = false;
          }*/

        /* read transitions */
        try {
            cpt = 0;
            mod = Math.max(1, (int)(nbTransition / 100));


            while((s = br.readLine()) != null) {
                //System.out.println("realine:" + s);
                array = AUTGraph.decodeLine(s);
                at = new AUTTransition(array[0], array[1], array[2]);
                transitions.add(at);
                hasExitTransition[at.origin] = true;
                hasEntryTransition[at.destination] = true;
                cpt ++;
                if ((cpt % mod) == 0) {
                    percentage = (int)((cpt *100) / nbTransition);
                    //System.out.println("percentage=" + percentage + "cpt=" + cpt + "nbTransition=" + nbTransition);
                }
            }
        } catch (Exception e) {
            TraceManager.addDev("Cancelled: " + e.getMessage() + "\n");
            return;
        }
    }

    public static String[] decodeLine(String s) {
        int index1, index2;
        String s1, s2, s3;

        index1 = s.indexOf("(");
        index2 = s.indexOf(",");
        s1 = s.substring(index1+1, index2);
        s = s.substring(index2 +1, s.length());
        s = Conversion.removeFirstSpaces(s);

        // for of the action
        // , action,
        // "i(action<1,2,4>)",
        // "action<1,2,4>",

        // guillemets ?
        index1 = s.indexOf("\"");
        if (index1 > -1) {
            //System.out.println("Guillemets on " + s);
            s2 = s.substring(index1+1, s.length());
            s2 = s2.substring(0, s2.indexOf("\""));
            //System.out.println("Guillemets on " + s2);
            /*index2 = s2.indexOf("(");
              if (index2 > -1) {
              s2 = s2.substring(index2+1, s2.indexOf(")"));
              }*/
            //System.out.println("Guillemets on " + s2);

        } else {
            //System.out.println("No Guillemets on " + s);
            index1 = s.indexOf(",");
            if ((index2 = s.indexOf("(")) >= 0) {
                s2 = s.substring(index2+1, index1-2);
            } else {
                if ((index2 = s.indexOf("\"t\"")) >= 0) {
                    s2 = "t";
                } else {
                    s2 = s.substring(0, index1);
                }
            }
        }

        s = s.substring(s.indexOf(s2) + s2.length(), s.length());
        //System.out.println("s=" + s);
        index1 = s.indexOf(",");
        //index2 = s.indexOf(")");
        //s2 = s.substring(0, index1-1);
        s3 = s.substring(index1+1, s.length()-1);
        s3 = Conversion.removeFirstSpaces(s3);
        //System.out.println("s1=" + s1 + " s2=" + s2 + " s3=" + s3);

        String []array = new String[3];
        array[0] = s1;
        array[1] = s2;
        array[2] = s3;
        return array;
    }

    public int getNbOfStates() {
        return nbState;
    }

    public void setNbOfStates(int _nb) {
        nbState = _nb;
    }

    public int getNbOfTransitions() {
        //return nbTransition;
        return transitions.size();
    }

    public AUTTransition getAUTTransition(int index) {
        return transitions.get(index);
    }

    public ArrayList<AUTState> getStates() {
        return states;
    }

    public ArrayList<AUTTransition> getTransitions() {
        return transitions;
    }

    public void addTransition(AUTTransition _tr) {
        transitions.add(_tr);
        statesComputed = false;
    }



    public int getNbPotentialDeadlocks(){
        int nb = 0;

        for(int i=0; i<nbState; i++) {
            if (hasEntryTransition(i)) {
                if (!hasExitTransition(i)) {
                    nb ++;
                }
            }
        }

        return nb;
    }

    public String getActionTransition(int origin, int destination) {

        for(AUTTransition aut1 : transitions) {
            if ((aut1.origin == origin) &&  (aut1.destination == destination)){
                return aut1.transition;
            }
        }
        return "";
    }

    public boolean hasEntryTransition(int state) {
	if (hasEntryTransition == null) {
	    computeEntryExitTransitions();
	}
        return hasEntryTransition[state];
    }

    public boolean hasExitTransition(int state) {
	if (hasExitTransition == null) {
	    computeEntryExitTransitions();
	}
        return hasExitTransition[state];
    }

    public boolean hasExitTransitionTo(int state, int destination) {
        if (!hasExitTransition(state)) {
            return false;
        }


        for(AUTTransition aut1 : transitions) {
            if ((aut1.origin == state) && (aut1.destination == destination)){
                return true;
            }
        }
        return false;

