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DTMTreeWalker.javaAPI DocJava SE 5 API10703Fri Aug 26 14:56:00 BST 2005com.sun.org.apache.xml.internal.dtm.ref

DTMTreeWalker

public class DTMTreeWalker extends Object
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

Fields Summary
private ContentHandler
m_contentHandler
Local reference to a ContentHandler
protected DTM
m_dtm
DomHelper for this TreeWalker
boolean
nextIsRaw
Flag indicating whether following text to be processed is raw text
Constructors Summary
public DTMTreeWalker()
Constructor.

param
contentHandler The implemention of the contentHandler operation (toXMLString, digest, ...)
public DTMTreeWalker(ContentHandler contentHandler, DTM dtm)
Constructor.

param
contentHandler The implemention of the contentHandler operation (toXMLString, digest, ...)

    this.m_contentHandler = contentHandler;
    m_dtm = dtm;
Methods Summary
private final voiddispatachChars(int node)
Optimized dispatch of characters.

  
         
      
      
  
    m_dtm.dispatchCharactersEvents(node, m_contentHandler, false);
protected voidendNode(int node)
End processing of given node

param
node Node we just finished processing
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 :
    }
public org.xml.sax.ContentHandlergetcontentHandler()
Get the ContentHandler used for the tree walk.

return
the ContentHandler used for the tree walk

    return m_contentHandler;
public voidsetDTM(com.sun.org.apache.xml.internal.dtm.DTM dtm)
Set the DTM to be traversed.

param
dtm The Document Table Model to be used.

  
                     
     
  
    m_dtm = dtm;
public voidsetcontentHandler(org.xml.sax.ContentHandler ch)
Set the ContentHandler used for the tree walk.

param
ch the ContentHandler to be the result of the tree walk.

    m_contentHandler = ch;
protected voidstartNode(int node)
Start processing given node

param
node Node to process
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 :
    }
public voidtraverse(int pos)
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

    // %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;
    }
public voidtraverse(int pos, int top)
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

    // %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;
    }