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Location.java

package edu.ksu.cis.bandera.bir;

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Bandera, a Java(TM) analysis and transformation toolkit           *
 * Copyright (C) 1998, 1999   James Corbett (corbett@hawaii.edu)     *
 * All rights reserved.                                              *
 *                                                                   *
 * This work was done as a project in the SAnToS Laboratory,         *
 * Department of Computing and Information Sciences, Kansas State    *
 * University, USA (http://www.cis.ksu.edu/santos).                  *
 * It is understood that any modification not identified as such is  *
 * not covered by the preceding statement.                           *
 *                                                                   *
 * This work is free software; you can redistribute it and/or        *
 * modify it under the terms of the GNU Library General Public       *
 * License as published by the Free Software Foundation; either      *
 * version 2 of the License, or (at your option) any later version.  *
 *                                                                   *
 * This work is distributed in the hope that it will be useful,      *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of    *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU *
 * Library General Public License for more details.                  *
 *                                                                   *
 * You should have received a copy of the GNU Library General Public *
 * License along with this toolkit; if not, write to the             *
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,      *
 * Boston, MA  02111-1307, USA.                                      *
 *                                                                   *
 * Java is a trademark of Sun Microsystems, Inc.                     *
 *                                                                   *
 * To submit a bug report, send a comment, or get the latest news on *
 * this project and other SAnToS projects, please visit the web-site *
 *                http://www.cis.ksu.edu/santos                      *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
import ca.mcgill.sable.util.*;

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

/**
 * A Location represents a control point in a thread from which 
 * guarded transformations may be taken. 
 * <p>
 * Each location has:
 * <ul>
 * <li> An integer id (this is negative before the locations are numbered,
 * positive afterwards).
 * <li> An optional label for printing (constructed from the id if absent).
 * <li> The thread to which it belongs.
 * <li> An integer mark for use in searches.
 * <li> Vectors of transformations into and out of the location.
 * <li> A vector of local state variables that are live at the location.
 * </ul>
 */

public class Location {
    
    int id;        // location id
    BirThread thread; // thread we're contained in
    TransVector inTrans;     // incoming Transformations
    TransVector outTrans;    // outgoing Transformations
    StateVarVector liveVars;
    int mark;         // Location mark (for DFS)
    String label;

    static int markCount = 0;   // mark generator
    static int locCount = 0;
 
    public Location(BirThread thread) {
        this.thread = thread;
    this.inTrans = new TransVector();
    this.outTrans = new TransVector();
    this.mark = 0;
    this.id = - (++locCount);
    }
    /**
     * Add a transformation out of the location.
     * @param toLoc target of transformation
     * @param guard guard expression
     * @param actions vector of actions
     * @return the new transformation
     */
    public Transformation addTrans(Location toLoc, Expr guard, 
             ActionVector actions) {
    Transformation trans = 
        new Transformation(this, toLoc, guard, actions);
    outTrans.addElement(trans);
    toLoc.inTrans.addElement(trans);
    thread.getSystem().addTrans(trans);
    return trans;
    }
    // Accessors
    public int getId() { return id; }
    public TransVector getInTrans() { return inTrans; }
    public String getLabel() { return (label != null) ? label : "s" + id; }
    public StateVarVector getLiveVars() { return liveVars; }
    public int getMark() { return mark; }
    public static int getNewMark() { return ++markCount; }
    public TransVector getOutTrans() { return outTrans; }
    public BirThread getThread() { return thread; }
    /** 
     * A location is visible if:
     * <ul> 
     * <li> it has no incoming transformations, or
     * <li> it has no outgoing transformations, or
     * <li> some incoming transformation is visible.
     * </ul>
     */
    public boolean isVisible() {
    if (inTrans.size() == 0)
        return true;
    if (outTrans.size() == 0)
        return true;
    for (int i = 0; i < inTrans.size(); i++)
        if (inTrans.elementAt(i).isVisible())
        return true;
    return false;
    }
    public void setId(int id) { this.id = id; }
    public void setLabel(String label) { this.label = label; }
    public void setLiveVars(StateVarVector liveVars) { 
    this.liveVars = liveVars; 
    }
    public void setMark(int mark) { this.mark = mark; }
    // Printing
    public String toString() {
    return "<Loc " + id + ">";
    }
}

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