    }

    /* State numbers are return under the form of int */
    /* Should be rewritten: not of high performance at all */

    public int[] getVectorPotentialDeadlocks() {
        int nbPotentialDeadlock = getNbPotentialDeadlocks();
        //System.out.println("nb of deadlocks: " + nbPotentialDeadlock);
        int[] states = new int[nbPotentialDeadlock];
        int index = 0;

        for(int i=0; i<nbState; i++) {
            if (hasEntryTransition(i)) {
                if (!hasExitTransition(i)) {
                    states[index] = i;
                    index ++;
                }
            }
        }

        return states;
    }

    public int [] shortestPathTo(int fromState, int targetState) {
        return GraphAlgorithms.ShortestPathFrom(this, fromState)[targetState].path;
    }


    public boolean hasTransitionWithAction(String action) {

        for(AUTTransition aut1 : transitions) {
            if (aut1.transition.compareTo(action) == 0){
                return true;
            }
        }
        return false;
    }

    // For Graph interface

    public int getWeightOfTransition(int originState, int destinationState) {
        if (statesComputed) {
            if (states.get(originState).hasTransitionTo(destinationState)) {
                return 1;
            }
        } else {
            if (hasExitTransitionTo(originState, destinationState)) {
                return 1;
            }
        }
        return 0;
    }

    public String toAUTStringFormat() {
        StringBuffer graph = new StringBuffer("");
        graph.append("des(0," +  nbTransition + "," + nbState + ")\n");
        for(AUTTransition aut1 : transitions) {
            graph.append("(" + aut1.origin + ",\"" + aut1.transition + "\"," + aut1.destination + ")\n");
        }
        return graph.toString();
    }


    public String toFullString() {
	StringBuffer graph = new StringBuffer("Transitions:");
	for(AUTTransition aut1 : transitions) {
	    graph.append(aut1.toString());
	}
	graph.append("\nstates:\n");
	for(AUTState str: states) {
	    graph.append(str.toString());
	}
	return graph.toString();
	
    }

    public void computeStates() {
        if (!statesComputed) {
            states = new ArrayList<AUTState>(nbState);
            AUTState state;
            for(int i=0; i<nbState; i++) {
                state = new AUTState(i);
                states.add(state);
            }

            for(AUTTransition aut1 : transitions) {
                states.get(aut1.origin).addOutTransition(aut1);
                states.get(aut1.destination).addInTransition(aut1);
            }
            statesComputed = true;
        }
    }

    public AUTState getState(int _id) {
        return states.get(_id);
    }

    public boolean areStateComputed() {
        return statesComputed;
    }

    public HashSet<String> getAllActions() {
        HashSet<String> hs = new HashSet<String>();
        for(AUTTransition tr: transitions) {
            hs.add(tr.transition);
        }
        return hs;
    }


    public void reinitMet() {
        for(AUTState state: states) {
            state.met = false;
        }
    }

    public AUTState findFirstOriginState() {
        AUTState state;

        for(int i=0; i<states.size(); i++) {
            state = states.get(i);
            //System.out.println("id=" + state.id + " transitions to me = " +state.inTransitions.size());
            if (state.inTransitions.size() == 0) {
                return state;
            }
        }

        return null;
    }

    public void putTransitionsFromInitFirst() {
        ArrayList<AUTTransition> tmp = new ArrayList<AUTTransition>();

        for(AUTTransition aut1 : transitions) {
            if (aut1.origin == 0) {
                tmp.add(aut1);
            }
        }

        for(AUTTransition aut2 : tmp) {
            transitions.remove(aut2);
            transitions.add(0, aut2);
        }
    }

    public void display() {
        AUTGraphDisplay display = new AUTGraphDisplay(this);
        display.display();
    }


    public AUTGraph cloneMe() {
        AUTGraph newGraph = new AUTGraph();
        newGraph.setNbOfStates(getNbOfStates());
        for(AUTTransition tr: transitions) {
            AUTTransition newTr = new AUTTransition(tr.origin, tr.transition, tr.destination);
            newGraph.addTransition(newTr);
        }
        newGraph.computeStates();
        return newGraph;
    }


    public void minimizeRemoveInternal() {
        String s = "tau";

