// JAXP classes
import javax.xml.parsers.SAXParserFactory;
import javax.xml.parsers.SAXParser;

// SAX classes
import org.xml.sax.XMLReader;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/** Count the number of link elements in an XML document */ 
class SAXCountLinks {

  /** Source for RSS feed */
  //static String FEED_URL = "http://today.java.net/rss/21.rss";

  /** Initialize XMLReader and set up event handlers */
  static public void main(String args[]) {
    try {

String FEED_URL = args[0];

      // JAXP-style initialization of SAX parser
      SAXParserFactory saxFactory = SAXParserFactory.newInstance();
      XMLReader parser = saxFactory.newSAXParser().getXMLReader();

      // SAX-style processing of RSS document at FEED_URL
      parser.setContentHandler(new CountElementsHelper());
      parser.parse(FEED_URL);
    }
    catch (Exception e) {
      e.printStackTrace();
    }
    return;
  }

  /** Helper class containing SAX event handler methods */
  private static class CountElementsHelper extends DefaultHandler {

    /** Number of 'p' elements seen so far */
    int numElements;

    /** Constructor (allows for superclass initialization) */
    CountElementsHelper() {
      super();
    }

    /** Perform initialization for this instance */
    public void startDocument() throws SAXException {
      numElements = 0;
      return;
    }

    /** Process the start of an element */
    public void startElement(String namespaceURI, String localName,
                             String qName, Attributes atts)
        throws SAXException
    {
       if (qName.equals("link")) {
         numElements++;
       }
       return;
    }

    /** Done with document; output final count */
    public void endDocument() throws SAXException {
      System.out.println("Input document has " +
                         numElements +
                         " 'link' elements.");
      return;
    }
  }
}