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.xalan.xsltc.trax;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Hashtable;
  import java.util.List;
  import java.util.Stack;
  
  import org.apache.xalan.xsltc.dom.SAXImpl;
  import org.w3c.dom.NamedNodeMap;
  import org.w3c.dom.Node;
  import org.xml.sax.ContentHandler;
  import org.xml.sax.DTDHandler;
  import org.xml.sax.EntityResolver;
  import org.xml.sax.ErrorHandler;
  import org.xml.sax.InputSource;
  import org.xml.sax.Locator;
  import org.xml.sax.SAXException;
  import org.xml.sax.SAXNotRecognizedException;
  import org.xml.sax.SAXNotSupportedException;
  import org.xml.sax.XMLReader;
  import org.xml.sax.ext.LexicalHandler;
  import org.xml.sax.helpers.AttributesImpl;
  
  /**
   * @author G. Todd Miller 
   */
  public class DOM2SAX implements XMLReader, Locator {
  
      private final static String EMPTYSTRING = "";
      private static final String XMLNS_PREFIX = "xmlns";
  
      private Node _dom = null;
      private ContentHandler _sax = null;
      private LexicalHandler _lex = null;
      private SAXImpl _saxImpl = null;
      private Hashtable _nsPrefixes = new Hashtable();
  
      public DOM2SAX(Node root) {
  	_dom = root;
      }
  
      public ContentHandler getContentHandler() { 
  	return _sax;
      }
  
      public void setContentHandler(ContentHandler handler) throws 
  	NullPointerException 
      {
  	_sax = handler;
  	if (handler instanceof LexicalHandler) {
  	    _lex = (LexicalHandler) handler;
  	}
  	
  	if (handler instanceof SAXImpl) {
  	    _saxImpl = (SAXImpl)handler;
  	}
      }
  
      /**
       * Begin the scope of namespace prefix. Forward the event to the 
       * SAX handler only if the prefix is unknown or it is mapped to a 
       * different URI.
       */
      private boolean startPrefixMapping(String prefix, String uri) 
  	throws SAXException 
      {
  	boolean pushed = true;
  	Stack uriStack = (Stack) _nsPrefixes.get(prefix);
  
  	if (uriStack != null) {
  	    if (uriStack.isEmpty()) {
  		_sax.startPrefixMapping(prefix, uri);
  		uriStack.push(uri);
  	    }
  	    else {
  		final String lastUri = (String) uriStack.peek();
  		if (!lastUri.equals(uri)) {
  		    _sax.startPrefixMapping(prefix, uri);
  		    uriStack.push(uri);
  		}
  		else {
  		    pushed = false;
  		}
  	    }	
  	}
  	else {
  	    _sax.startPrefixMapping(prefix, uri);
  	    _nsPrefixes.put(prefix, uriStack = new Stack());
  	    uriStack.push(uri);
  	}
  	return pushed;
      }
  
      /*
       * End the scope of a name prefix by popping it from the stack and 
       * passing the event to the SAX Handler.
       */
      private void endPrefixMapping(String prefix) 
  	throws SAXException
      {
  	final Stack uriStack = (Stack) _nsPrefixes.get(prefix);
  
  	if (uriStack != null) {
  	    _sax.endPrefixMapping(prefix);
  	    uriStack.pop();
  	}
      }
  
      /**
       * If the DOM was created using a DOM 1.0 API, the local name may be 
       * null. If so, get the local name from the qualified name before 
       * generating the SAX event. 
       */
      private static String getLocalName(Node node) {
  	final String localName = node.getLocalName();
  
  	if (localName == null) {
  	    final String qname = node.getNodeName();
  	    final int col = qname.lastIndexOf(':');
  	    return (col > 0) ? qname.substring(col + 1) : qname;
  	}
  	return localName;
      }
  
      public void parse(InputSource unused) throws IOException, SAXException {
          parse(_dom);
      }
  
      public void parse() throws IOException, SAXException {
  	if (_dom != null) {
  	    boolean isIncomplete = 
  		(_dom.getNodeType() != org.w3c.dom.Node.DOCUMENT_NODE);
  
  	    if (isIncomplete) {
  		_sax.startDocument();
  		parse(_dom);
  		_sax.endDocument();
  	    }
  	    else {
  		parse(_dom);
  	    }
  	}
      }
  