        // mark all transitions as non tau
        for(AUTTransition tr: transitions) {
            tr.isTau = false;
        }

        // Mark all tau transitions as tau
        for(AUTTransition tr: transitions) {

            if (tr.transition.startsWith("i(")) {
                tr.isTau = true;
                tr.transition = s;
            }

        }

        minimizeTau();
    }


    public void minimize(String [] tauTransitions) {
        String s = "tau";

        // mark all transitions as non tau
        for(AUTTransition tr: transitions) {
            tr.isTau = false;
        }

        // Mark all tau transitions as tau
        for(AUTTransition tr: transitions) {
            for (int i=0; i<tauTransitions.length; i++) {
                if (tr.transition.compareTo(tauTransitions[i]) == 0) {
                    tr.isTau = true;
                    tr.transition = s;
                }
            }
        }

        minimizeTau();

    }

    public void minimizeTau() {
        boolean modif = true;

	//TraceManager.addDev(toFullString());
	
	factorizeNonTauTransitions();

	
        /*while(modif) {
            modif = removeOnlyOneTauTr();
            if (! modif) {
                modif = removeMultipleTauOutputTr();
                if (! modif) {
                    modif = removeTauWithOneFollower();
                    if (! modif) {
                        modif = removeSimilarTransitions();
                    }
                }
            }
	    }*/

	partitionGraph();
	
        statesComputed = false;
    }

    // Remove transition going from one state with only one tau transition as output
    private boolean removeOnlyOneTauTr() {
        AUTTransition tr;
        ArrayList<AUTState> toRemoveStates = new ArrayList<AUTState>();
        // Remove in case state with one outgoing and outgoing is tau -> remove tr
        for(AUTState st: states) {
            if (st.outTransitions.size() == 1) {
                tr = st.outTransitions.get(0);
                if (tr.isTau) {
                    transitions.remove(tr);
                    st.outTransitions.clear();


                    AUTState st1 = states.get(tr.destination);
                    if (st1 != st) {
                        toRemoveStates.add(st1);
                        //TraceManager.addDev("Removing state " + st1.id);

                        // Must put all incoming transition to the first state
                        st1.inTransitions.remove(tr);
                        for(AUTTransition trM: st1.inTransitions) {
                            trM.destination = st.id;
                            st.inTransitions.add(trM);
                            //TraceManager.addDev("New in transitions " + trM);
                        }
                        st1.inTransitions.clear();

                        // Out transitions
                        st.outTransitions.clear();
                        for(AUTTransition trM: st1.outTransitions) {
                            st.outTransitions.add(trM);
                            trM.origin = st.id;
                            //TraceManager.addDev("New out transitions " + trM);
                        }
                        st1.outTransitions.clear();
                        break;
                    }
                }
            }
        }

        // Remove all states and adapt the id in the graph
        if (toRemoveStates.size() > 0) {
            removeStates(toRemoveStates);
            return true;
        }

        return false;
    }


    // Rework states with at least 2 tau transitions
    private boolean removeMultipleTauOutputTr() {
        AUTTransition tr1, tr2, trtmp;
        AUTState st1, st2, sttmp;
        ArrayList<AUTState> toRemoveStates = new ArrayList<AUTState>();
        AUTTransition [] ret;
        boolean modif = false;

        // Remove in case state with one outgoing and outgoing is tau -> remove transition
        for(AUTState st: states) {
            ret = st.getAtLeastTwoOutTauTransitions();
            if (ret != null) {
                tr1 = ret[0];
                tr2 = ret[1];
                tr2 = st.outTransitions.get(1);
                st1 = states.get(tr1.destination);
                st2 = states.get(tr2.destination);

