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InstanceVariantManager.java

package edu.ksu.cis.bandera.bofa;

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Bandera, a Java(TM) analysis and transformation toolkit           *
 * Copyright (C) 1998, 1999                                          *
 * John Hatcliff (hatcliff@cis.ksu.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.soot.*;
import ca.mcgill.sable.util.*;

/* 
 * InstanceVariantManager.java 
 * $Id: InstanceVariantManager.java,v 1.1.1.1 2002/01/24 03:42:08 pserver Exp $
 */

/**
 * This class that manages the instance variable variants.
 * 
 * @author <A HREF="http://www.cis.ksu.edu/~hatcliff">John Hatcliff</A>
 * @author
 * <a href="http://www.cis.ksu.edu/~rvprasad">Venkatesh Prasad Ranganath</a>
 * @version $Name:  $($Revision: 1.1.1.1 $)
 */
public class InstanceVariantManager
{
    /** 
     * Manager of the indices associated with instance variants. 
     *
     */
    private static InstanceIndexManager instanceIndexManager;

    /** 
     * Mapping from field to instance indices map. 
     *
     */
    private static Map                  instanceMap;

    /**
     * Provides the set of instance variables managed.
     *
     * @return set of instance variants managed. 
     */
    public static Set getFields()
    {
        return instanceMap.keySet();
    }
    /**
     * Provides the collection of instance variants managed.
     *
     * @param sootField a <code>SootField</code> value
     * @return collection of instance variants managed.
     */
    public static Collection getVariants(SootField sootField)
    {
        return ((Map) instanceMap.get(sootField)).values();
    }
    /**
     * Initialize the Manager.
     * @param instanceIndexManager the manager who will provide the indices to
     * get to the instance variants.  
     */
    public static void init(InstanceIndexManager instanceIndexManager) {
        InstanceVariantManager.instanceIndexManager = instanceIndexManager;
        InstanceVariantManager.instanceMap          = new HashMap();
    }
    /**
     * Reset the data structures of the manager.
     *
     */
    public static void reset() {
        if (instanceMap != null) {
            instanceMap.clear();
        } // end of if (instanceMap != null)
        if (instanceIndexManager != null) {
            instanceIndexManager.reset();
        } // end of if (instanceIndexManager != null)
    }
    /**
     * Select the variant corresponding to the instance variable.  If none
     * exists, then a new one is created.  In this implementation only one
     * instance variant is associated with one field variable of a class.
     *
     * @param sootField the field for which variant is requested.
     * @return the corresponding variant. 
     */
    public static InstanceVariant select(SootField  sootField)
    {
        Map             indexMap;
        Index           instanceIndex;
        InstanceVariant instanceVariant;
        FGNodeField     node;
      
        // compute index based on context info 
        instanceIndex = instanceIndexManager.select();

        if (instanceMap.containsKey(sootField)) {
            // if field is already registered, compute variant index, and
            // see if it is registered.
            indexMap = (Map) instanceMap.get(sootField);

            if (indexMap.containsKey(instanceIndex)) {
                // if variant index is registered, then return variant
                instanceVariant = (InstanceVariant) indexMap.get(instanceIndex);
            } else {
                // index was not registered, so make new instance and register.
                node = new FGNodeField(sootField);
                instanceVariant = new InstanceVariant(sootField,
                                                      instanceIndex,
                                                      node);
                indexMap.put(instanceIndex,instanceVariant);
            }
        } else {
            // if instance field is not registered, then register it with an
            // index map with the current variant
            indexMap = new HashMap();
            node = new FGNodeField(sootField);
            instanceVariant = new InstanceVariant(sootField,
                                                  instanceIndex,
                                                  node);
            indexMap.put(instanceIndex,instanceVariant);
            instanceMap.put(sootField,indexMap);
        }
        return instanceVariant;
    }
}

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