/*
 * (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 java.util.Stack;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
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.DefaultHandler;

/**
 * A SAX application that builds a DOM tree from the SAX events, 
 * then traverses the tree backwards. 
 */

public class SaxToDom
  extends DefaultHandler 
{
  DocumentBuilderFactory dbf = null;
  DocumentBuilder docBuilder = null;
  Document root = null;
  boolean firstElementNotFoundYet = true;
  Stack elementStack = null;

  /** Prints the specified node, recursively. */
  public void printDOMTree(Node node) 
  {
    int type = node.getNodeType();
    switch (type)
    {
      // print the document element
      case Node.DOCUMENT_NODE: 
        {
          System.out.println("<?xml version=\"1.0\" ?>");
          printDOMTree(((Document)node).getDocumentElement());
          break;
        }

        // print element with attributes
      case Node.ELEMENT_NODE: 
        {
          System.out.print("<");
          System.out.print(node.getNodeName());

          if (node.hasAttributes())
          {          
            NamedNodeMap attrs = node.getAttributes();
            for (int i = 0; i < attrs.getLength(); i++)
              printDOMTree(attrs.item(i));
          }
          System.out.print(">");

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

          break;
        }

      // Print attribute nodes
      case Node.ATTRIBUTE_NODE:
        {
          System.out.print(" " + node.getNodeName() + "=\"");
          if (node.hasChildNodes())
          {
            NodeList children = node.getChildNodes();
            for (int i = 0; i < children.getLength(); i++)
              printDOMTree(children.item(i));
          }
          System.out.print("\"");
          break;
        }

        // handle entity reference nodes
      case Node.ENTITY_REFERENCE_NODE: 
        {
          System.out.print("&");
          System.out.print(node.getNodeName());
          System.out.print(";");
          break;
        }

        // print cdata sections
      case Node.CDATA_SECTION_NODE: 
        {
          System.out.print("<![CDATA[");
          System.out.print(node.getNodeValue());
          System.out.print("]]>");
          break;
        }

        // print text
      case Node.TEXT_NODE: 
        {
          System.out.print(node.getNodeValue());
          break;
        }

        // print processing instruction
      case Node.PROCESSING_INSTRUCTION_NODE: 
        {
          System.out.print("<?");
          System.out.print(node.getNodeName());
          String data = node.getNodeValue();
          {
            System.out.print(" ");
            System.out.print(data);
          }
          System.out.print("?>");
          break;
        }
    }

    if (type == Node.ELEMENT_NODE)
    {
      System.out.print("</");
      System.out.print(node.getNodeName());
      System.out.print('>');
    }
  } // printDOMTree(Node)

  public void parseAndPrint(String uri)
  {
    try
    { 
      dbf = DocumentBuilderFactory.newInstance();
      docBuilder = dbf.newDocumentBuilder();

      SAXParserFactory spf = SAXParserFactory.newInstance();
      SAXParser sp = spf.newSAXParser();
      sp.parse(uri, this);

      if (root != null)
        printDOMTree(root);
    }
    catch (ParserConfigurationException pce)
    {
      System.err.println("Parser configuration error : " + pce);
    }
    catch (Exception e)
    {
      System.err.println(e);
    }
  }
    
  /** Start document. */
  public void startDocument()
  {
    // If we knew the name of the root element, we could create
    // the Document object here.  We don't know the name of the
    // root, so we'll create it in startElement(), using a flag
    // to see if this is our first (aka root) element.
  } 

  /** Start element. */
  public void startElement(String namespaceURI, String localName, 
                           String rawName, Attributes attrs) 
  {
    if (firstElementNotFoundYet)
    {
      root = docBuilder.getDOMImplementation().
        createDocument(namespaceURI, rawName, null);
      Element docElement = root.getDocumentElement();
      if (attrs != null)
      {
        int len = attrs.getLength();
        for (int i = 0; i < len; i++)
          docElement.setAttribute(attrs.getQName(i), attrs.getValue(i));
      }

      elementStack = new Stack();
      elementStack.push(docElement);
      firstElementNotFoundYet = false;
    }
    else
    {
      Element currentElement = root.createElement(rawName);
      if (attrs != null)
      {
        int len = attrs.getLength();
        for (int i = 0; i < len; i++)
          currentElement.setAttribute(attrs.getQName(i), attrs.getValue(i));
      }
      elementStack.push(currentElement);
    }
  } // startElement

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

  /** Characters. */
  public void characters(char ch[], int start, int length) 
  {
    ((Element) elementStack.peek()).
      appendChild(root.createTextNode(new String(ch, start, length)));
  } // characters(char[],int,int);

  /** End element. */
  public void endElement(String namespaceURI, String localName, 
                         String rawName) 
  {
    if (elementStack.size() > 1)
    {
      Element currentElement = (Element) elementStack.pop();
      ((Element) elementStack.peek()).appendChild(currentElement);
    }
  } // endElement(String)

  /** End document. */
  public void endDocument() 
  {
    // Do nothing...
  } // endDocument()

  /** Processing instruction. */
  public void processingInstruction(String target, String data) 
  {
    ((Element) elementStack.peek()).
      appendChild(root.createProcessingInstruction(target, data));
  } // 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 SaxToDom uri");
      System.out.println("   where uri is the URI of your XML document.");
      System.out.println("   Sample:  java SaxToDom sonnet.xml");
      System.out.println("\nEchoes SAX events back to the console.");
      System.exit(1);
    }

    SaxToDom s2d = new SaxToDom();
    s2d.parseAndPrint(argv[0]);
  } // main(String[])
}