                // Same states
                if (st1 == st2) {
                    //We can simply remove the transition
                    transitions.remove(tr2);
                    st.outTransitions.remove(tr2);
                    modif = true;
                }

                // We can merge st1 or st2 because one has no other incoming transition than
                // the tau transition
                else if ((st1.inTransitions.size() == 1) && (st2.inTransitions.size() == 1)) {
                    //We can remove st2 and the tau transition
                    toRemoveStates.add(st2);
                    transitions.remove(tr2);
                    st.outTransitions.remove(tr2);

                    // All transitions leaving st2 must now leave from st1 as well
                    for (AUTTransition trf: st2.outTransitions) {
                        trf.origin = st1.id;
                        st1.outTransitions.add(trf);
                    }
                }

            }
        }

        // Remove all states and adapt the id in the graph
        if (toRemoveStates.size() > 0) {
            removeStates(toRemoveStates);
            modif = true;
        }



        return modif;
    }

    // Rework states with only one tau before, and only one action after
    private boolean removeTauWithOneFollower() {
        AUTTransition tr1, tr2;
        AUTState st1, st2;
        ArrayList<AUTState> toRemoveStates = new ArrayList<AUTState>();
        boolean modif = false;

        // Remove stgate in case state with one outgoing and outgoing is tau
        for(AUTState st: states) {
            if (st.hasOneIncomingTauAndOneFollower()) {
                //We can remove the previous tau transaction, and the current state
                tr1 = st.inTransitions.get(0);
                st1 = states.get(tr1.origin);
                if (st1 != st) {
                    tr2 = st.outTransitions.get(0);
                    tr2.origin = st1.id;
                    st1.outTransitions.remove(tr1);
                    st1.outTransitions.add(tr2);
                    transitions.remove(tr1);
                    toRemoveStates.add(st);
                    break;
                }
            }

        }

        // Remove all states and adapt the id in the graph
        if (toRemoveStates.size() > 0) {
            removeStates(toRemoveStates);
            modif = true;
        }



        return modif;
    }
    

    private boolean removeSimilarTransitions() {
        boolean modif = false;

        // Remove tr if it is duplicated
        for(AUTState st: states) {

	    // May modify the outTransitions list, and result in exception.
	    // The try .. catch clause protects from this
            try {
                if (st.outTransitions.size() > 1) {
                    for(int i=0; i<st.outTransitions.size(); i++) {
                        for(int j=i+1; j<st.outTransitions.size(); j++) {
                            AUTTransition tri = st.outTransitions.get(i);
                            AUTTransition trj = st.outTransitions.get(j);
                            if (tri.destination == trj.destination) {
                                if (tri.transition.compareTo(trj.transition) == 0) {
                                    modif = true;
                                    //We remove trj
                                    st.outTransitions.remove(trj);
                                    transitions.remove(trj);
                                    i--;
                                    j--;
                                }
                            }
                        }
                    }


                }
            } catch (Exception e) {}
        }

        return modif;
    }


    private void removeStates(ArrayList<AUTState> toRemoveStates) {

	if (toRemoveStates.size() > 0) {
	    hasExitTransition = null;
	    hasEntryTransition = null;
	}
	
        // Remove all states and adapt the id in the graph
	//TraceManager.addDev("nbState=" + nbState + " states size = " + states.size());
	
        for(AUTState str: toRemoveStates) {
	    // We need to remove all transitions of the removed state
	    //TraceManager.addDev("Removing transitions of state:" + str.id + "\n" + toFullString());
	    for(AUTTransition trin: str.inTransitions) {
		transitions.remove(trin);
	    }
	    for(AUTTransition trout: str.outTransitions) {
		transitions.remove(trout);
	    }

	    for(AUTState state: states) {
		state.removeAllTransitionsWithId(str.id);
	    }

	    //TraceManager.addDev("Done removing transitions of state:" + str.id + "\n" + toFullString());
	    
            // Last state of the array?
            if (str.id == (nbState - 1)) {
                //TraceManager.addDev("Last state " + str.id);
                nbState --;
                states.remove(str.id);