      /**
       * Traverse the DOM and generate SAX events for a handler. A 
       * startElement() event passes all attributes, including namespace 
       * declarations. 
       */
      private void parse(Node node) throws IOException, SAXException {
          Node first = null;
   	if (node == null) return;
  
          switch (node.getNodeType()) {
  	case Node.ATTRIBUTE_NODE:         // handled by ELEMENT_NODE
  	case Node.DOCUMENT_FRAGMENT_NODE:
  	case Node.DOCUMENT_TYPE_NODE :
  	case Node.ENTITY_NODE :
  	case Node.ENTITY_REFERENCE_NODE:
  	case Node.NOTATION_NODE :
  	    // These node types are ignored!!!
  	    break;
  	case Node.CDATA_SECTION_NODE:
  	    final String cdata = node.getNodeValue();
  	    if (_lex != null) {
  		_lex.startCDATA();
  	        _sax.characters(cdata.toCharArray(), 0, cdata.length());
  		_lex.endCDATA();
   	    } 
  	    else {
  		// in the case where there is no lex handler, we still
  		// want the text of the cdate to make its way through.
  	        _sax.characters(cdata.toCharArray(), 0, cdata.length());
  	    }	
  	    break;
  
  	case Node.COMMENT_NODE:           // should be handled!!!
  	    if (_lex != null) {
  		final String value = node.getNodeValue();
  		_lex.comment(value.toCharArray(), 0, value.length());
  	    }
  	    break;
  	case Node.DOCUMENT_NODE:
  	    _sax.setDocumentLocator(this);
  
  	    _sax.startDocument();
  	    Node next = node.getFirstChild();
  	    while (next != null) {
  		parse(next);
  		next = next.getNextSibling();
  	    }
  	    _sax.endDocument();
  	    break;
  
  	case Node.ELEMENT_NODE:
  	    String prefix;
  	    List pushedPrefixes = new ArrayList();
  	    final AttributesImpl attrs = new AttributesImpl();
  	    final NamedNodeMap map = node.getAttributes();
  	    final int length = map.getLength();
  
  	    // Process all namespace declarations
  	    for (int i = 0; i < length; i++) {
  		final Node attr = map.item(i);
  		final String qnameAttr = attr.getNodeName();
  
  		// Ignore everything but NS declarations here
  		if (qnameAttr.startsWith(XMLNS_PREFIX)) {
  		    final String uriAttr = attr.getNodeValue();
  		    final int colon = qnameAttr.lastIndexOf(':');
  		    prefix = (colon > 0) ? qnameAttr.substring(colon + 1) : EMPTYSTRING;
  		    if (startPrefixMapping(prefix, uriAttr)) {
  			pushedPrefixes.add(prefix);
  		    }
  		}
  	    }
  
  	    // Process all other attributes
  	    for (int i = 0; i < length; i++) {
  		final Node attr = map.item(i);
  		final String qnameAttr = attr.getNodeName();
  
  		// Ignore NS declarations here
  		if (!qnameAttr.startsWith(XMLNS_PREFIX)) {
  		    final String uriAttr = attr.getNamespaceURI();
  		    final String localNameAttr = getLocalName(attr);
  
  		    // Uri may be implicitly declared
  		    if (uriAttr != null) {	
  			final int colon = qnameAttr.lastIndexOf(':');
  			prefix = (colon > 0) ? qnameAttr.substring(0, colon) : EMPTYSTRING;
  			if (startPrefixMapping(prefix, uriAttr)) {
  			    pushedPrefixes.add(prefix);
  			}
  		    }
  
  		    // Add attribute to list
  		    attrs.addAttribute(attr.getNamespaceURI(), getLocalName(attr), 
  			qnameAttr, "CDATA", attr.getNodeValue());
  		}
  	    }
  
  	    // Now process the element itself
  	    final String qname = node.getNodeName();
  	    final String uri = node.getNamespaceURI();
  	    final String localName = getLocalName(node);
  
  	    // Uri may be implicitly declared
  	    if (uri != null) {	
  		final int colon = qname.lastIndexOf(':');
  		prefix = (colon > 0) ? qname.substring(0, colon) : EMPTYSTRING;
  		if (startPrefixMapping(prefix, uri)) {
  		    pushedPrefixes.add(prefix);
  		}
  	    }
  
