/*
 * (C) Copyright IBM Corp. 2004.  All rights reserved.
 *
 * US Government Users Restricted Rights Use, duplication or
 * disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
 *
 * The program is provided "as is" without any warranty express or
 * implied, including the warranty of non-infringement and the implied
 * warranties of merchantibility and fitness for a particular purpose.
 * IBM will not be liable for any damages suffered by you as a result
 * of using the Program. In no event will IBM be liable for any
 * special, indirect or consequential damages or lost profits even if
 * IBM has been advised of the possibility of their occurrence. IBM
 * will not be liable for any third party claims against you.
 */

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.AttributesImpl;
import org.xml.sax.helpers.DefaultHandler;

public class DomToSax
  extends DefaultHandler 
{
  DocumentBuilderFactory dbf = null;
  DocumentBuilder db = null;

  public void parseAndPrint(String uri)
      throws SAXException
  {
    Document doc = null;

    try
    {
      dbf = DocumentBuilderFactory.newInstance();
      db = dbf.newDocumentBuilder();
      doc = db.parse(uri);
      if (doc != null)
        generateSAXEvents(doc, this);
    }
    catch (Exception e)
    {
      System.err.println("Sorry, an error occurred: " + e);
    }
  }

  /** Generates SAX events from the DOM tree. */
  public void generateSAXEvents(Node node, DefaultHandler dh) 
      throws SAXException
  {
    int type = node.getNodeType();
    switch (type)
    {
      // The document node corresponds to the startDocument() event
      case Node.DOCUMENT_NODE: 
        {
          dh.startDocument();
          generateSAXEvents(((Document)node).getDocumentElement(), dh);
          dh.endDocument();
          break;
        }

        // print element with attributes
      case Node.ELEMENT_NODE: 
        {
          AttributesImpl saxAttrs = new AttributesImpl();
          if (node.hasAttributes())
          {          
            NamedNodeMap attrs = node.getAttributes();
            for (int i = 0; i < attrs.getLength(); i++)
              saxAttrs.addAttribute(null, null, 
                                    attrs.item(i).getNodeName(),
                                    null, attrs.item(i).getNodeValue());
          }

          dh.startElement(null, null, node.getNodeName(), saxAttrs);

          if (node.hasChildNodes())
          {
            NodeList children = node.getChildNodes();
            for (int i = 0; i < children.getLength(); i++)
              generateSAXEvents(children.item(i), dh);
          }

          dh.endElement(null, null, node.getNodeName());
          break;
        }

        // print text
      case Node.TEXT_NODE: 
        {
          char[] chars = node.getNodeValue().toCharArray();
          dh.characters(chars, 0, chars.length);
          break;
        }

        // print processing instruction
      case Node.PROCESSING_INSTRUCTION_NODE: 
        {
          dh.processingInstruction(node.getNodeName(),
                                   node.getNodeValue());
          break;
        }
    }
  } // generateSAXEvents(Node, ContentHandler)
    
  /** Start document. */
  public void startDocument()
  {
    System.out.println("<?xml version=\"1.0\"?>");
  } // startDocument()

  /** Start element. */
  public void startElement(String namespaceURI, String localName, 
                           String rawName, Attributes attrs) 
  {
    System.out.print("<");
    System.out.print(rawName);
    if (attrs != null)
    {
      int len = attrs.getLength();
      for (int i = 0; i < len; i++)
      {
        System.out.print(" ");
        System.out.print(attrs.getQName(i));
        System.out.print("=\"");
        System.out.print(attrs.getValue(i));
        System.out.print("\"");
      }
    }
    System.out.print(">");
  } // startElement(String,AttributeList)

  /** Characters. */
  public void characters(char ch[], int start, int length) 
  {
    System.out.print(new String(ch, start, length));
  } // characters(char[],int,int);

  /** Ignorable whitespace. */
  public void ignorableWhitespace(char ch[], int start, int length) 
  {
    characters(ch, start, length);
  } // ignorableWhitespace(char[],int,int);

  /** End element. */
  public void endElement(String namespaceURI, String localName, 
                         String rawName) 
  {
    System.out.print("</");
    System.out.print(rawName);
    System.out.print(">");
  } // endElement(String)

  /** End document. */
  public void endDocument() 
  {
    // No need to do anything.
  } // endDocument()

  /** Processing instruction. */
  public void processingInstruction(String target, String data) 
  {
    System.out.print("<?");
    System.out.print(target);
    if (data != null && data.length() > 0)
    {
      System.out.print(' ');
      System.out.print(data);
    }
    System.out.print("?>");

  } // processingInstruction(String,String)

  //
  // ErrorHandler methods
  //

  /** Warning. */
  public void warning(SAXParseException ex) 
  {
    System.err.println("[Warning] "+
                       getLocationString(ex)+": "+
                       ex.getMessage());
  }

  /** Error. */
  public void error(SAXParseException ex) 
  {
    System.err.println("[Error] "+
                       getLocationString(ex)+": "+
                       ex.getMessage());
  }

  /** Fatal error. */
  public void fatalError(SAXParseException ex) 
    throws SAXException 
  {
    System.err.println("[Fatal Error] "+
                       getLocationString(ex)+": "+
                       ex.getMessage());
    throw ex;
  }

  /** Returns a string of the location. */
  private String getLocationString(SAXParseException ex) 
  {
    StringBuffer str = new StringBuffer();

    String systemId = ex.getSystemId();
    if (systemId != null)
    {
      int index = systemId.lastIndexOf('/');
      if (index != -1)
        systemId = systemId.substring(index + 1);
      str.append(systemId);
    }
    str.append(':');
    str.append(ex.getLineNumber());
    str.append(':');
    str.append(ex.getColumnNumber());

    return str.toString();
  } // getLocationString(SAXParseException):String

  /** Main program entry point. */
  public static void main(String argv[]) 
  {
    if (argv.length == 0 ||
        (argv.length == 1 && argv[0].equals("-help")))
    {
      System.out.println("\nUsage:  java DomToSax uri");
      System.out.println("   where uri is the URI of your XML document.");
      System.out.println("   Sample:  java DomToSax sonnet.xml");
      System.out.println("\nEchoes SAX events back to the console.");
      System.exit(1);
    }

    DomToSax d2s = new DomToSax();
    try
    {
      d2s.parseAndPrint(argv[0]);
    }
    catch (SAXException se) { }
  } // main(String[])
}