icltraversal.java

SRI international 发布的OAA框架软件

// $CALOLSI$
/*
 * #=========================================================================
 * # Copyright 2004 SRI International.  All rights reserved.
 * #
 * # The material contained in this file is confidential and proprietary to SRI
 * # International and may not be reproduced, published, or disclosed to others
 * # without authorization from SRI International.
 * #
 * # DISCLAIMER OF WARRANTIES
 * #
 * # SRI International MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE
 * # SUITABILITY OF THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT
 * # LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * # PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SRI International SHALL NOT BE
 * # LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
 * # OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES
 * #=========================================================================
 * Author : evans
 * Date: May 11, 2004
 * Time: 6:00:30 PM
 */
package com.sri.oaa2.mapper;

import java.util.LinkedList;
import java.util.List;

import com.sri.oaa2.icl.*;

/**
 * Traverses an ICL tree and calls back to an IclVisitor interface.
 * This class is meant to be subclassed with the visit() methods overridden.
 */
public class IclTraversal
{
    private IclTerm root;
    private IclTerm parent;
    private int index = -1;


    public final void traverse(IclTerm icl)
            throws MappingException
    {
        traverse(icl, null, -1);
    }

    public final void traverse(IclTerm icl, IclTerm parent, int childIndex)
            throws MappingException
    {
        try
        {
            root = icl;
            this.parent = parent;
            index = childIndex;
            if(visit(icl)) traverseChildren(icl);
        }
        finally
        {
            root = null;
        }
    }

    protected boolean visit(IclTerm icl)
            throws MappingException
    {
        if(icl.isVar())
            return visit((IclVar)icl);
        else if(icl.isStr())
            return visit((IclStr)icl);
        else if(icl.isStruct())
            return visit((IclStruct)icl);
        else if(icl.isInt())
            return visit((IclInt)icl);
        else if(icl.isFloat())
            return visit((IclFloat)icl);
        else if(icl.isList())
            return visit((IclList)icl);
        else if(icl.isGroup())
            return visit((IclGroup)icl);
        else
            return true;
    }

    protected boolean visit(IclVar icl)
            throws MappingException
    {
        return true;
    }

    protected boolean visit(IclStr icl)
            throws MappingException
    {
        return true;
    }

    protected boolean visit(IclStruct icl)
            throws MappingException
    {
        return true;
    }

    protected boolean visit(IclInt icl)
            throws MappingException
    {
        return true;
    }

    protected boolean visit(IclFloat icl)
            throws MappingException
    {
        return true;
    }

    protected boolean visit(IclList icl)
            throws MappingException
    {
        return true;
    }

    protected boolean visit(IclGroup icl)
            throws MappingException
    {
        return true;
    }

    /**
     * Replaces the currently visited node.
     *
     * @param icl
     */
    protected final void replace(IclTerm icl)
            throws MappingException
    {
        if(parent != null)
            parent.replaceElement(index, icl);
        else
            throw new MappingException("Cannot replace root element of " + root.toString() + " with " + icl);
    }

    /**
     * Remove the currently visited node.
     */
    protected final void remove()
            throws MappingException
    {
        if(parent != null)
        {
            parent.removeElement(index);
            index--;
        }
        else
            throw new MappingException("Cannot remove root element of " + root.toString());
    }

    ///////////////////////////////////////////////////////

    private void traverseChildren(IclTerm icl)
            throws MappingException
    {
        List traversalQueue = new LinkedList();
        traversalQueue.add(icl);
        while(traversalQueue.size() > 0)
        {
            parent = (IclTerm)traversalQueue.remove(0);
            for(index = 0; index < parent.getNumChildren(); index++)
            {
                IclTerm child = parent.getTerm(index);
                if(visit(child)) traversalQueue.add(child);
            }
        }
    }
}