  	    // Generate SAX event to start element
  	    if (_saxImpl != null) {
  	        _saxImpl.startElement(uri, localName, qname, attrs, node);
  	    }
  	    else {
  	        _sax.startElement(uri, localName, qname, attrs);
  	    }
  
  	    // Traverse all child nodes of the element (if any)
  	    next = node.getFirstChild();
  	    while (next != null) {
  		parse(next);
  		next = next.getNextSibling();
  	    }
  
  	    // Generate SAX event to close element
  	    _sax.endElement(uri, localName, qname);
  
  	    // Generate endPrefixMapping() for all pushed prefixes
  	    final int nPushedPrefixes = pushedPrefixes.size();
  	    for (int i = 0; i < nPushedPrefixes; i++) {
  		endPrefixMapping((String) pushedPrefixes.get(i));
  	    }
  	    break;
  
  	case Node.PROCESSING_INSTRUCTION_NODE:
  	    _sax.processingInstruction(node.getNodeName(),
  				       node.getNodeValue());
  	    break;
  
  	case Node.TEXT_NODE:
  	    final String data = node.getNodeValue();
  	    _sax.characters(data.toCharArray(), 0, data.length());
  	    break;
  	}
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public DTDHandler getDTDHandler() { 
  	return null;
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public ErrorHandler getErrorHandler() {
  	return null;
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public boolean getFeature(String name) throws SAXNotRecognizedException,
  	SAXNotSupportedException
      {
  	return false;
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public void setFeature(String name, boolean value) throws 
  	SAXNotRecognizedException, SAXNotSupportedException 
      {
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public void parse(String sysId) throws IOException, SAXException {
  	throw new IOException("This method is not yet implemented.");
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public void setDTDHandler(DTDHandler handler) throws NullPointerException {
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public void setEntityResolver(EntityResolver resolver) throws 
  	NullPointerException 
      {
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public EntityResolver getEntityResolver() {
  	return null;
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public void setErrorHandler(ErrorHandler handler) throws 
  	NullPointerException
      {
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public void setProperty(String name, Object value) throws
  	SAXNotRecognizedException, SAXNotSupportedException {
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public Object getProperty(String name) throws SAXNotRecognizedException,
  	SAXNotSupportedException
      {
  	return null;
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public int getColumnNumber() { 
  	return 0; 
      }
      
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public int getLineNumber() { 
  	return 0; 
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public String getPublicId() { 
  	return null; 
      }
  
      /**
       * This class is only used internally so this method should never 
       * be called.
       */
      public String getSystemId() { 
  	return null; 
      }
  
      // Debugging 
      private String getNodeTypeFromCode(short code) {
  	String retval = null;
  	switch (code) {
  	case Node.ATTRIBUTE_NODE : 
  	    retval = "ATTRIBUTE_NODE"; break; 
  	case Node.CDATA_SECTION_NODE :
  	    retval = "CDATA_SECTION_NODE"; break; 
  	case Node.COMMENT_NODE :
  	    retval = "COMMENT_NODE"; break; 
  	case Node.DOCUMENT_FRAGMENT_NODE :
  	    retval = "DOCUMENT_FRAGMENT_NODE"; break; 
  	case Node.DOCUMENT_NODE :
  	    retval = "DOCUMENT_NODE"; break; 
  	case Node.DOCUMENT_TYPE_NODE :
  	    retval = "DOCUMENT_TYPE_NODE"; break; 
  	case Node.ELEMENT_NODE :
  	    retval = "ELEMENT_NODE"; break; 
  	case Node.ENTITY_NODE :
  	    retval = "ENTITY_NODE"; break; 
  	case Node.ENTITY_REFERENCE_NODE :
  	    retval = "ENTITY_REFERENCE_NODE"; break; 
  	case Node.NOTATION_NODE :
  	    retval = "NOTATION_NODE"; break; 
  	case Node.PROCESSING_INSTRUCTION_NODE :
  	    retval = "PROCESSING_INSTRUCTION_NODE"; break; 
  	case Node.TEXT_NODE:
  	    retval = "TEXT_NODE"; break; 
          }
  	return retval;
      }
  }
  