import java.io.*;

// JAXP packages
import javax.xml.parsers.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;

/**
 * SaxPrint uses the Simple API for XML (SAX) to parse a given XML
 * document then print its element nodes.
 *
 * @author Thornton Rose
 * @version 1.0
 */
public class SaxPrint extends DefaultHandler {

   /**
    * Construct an instance of this class.
    */
   public SaxPrint() {
   }

   // DefaultHandler methods --------------------------------------------------

   /**
    * Called when the document has started.
    */
   public void startDocument() throws SAXException {
      System.out.println("BEGIN DOCUMENT");
   }


   /**
    * Called when the document has ended.
    */
   public void endDocument() throws SAXException {
      System.out.println("");
      System.out.println("END DOCUMENT");
   }

   /**
    * Called when an element has started.
    */
   public void startElement(String uri, String lName, String qName,
         Attributes attribs) throws SAXException {
      // Print node name.
      System.out.println("");
      System.out.println("   BEGIN " + qName);

      // Print attributes, if any.
      if (attribs.getLength() > 0) {
         for (int i = 0; i < attribs.getLength(); i ++) {
            System.out.println("      ." + attribs.getQName(i) + "=" +
               attribs.getValue(i));
         }
      }
   }

   /**
    * Called when an element has ended.
    */
   public void endElement(String uri, String lName, String qName)
         throws SAXException {
      System.out.println("   END " + qName);
   }

   /**
    * Called when element data has been parsed.
    */
   public void characters(char[] data, int start, int length)
         throws SAXException {

      StringBuffer buf = new StringBuffer(length);
      buf.append(data, start, length);

      if (buf.toString().trim().length() > 0) {
         System.out.println("      " + buf);
      }
   }

   //--------------------------------------------------------------------------

   /**
    * Print the given document.
    */
   private void print(File docFile) {
      try {
         // Get an instance of parser factory and configure it.
         SAXParserFactory factory = SAXParserFactory.newInstance();

         // Get a parser from the factory.
         SAXParser parser = factory.newSAXParser();

         // Parse the input file and print the elements.
         parser.parse(docFile, this);
      } catch(Exception ex) {
         System.out.println(ex);
      }
   }

   //--------------------------------------------------------------------------

   /**
    * Run the program.
    */
   public static void main(String[] args) {
      // If not enough args, print usage.
      if (args.length < 1) {
         System.out.println("Usage: SaxPrint file");
         System.exit(0);
      }

      // Get file name from command-line.
      File docFile = new File(args[0]);

      // Instantiate class and print.
      (new SaxPrint()).print(docFile);
   }

}