// 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;
import org.xml.sax.InputSource;
import java.io.FileReader;

/** Print the content of the link elements in an XML document */ 
class SAXPrintLinks {

  /** Source for RSS feed */
//  static String FEED_FILE_NAME = "ExampleContentFeed.xml";

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

String FEED_FILE_NAME= args[0];

      // JAXP-style initialization of SAX parser
      SAXParserFactory saxFactory = SAXParserFactory.newInstance();
      saxFactory.setValidating(false);     // make default explicit
      saxFactory.setNamespaceAware(false); // make default explicit
      XMLReader parser = saxFactory.newSAXParser().getXMLReader();
      parser.setFeature("http://xml.org/sax/features/namespace-prefixes",
                        true);  // make default explicit

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

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

    /** Whether or not we are in a link element */
    boolean inLink = false;

    /** Character data collected for the current link element */
    StringBuffer charData;

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

    /** Process the start of an element */
    public void startElement(String namespaceURI, String localName,
                             String qName, Attributes atts)
        throws SAXException
    {
       if (qName.equals("link")) {
         inLink = true;
         charData = new StringBuffer();
       }
       return;
    }

    /** Process character data */
    public void characters(char chars[], int firstChar, int nChars) 
        throws SAXException
    {
      if (inLink) {
        charData.append(chars, firstChar, nChars);
      }
      return;
    }

    /** Process the end of an element.  If link, output
        collected character data. */
    public void endElement(String namespaceURI, String localName,
                           String qName)
        throws SAXException
    {
      if (qName.equals("link")) {
        System.out.println("Link data: " + charData.toString());
        inLink = false;
      }
      return;
    }
  }
}