FileDocCategorySizeDatePackage
TreeWalker.javaAPI DocJava SE 6 API14885Tue Jun 10 00:23:08 BST 2008com.sun.org.apache.xml.internal.serializer

TreeWalker

public final class TreeWalker extends Object
This class does a pre-order walk of the DOM tree, calling a ContentHandler interface as it goes. This class is a copy of the one in com.sun.org.apache.xml.internal.utils. It exists to cut the serializers dependancy on that package.
xsl.usage
internal

Fields Summary
private final ContentHandler
m_contentHandler
Local reference to a ContentHandler
private final SerializationHandler
m_Serializer
If m_contentHandler is a SerializationHandler, then this is a reference to the same object.
protected final com.sun.org.apache.xml.internal.serializer.utils.DOM2Helper
m_dh
DomHelper for this TreeWalker
private final LocatorImpl
m_locator
Locator object for this TreeWalker
boolean
nextIsRaw
Flag indicating whether following text to be processed is raw text
Constructors Summary
public TreeWalker(ContentHandler ch)

      this(ch,null);
public TreeWalker(ContentHandler contentHandler, String systemId)
Constructor.

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

      // Set the content handler
      m_contentHandler = contentHandler;
      if (m_contentHandler instanceof SerializationHandler) {
          m_Serializer = (SerializationHandler) m_contentHandler;
      }
      else
          m_Serializer = null;
          
      // Set the system ID, if it is given
      m_contentHandler.setDocumentLocator(m_locator);
      if (systemId != null)
          m_locator.setSystemId(systemId);
      else {
          try {
            // Bug see Bugzilla  26741
            m_locator.setSystemId(System.getProperty("user.dir") + File.separator + "dummy.xsl");
           }
           catch (SecurityException se) {// user.dir not accessible from applet             
           }
      }
          
      // Set the document locator  
                if (m_contentHandler != null)
                        m_contentHandler.setDocumentLocator(m_locator);
                try {
                   // Bug see Bugzilla  26741
                  m_locator.setSystemId(System.getProperty("user.dir") + File.separator + "dummy.xsl");
                } 
                catch (SecurityException se){// user.dir not accessible from applet
                  
    }
    m_dh = new DOM2Helper();
Methods Summary
private final voiddispatachChars(org.w3c.dom.Node node)
Optimized dispatch of characters.

  
         
      
      
  
    if(m_Serializer != null)
    {
      this.m_Serializer.characters(node);
    }
    else
    {
      String data = ((Text) node).getData();
      this.m_contentHandler.characters(data.toCharArray(), 0, data.length());
    }
protected voidendNode(org.w3c.dom.Node node)
End processing of given node

param
node Node we just finished processing
throws
org.xml.sax.SAXException


    switch (node.getNodeType())
    {
    case Node.DOCUMENT_NODE :
      break;
      
    case Node.ELEMENT_NODE :
      String ns = m_dh.getNamespaceOfNode(node);
      if(null == ns)
        ns = "";
      this.m_contentHandler.endElement(ns,
                                         m_dh.getLocalNameOfNode(node),
                                         node.getNodeName());

      if (m_Serializer == null) {
      // Don't bother with endPrefixMapping calls if the ContentHandler is a
      // SerializationHandler because SerializationHandler's ignore the
      // endPrefixMapping() calls anyways. . . .  This is an optimization.    
      Element elem_node = (Element) node;    
      NamedNodeMap atts = elem_node.getAttributes();
      int nAttrs = atts.getLength();

      // do the endPrefixMapping calls in reverse order 
      // of the startPrefixMapping calls
      for (int i = (nAttrs-1); 0 <= i; i--)
      {
        final Node attr = atts.item(i);
        final String attrName = attr.getNodeName();
        final int colon = attrName.indexOf(':");
        final String prefix;

        if (attrName.equals("xmlns") || attrName.startsWith("xmlns:"))
        {
          // Use "" instead of null, as Xerces likes "" for the 
          // name of the default namespace.  Fix attributed 
          // to "Steven Murray" <smurray@ebt.com>.
          if (colon < 0)
            prefix = "";
          else
            prefix = attrName.substring(colon + 1);

          this.m_contentHandler.endPrefixMapping(prefix);
        }
        else if (colon > 0) {
            prefix = attrName.substring(0, colon);
            this.m_contentHandler.endPrefixMapping(prefix);
        }
      }
      {
          String uri = elem_node.getNamespaceURI();
          if (uri != null) {
              String prefix = elem_node.getPrefix();
              if (prefix==null)
                prefix="";
              this.m_contentHandler.endPrefixMapping(prefix);              
          }
      }
      }
      break;
    case Node.CDATA_SECTION_NODE :
      break;
    case Node.ENTITY_REFERENCE_NODE :
    {
      EntityReference eref = (EntityReference) node;

      if (m_contentHandler instanceof LexicalHandler)
      {
        LexicalHandler lh = ((LexicalHandler) this.m_contentHandler);

        lh.endEntity(eref.getNodeName());
      }
    }
    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;
protected voidstartNode(org.w3c.dom.Node node)
Start processing given node

param
node Node to process
throws
org.xml.sax.SAXException


//   TODO: <REVIEW>
//    A Serializer implements ContentHandler, but not NodeConsumer
//    so drop this reference to NodeConsumer which would otherwise
//    pull in all sorts of things
//    if (m_contentHandler instanceof NodeConsumer)
//    {
//      ((NodeConsumer) m_contentHandler).setOriginatingNode(node);
//    }
//    TODO: </REVIEW>
                
                if (node instanceof Locator)
                {
                        Locator loc = (Locator)node;
                        m_locator.setColumnNumber(loc.getColumnNumber());
                        m_locator.setLineNumber(loc.getLineNumber());
                        m_locator.setPublicId(loc.getPublicId());
                        m_locator.setSystemId(loc.getSystemId());
                }
                else
                {
                        m_locator.setColumnNumber(0);
      m_locator.setLineNumber(0);
                }

    switch (node.getNodeType())
    {
    case Node.COMMENT_NODE :
    {
      String data = ((Comment) node).getData();

      if (m_contentHandler instanceof LexicalHandler)
      {
        LexicalHandler lh = ((LexicalHandler) this.m_contentHandler);

        lh.comment(data.toCharArray(), 0, data.length());
      }
    }
    break;
    case Node.DOCUMENT_FRAGMENT_NODE :