                // str not at the end: we replace it with the last state
                // We need to accordingly update
            } else {

                AUTState moved = states.get(nbState-1);
                //TraceManager.addDev("Moving state " + moved.id +  " to index " + str.id);
                states.set(str.id, moved);
                states.remove(nbState-1);
                nbState --;
		//TraceManager.addDev("nbState=" + nbState + " states size = " + states.size());
		/*AUTTransition tt = findTransitionWithId(nbState);
		if (tt != null) {
                    TraceManager.addDev("1) Transition with id not normal" + tt);
		    }*/
		//TraceManager.addDev("Update id\n" + toAUTStringFormat());
		moved.updateID(str.id);
                /*tt = findTransitionWithId(nbState);
                if (tt != null) {
                    TraceManager.addDev("2) Transition with id not normal" + tt);
		    }*/
            }
	    //TraceManager.addDev(toFullString());

        }
    }

    // Removes all tau transition of a state, replacing them with reachable non tau transitions
    // A tau transition reaching a end state cannot be removed but can be replaced with a unique transition
    private void factorizeNonTauTransitions() {
	boolean modif = false;
	boolean endState = false;
	// met is used to specify states that have a tau-path to a termination state
	for(AUTState st1: states) {
	    st1.met = false;
	}
	
        // Remove tr if it is duplicated
        for(AUTState st: states) {
	    // We ignore states with no input tr apart from the start state (id 0)
	    //TraceManager.addDev("0. state " + st.id);
	    if ((st.id == 0) || (st.getNbInTransitions() > 0)) {
		//TraceManager.addDev("  1. state " + st.id);
		if (st.hasOutputTauTransition()) {
		    //TraceManager.addDev("  2. state " + st.id);
		    LinkedList<AUTTransition> nonTauTransitions = new LinkedList<AUTTransition>();
		    boolean canReachAnEndStateWithTau = getAllNonTauTransitionsFrom(st, nonTauTransitions);

		    //TraceManager.addDev("State " + st.id + " has the following real transitions:");
		    /*for(AUTTransition tr: nonTauTransitions) {
			TraceManager.addDev("\t" + tr);
			}*/
		    
		    st.met = canReachAnEndStateWithTau;
		    endState = endState || canReachAnEndStateWithTau;
		    
		    // Create these transitions in st if not yet existing
		    //TraceManager.addDev("Remove tau\n" + toFullString());
		    st.removeAllOutTauTransitions(transitions, states);
		    //TraceManager.addDev("Done remove tau. create trans\n" + toFullString());
		    st.createTransitionsButNotDuplicate(nonTauTransitions, states, transitions);
		    //TraceManager.addDev("Done create trans\n" + toFullString());
		}
	    }
	}

	// If end state: we must create a new end state, and all "met" states should have a tau transition
	// to this state
	if (endState) {
	    int newId = states.size();
	    AUTState endSt = new AUTState(newId);
	    states.add(endSt);
	    nbState = states.size();
	    for(AUTState st: states) {
		if (st.met) {
		    AUTTransition tr = new AUTTransition(st.id, "tau", endSt.id);
		    tr.isTau = true;
		    transitions.add(tr);
		    st.addOutTransition(tr);
		    endSt.addInTransition(tr);
		}
		st.met = false;
	    }
	}
	//TraceManager.addDev(toFullString());

	// Remove all non reachable state
	removeAllNonReachableStates();


	// Print graph in AUT
	//TraceManager.addDev(toAUTStringFormat());

