code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the  "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * $Id$
   */
  package org.apache.xml.dtm.ref;
  
  import org.apache.xml.dtm.DTM;
  import org.apache.xml.utils.NodeConsumer;
  import org.apache.xml.utils.XMLString;
  
  import org.xml.sax.ContentHandler;
  import org.xml.sax.ext.LexicalHandler;
  
  /**
   * This class does a pre-order walk of the DTM tree, calling a ContentHandler
   * interface as it goes. As such, it's more like the Visitor design pattern
   * than like the DOM's TreeWalker.
   *
   * I think normally this class should not be needed, because 
   * of DTM#dispatchToEvents.
   * @xsl.usage advanced
   */
  public class DTMTreeWalker
  {
  
    /** Local reference to a ContentHandler          */
    private ContentHandler m_contentHandler = null;
  
    /** DomHelper for this TreeWalker          */
    protected DTM m_dtm;
    
    /**
     * Set the DTM to be traversed.
     * 
     * @param dtm The Document Table Model to be used.
     */
    public void setDTM(DTM dtm)
    {
      m_dtm = dtm;
    }
  
    /**
     * Get the ContentHandler used for the tree walk.
     *
     * @return the ContentHandler used for the tree walk
     */
    public ContentHandler getcontentHandler()
    {
      return m_contentHandler;
    }
    
    /**
     * Set the ContentHandler used for the tree walk.
     *
     * @param ch the ContentHandler to be the result of the tree walk.
     */
    public void setcontentHandler(ContentHandler ch)
    {
      m_contentHandler = ch;
    }
  
    
    /**
     * Constructor.
     */
    public DTMTreeWalker()
    {
    }
    
    /**
     * Constructor.
     * @param   contentHandler The implemention of the
     * contentHandler operation (toXMLString, digest, ...)
     */
    public DTMTreeWalker(ContentHandler contentHandler, DTM dtm)
    {
      this.m_contentHandler = contentHandler;
      m_dtm = dtm;
    }
    
    /** Perform a non-recursive pre-order/post-order traversal,
     * operating as a Visitor. startNode (preorder) and endNode
     * (postorder) are invoked for each node as we traverse over them,
     * with the result that the node is written out to m_contentHandler.
     *
     * @param pos Node in the tree at which to start (and end) traversal --
     * in other words, the root of the subtree to traverse over.
     *
     * @throws TransformerException */
    public void traverse(int pos) throws org.xml.sax.SAXException
    {
      // %REVIEW% Why isn't this just traverse(pos,pos)?
  
      int top = pos;		// Remember the root of this subtree
  
      while (DTM.NULL != pos)
      {
        startNode(pos);
        int nextNode = m_dtm.getFirstChild(pos);
        while (DTM.NULL == nextNode)
        {
          endNode(pos);
  
          if (top == pos)
            break;
  
          nextNode = m_dtm.getNextSibling(pos);
  
          if (DTM.NULL == nextNode)
          {
            pos = m_dtm.getParent(pos);
  
            if ((DTM.NULL == pos) || (top == pos))
            {
              // %REVIEW% This condition isn't tested in traverse(pos,top)
              // -- bug?
              if (DTM.NULL != pos)
                endNode(pos);
  
              nextNode = DTM.NULL;
  
              break;
            }
          }
        }
  
        pos = nextNode;
      }
    }
  
    /** Perform a non-recursive pre-order/post-order traversal,
     * operating as a Visitor. startNode (preorder) and endNode
     * (postorder) are invoked for each node as we traverse over them,
     * with the result that the node is written out to m_contentHandler.
     *
     * @param pos Node in the tree where to start traversal
     * @param top Node in the tree where to end traversal.
     * If top==DTM.NULL, run through end of document.
     *
     * @throws TransformerException
     */
    public void traverse(int pos, int top) throws org.xml.sax.SAXException
    {
      // %OPT% Can we simplify the loop conditionals by adding:
      //		if(top==DTM.NULL) top=0
      // -- or by simply ignoring this case and relying on the fact that
      // pos will never equal DTM.NULL until we're ready to exit?
  
      while (DTM.NULL != pos)
      {
        startNode(pos);
        int nextNode = m_dtm.getFirstChild(pos);
        while (DTM.NULL == nextNode)
        {
          endNode(pos);
  
          if ((DTM.NULL != top) && top == pos)
            break;
  
          nextNode = m_dtm.getNextSibling(pos);
  
          if (DTM.NULL == nextNode)
          {
            pos = m_dtm.getParent(pos);
  
            if ((DTM.NULL == pos) || ((DTM.NULL != top) && (top == pos)))
            {
              nextNode = DTM.NULL;
  
              break;
            }
          }
        }
  
        pos = nextNode;
      }
    }
  
    /** Flag indicating whether following text to be processed is raw text          */
    boolean nextIsRaw = false;
    
    /**
     * Optimized dispatch of characters.
     */
    private final void dispatachChars(int node)
       throws org.xml.sax.SAXException
    {
      m_dtm.dispatchCharactersEvents(node, m_contentHandler, false);
    }
  