      // ??;
      break;
    case Node.DOCUMENT_NODE :
    
      break;
    case Node.ELEMENT_NODE :
      Element elem_node = (Element) node;
      {
          // Make sure the namespace node
          // for the element itself is declared
          // to the ContentHandler
          String uri = elem_node.getNamespaceURI();
          if (uri != null) {
              String prefix = elem_node.getPrefix();
              if (prefix==null)
                prefix="";
              this.m_contentHandler.startPrefixMapping(prefix,uri);              
          }
      }
      NamedNodeMap atts = elem_node.getAttributes();
      int nAttrs = atts.getLength();
      // System.out.println("TreeWalker#startNode: "+node.getNodeName());

      
      // Make sure the namespace node of
      // each attribute is declared to the ContentHandler
      for (int i = 0; i < nAttrs; i++)
      {
        final Node attr = atts.item(i);
        final String attrName = attr.getNodeName();
        final int colon = attrName.indexOf(':");
        final String prefix;

        // System.out.println("TreeWalker#startNode: attr["+i+"] = "+attrName+", "+attr.getNodeValue());
        if (attrName.equals("xmlns") || attrName.startsWith("xmlns:"))
        {
          // Use "" instead of null, as Xerces likes "" for the 
          // name of the default namespace.  Fix attributed 
          // to "Steven Murray" <smurray@ebt.com>.
          if (colon < 0)
            prefix = "";
          else
            prefix = attrName.substring(colon + 1);

          this.m_contentHandler.startPrefixMapping(prefix,
                                                   attr.getNodeValue());
        }
        else if (colon > 0) {
            prefix = attrName.substring(0,colon);
            String uri = attr.getNamespaceURI();
            if (uri != null)
                this.m_contentHandler.startPrefixMapping(prefix,uri);
        }        
      }

      String ns = m_dh.getNamespaceOfNode(node);
      if(null == ns)
        ns = "";
      this.m_contentHandler.startElement(ns,
                                         m_dh.getLocalNameOfNode(node),
                                         node.getNodeName(),
                                         new AttList(atts, m_dh));
      break;
    case Node.PROCESSING_INSTRUCTION_NODE :
    {
      ProcessingInstruction pi = (ProcessingInstruction) node;
      String name = pi.getNodeName();

      // String data = pi.getData();
      if (name.equals("xslt-next-is-raw"))
      {
        nextIsRaw = true;
      }
      else
      {
        this.m_contentHandler.processingInstruction(pi.getNodeName(),
                                                    pi.getData());
      }
    }
    break;
    case Node.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 Node.TEXT_NODE :
    {
      //String data = ((Text) node).getData();

      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 Node.ENTITY_REFERENCE_NODE :
    {
      EntityReference eref = (EntityReference) node;

      if (m_contentHandler instanceof LexicalHandler)
      {
        ((LexicalHandler) this.m_contentHandler).startEntity(
          eref.getNodeName());
      }
      else
      {

        // warning("Can not output entity to a pure SAX ContentHandler");
      }
    }
    break;
    default :
    }
public voidtraverse(org.w3c.dom.Node pos)
Perform a pre-order traversal non-recursive style. Note that TreeWalker assumes that the subtree is intended to represent a complete (though not necessarily well-formed) document and, during a traversal, startDocument and endDocument will always be issued to the SAX listener.

param
pos Node in the tree where to start traversal
throws
TransformerException


    this.m_contentHandler.startDocument();

    Node top = pos;

    while (null != pos)
    {
      startNode(pos);

      Node nextNode = pos.getFirstChild();

      while (null == nextNode)
      {
        endNode(pos);

        if (top.equals(pos))
          break;

        nextNode = pos.getNextSibling();

        if (null == nextNode)
        {
          pos = pos.getParentNode();

          if ((null == pos) || (top.equals(pos)))
          {
            if (null != pos)
              endNode(pos);

            nextNode = null;

            break;
          }
        }
      }

      pos = nextNode;
    }
    this.m_contentHandler.endDocument();
public voidtraverse(org.w3c.dom.Node pos, org.w3c.dom.Node top)
Perform a pre-order traversal non-recursive style. Note that TreeWalker assumes that the subtree is intended to represent a complete (though not necessarily well-formed) document and, during a traversal, startDocument and endDocument will always be issued to the SAX listener.

param
pos Node in the tree where to start traversal
param
top Node in the tree where to end traversal
throws
TransformerException


    this.m_contentHandler.startDocument();
    
    while (null != pos)
    {
      startNode(pos);

      Node nextNode = pos.getFirstChild();

      while (null == nextNode)
      {
        endNode(pos);

        if ((null != top) && top.equals(pos))
          break;

        nextNode = pos.getNextSibling();

        if (null == nextNode)
        {
          pos = pos.getParentNode();

          if ((null == pos) || ((null != top) && top.equals(pos)))
          {
            nextNode = null;

            break;
          }
        }
      }

      pos = nextNode;
    }
    this.m_contentHandler.endDocument();