src/org/apache/xpath/axes/ChildWalkerOneStep.java

/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 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 "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
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 *
 * 5. Products derived from this software may not be called "Apache",
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 * ====================================================================
 *
 * 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, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.xpath.axes;

//import org.w3c.dom.Node;
//import org.w3c.dom.traversal.NodeFilter;
import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMFilter;
import org.apache.xml.dtm.DTMIterator;

import org.apache.xpath.patterns.NodeTestFilter;

/**
 * <meta name="usage" content="advanced"/>
 * Walker to use when we only have one step, but it has a predicate.
 */
public class ChildWalkerOneStep extends AxesWalker
{

  /**
   * Construct an AxesWalker using a LocPathIterator.
   *
   * @param locPathIterator The location path iterator that 'owns' this walker.
   */
  public ChildWalkerOneStep(LocPathIterator locPathIterator)
  {
    super(locPathIterator);
  }

  /**
   * Tell what's the maximum level this axes can descend to.
   *
   * @return An estimation of the maximum level this axes can descend to.
   */
  protected int getLevelMax()
  {
    return getDTM(m_root).getLevel(m_root);
  }

  /**
   * Get the next node in document order on the axes.
   *
   * @return The next node in the walk, or null.
   */
  public int nextNode()
  {

    int next;

    if (m_root == m_currentNode)
    {
      next = getDTM(m_currentNode).getFirstChild(m_currentNode);
      m_isFresh = false;
    }
    else
      next = getDTM(m_currentNode).getNextSibling(m_currentNode);

    if (DTM.NULL != next)
    {
      m_currentNode = next;

      while (acceptNode(next) != DTMIterator.FILTER_ACCEPT)
      {
        next = getDTM(next).getNextSibling(next);

        if (DTM.NULL != next)
          m_currentNode = next;
        else
        {
          this.m_isDone = true;

          break;
        }
      }
    }
    else
      this.m_isDone = true;

    return next;
  }
}