	
    }

    private boolean getAllNonTauTransitionsFrom(AUTState st, LinkedList<AUTTransition> nonTauTransitions) {
	LinkedList<AUTState> metStates = new LinkedList<AUTState>();
	//metStates.add(st);

	return getAllNonTauTransitionsIterative(st, metStates, nonTauTransitions);
	//return getAllNonTauTransitionsRecursive(st, metStates, nonTauTransitions);
    }


    private boolean getAllNonTauTransitionsRecursive(AUTState st, LinkedList<AUTState> metStates, LinkedList<AUTTransition> nonTauTransitions) {
	if (metStates.contains(st)) {
	    return false;
	}

	if (st.getNbOutTransitions() == 0) {
	    return true;
	}

	boolean ret = false;
	for(AUTTransition at: st.outTransitions) {
	    if (!(at.isTau)) {
		nonTauTransitions.add(at);		
	    } else {
		ret = ret || getAllNonTauTransitionsRecursive(states.get(at.destination), metStates, nonTauTransitions);
	    }
	}
	
	return ret;
    }


    private boolean getAllNonTauTransitionsIterative(AUTState _st, LinkedList<AUTState> metStates, LinkedList<AUTTransition> nonTauTransitions) {

	boolean ret = false;
	
	LinkedList<AUTState> toExplore = new LinkedList<AUTState>();
	LinkedList<AUTState> toExploreTmp = new LinkedList<AUTState>();
	toExplore.add(_st);
	
	while (toExplore.size() > 0) {
	    toExploreTmp.clear();
	    for(AUTState st: toExplore) {
		if (!(metStates.contains(st))) {
		    metStates.add(st);
		    if (st.getNbOutTransitions() == 0) {
			ret = true;
		    } else {
			for(AUTTransition at: st.outTransitions) {
			    if (!(at.isTau)) {
				nonTauTransitions.add(at);		
			    } else {
				toExploreTmp.add(states.get(at.destination));
			    }
			}
		    }
		    
		}
	    } // for
	    toExplore.clear();
	    toExplore.addAll(toExploreTmp);
	    
	}// While

	return ret;
    }
    
    private AUTTransition findTransitionWithId(int id) {
        for (AUTTransition tr: transitions) {
            if ((tr.origin == id) || (tr.destination == id)) {
                return tr;
            }
        }
        return null;
    }


    private void removeAllNonReachableStates() {
	// reset met of states
	for(AUTState st1: states) {
	    st1.met = false;
	}

	int cpt = 0;

	LinkedList<AUTState> statesToConsider = new LinkedList<AUTState>();
	LinkedList<AUTState> nextStatesToConsider = new LinkedList<AUTState>();
	statesToConsider.add(states.get(0));

	while(statesToConsider.size() > 0) {
	    nextStatesToConsider.clear();
	    for(AUTState st: statesToConsider) {
		st.met = true;
		cpt ++;
		for(AUTTransition tr: st.outTransitions) {
		    AUTState s = states.get(tr.destination);
		    if (!(s.met)) {
			nextStatesToConsider.add(s);
		    }
		}
	    }
	    statesToConsider.clear();
	    statesToConsider.addAll(nextStatesToConsider);
	}

	//TraceManager.addDev("Found " + cpt + " reachable states");
	ArrayList<AUTState> toRemoveStates = new ArrayList<AUTState>();
	for(AUTState st2: states) {
	    if (!(st2.met)) {
		toRemoveStates.add(st2);
		//TraceManager.addDev("Removing state: " + st2.id);
	    }
	}

	removeStates(toRemoveStates);
	
    }


    private void computeEntryExitTransitions() {
	hasExitTransition = new boolean[nbState];
        hasEntryTransition = new boolean[nbState];

	for(AUTTransition t: transitions) {
	    hasExitTransition[t.origin] = true;
	    hasEntryTransition[t.destination] = true;
	}
    }


    public void partitionGraph() {
	
	// Create the alphabet
	HashMap<String, AUTElement> alphabet = new HashMap<String, AUTElement>();
	for(AUTTransition tr: transitions) {
	    AUTElement tmp = alphabet.get(tr.transition);
	    if (tmp == null) {
		AUTElement elt = new AUTElement(tr.transition);
		alphabet.put(tr.transition, elt);
		tr.elt = elt;
	    } else {
		tr.elt = tmp;
	    }
	    //TraceManager.addDev("Transition "+ tr + " has element " + tr.elt);
	}

	List<AUTElement> sortedAlphabet = new ArrayList<AUTElement>(alphabet.values());
	Collections.sort(sortedAlphabet);
	
	TraceManager.addDev("Alphabet size:" + alphabet.size());