/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999-2002 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xerces" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.xerces.impl.dtd.models;

import org.apache.xerces.impl.dtd.XMLContentSpec;
import org.apache.xerces.xni.QName;

/**
 * Content model leaf node.
 *
 * @version $Id: CMLeaf.java,v 1.2 2002/01/29 01:15:10 lehors Exp $
 */
public class CMLeaf 
    extends CMNode {

    //
    // Data
    //

    /** This is the element that this leaf represents. */
    private QName fElement = new QName();

    /**
     * Part of the algorithm to convert a regex directly to a DFA
     * numbers each leaf sequentially. If its -1, that means its an
     * epsilon node. Zero and greater are non-epsilon positions.
     */
    private int fPosition = -1;

    //
    // Constructors
    //

    /** Constructs a content model leaf. */
    public CMLeaf(QName element, int position)  {
        super(XMLContentSpec.CONTENTSPECNODE_LEAF);

        // Store the element index and position
        fElement.setValues(element);
        fPosition = position;
    }

    /** Constructs a content model leaf. */
    public CMLeaf(QName element)  {
        super(XMLContentSpec.CONTENTSPECNODE_LEAF);

        // Store the element index and position
        fElement.setValues(element);
    }

    //
    // Package methods
    //

    final QName getElement()
    {
        return fElement;
    }

    final int getPosition()
    {
        return fPosition;
    }

    final void setPosition(int newPosition)
    {
        fPosition = newPosition;
    }

    //
    // CMNode methods
    //

    // package

    public boolean isNullable() 
    {
        // Leaf nodes are never nullable unless its an epsilon node
        return (fPosition == -1);
    }

    public String toString()
    {
        StringBuffer strRet = new StringBuffer(fElement.toString());
        strRet.append(" (");
        strRet.append(fElement.uri);
        strRet.append(',');
        strRet.append(fElement.localpart);
        strRet.append(')');
        if (fPosition >= 0)
        {
            strRet.append
            (
                " (Pos:"
                + new Integer(fPosition).toString()
                + ")"
            );
        }
        return strRet.toString();
    }

    // protected

    protected void calcFirstPos(CMStateSet toSet) 
    {
        // If we are an epsilon node, then the first pos is an empty set
        if (fPosition == -1)
            toSet.zeroBits();

        // Otherwise, its just the one bit of our position
        else
            toSet.setBit(fPosition);
    }

    protected void calcLastPos(CMStateSet toSet) 
    {
        // If we are an epsilon node, then the last pos is an empty set
        if (fPosition == -1)
            toSet.zeroBits();

        // Otherwise, its just the one bit of our position
        else
            toSet.setBit(fPosition);
    }

} // class CMLeaf