    /**
     * Start processing given node
     *
     *
     * @param node Node to process
     *
     * @throws org.xml.sax.SAXException
     */
    protected void startNode(int node) throws org.xml.sax.SAXException
    {
  
      if (m_contentHandler instanceof NodeConsumer)
      {
        // %TBD%
  //      ((NodeConsumer) m_contentHandler).setOriginatingNode(node);
      }
  
      switch (m_dtm.getNodeType(node))
      {
      case DTM.COMMENT_NODE :
      {
        XMLString data = m_dtm.getStringValue(node);
  
        if (m_contentHandler instanceof LexicalHandler)
        {
          LexicalHandler lh = ((LexicalHandler) this.m_contentHandler);
          data.dispatchAsComment(lh);
        }
      }
      break;
      case DTM.DOCUMENT_FRAGMENT_NODE :
  
        // ??;
        break;
      case DTM.DOCUMENT_NODE :
        this.m_contentHandler.startDocument();
        break;
      case DTM.ELEMENT_NODE :
        DTM dtm = m_dtm;           
  
        for (int nsn = dtm.getFirstNamespaceNode(node, true); DTM.NULL != nsn;
             nsn = dtm.getNextNamespaceNode(node, nsn, true))
        {
          // String prefix = dtm.getPrefix(nsn);
          String prefix = dtm.getNodeNameX(nsn);
  
          this.m_contentHandler.startPrefixMapping(prefix, dtm.getNodeValue(nsn));
          
        }
  
        // System.out.println("m_dh.getNamespaceOfNode(node): "+m_dh.getNamespaceOfNode(node));
        // System.out.println("m_dh.getLocalNameOfNode(node): "+m_dh.getLocalNameOfNode(node));
        String ns = dtm.getNamespaceURI(node);
        if(null == ns)
          ns = "";
          
        // %OPT% !!
        org.xml.sax.helpers.AttributesImpl attrs = 
                              new org.xml.sax.helpers.AttributesImpl();
                
        for (int i = dtm.getFirstAttribute(node); 
             i != DTM.NULL; 
             i = dtm.getNextAttribute(i)) 
        {
          attrs.addAttribute(dtm.getNamespaceURI(i), 
                             dtm.getLocalName(i), 
                             dtm.getNodeName(i), 
                             "CDATA", 
                             dtm.getNodeValue(i));
        }
        
          
        this.m_contentHandler.startElement(ns,
                                           m_dtm.getLocalName(node),
                                           m_dtm.getNodeName(node),
                                           attrs);
        break;
      case DTM.PROCESSING_INSTRUCTION_NODE :
      {
        String name = m_dtm.getNodeName(node);
  
        // String data = pi.getData();
        if (name.equals("xslt-next-is-raw"))
        {
          nextIsRaw = true;
        }
        else
        {
          this.m_contentHandler.processingInstruction(name,
                                                      m_dtm.getNodeValue(node));
        }
      }
      break;
      case DTM.CDATA_SECTION_NODE :
      {
        boolean isLexH = (m_contentHandler instanceof LexicalHandler);
        LexicalHandler lh = isLexH
                            ? ((LexicalHandler) this.m_contentHandler) : null;
  
        if (isLexH)
        {
          lh.startCDATA();
        }
        
        dispatachChars(node);
  
        {
          if (isLexH)
          {
            lh.endCDATA();
          }
        }
      }
      break;
      case DTM.TEXT_NODE :
      {
        if (nextIsRaw)
        {
          nextIsRaw = false;
  
          m_contentHandler.processingInstruction(javax.xml.transform.Result.PI_DISABLE_OUTPUT_ESCAPING, "");
          dispatachChars(node);
          m_contentHandler.processingInstruction(javax.xml.transform.Result.PI_ENABLE_OUTPUT_ESCAPING, "");
        }
        else
        {
          dispatachChars(node);
        }
      }
      break;
      case DTM.ENTITY_REFERENCE_NODE :
      {
        if (m_contentHandler instanceof LexicalHandler)
        {
          ((LexicalHandler) this.m_contentHandler).startEntity(
            m_dtm.getNodeName(node));
        }
        else
        {
  
          // warning("Can not output entity to a pure SAX ContentHandler");
        }
      }
      break;
      default :
      }
    }
  
    /**
     * End processing of given node 
     *
     *
     * @param node Node we just finished processing
     *
     * @throws org.xml.sax.SAXException
     */
    protected void endNode(int node) throws org.xml.sax.SAXException
    {
  
      switch (m_dtm.getNodeType(node))
      {
      case DTM.DOCUMENT_NODE :
        this.m_contentHandler.endDocument();
        break;
      case DTM.ELEMENT_NODE :
        String ns = m_dtm.getNamespaceURI(node);
        if(null == ns)
          ns = "";
        this.m_contentHandler.endElement(ns,
                                           m_dtm.getLocalName(node),
                                           m_dtm.getNodeName(node));
  
        for (int nsn = m_dtm.getFirstNamespaceNode(node, true); DTM.NULL != nsn;
             nsn = m_dtm.getNextNamespaceNode(node, nsn, true))
        {
          // String prefix = m_dtm.getPrefix(nsn);
          String prefix = m_dtm.getNodeNameX(nsn);
  
          this.m_contentHandler.endPrefixMapping(prefix);
        }
        break;
      case DTM.CDATA_SECTION_NODE :
        break;
      case DTM.ENTITY_REFERENCE_NODE :
      {
        if (m_contentHandler instanceof LexicalHandler)
        {
          LexicalHandler lh = ((LexicalHandler) this.m_contentHandler);
  
          lh.endEntity(m_dtm.getNodeName(node));
        }
      }
      break;
      default :
      }
    }
  }  //TreeWalker
  
  