Parsing an xml file

5 Feb 2007 04:05:59 -0800
Hello, there. I have written a class Publication that represents,
let's say a book, and i want to read an xml file that contains info
about a publication and store the (attribute, value) to the above
class. When i run that simple application, terminates unexpectedly
without a single exception and without printing anything. I have a
suspicion about the line
sax.parse(input, this); in the readPublication method. Shouldn't i
use "this" as the second argument of parse? Should i create another
class that extends DefaultHandler and call parse as sax.parse(input,
new myClass())? But, then, how could i have access to the Hashtable
that stores (attribute, values)? Thanks a lot for your help.
The code is as follows:

public class Publication extends DefaultHandler implements
Serializable {

    Hashtable attributes;

     * for example book, paper, article
    String category;

     * the filename of that publication
    String filename;

     * the first tag should define the category
    boolean isFirstTag;

     * these are the currrent values of the read (attribute, value)
    String curtag;
    String curvalue;

    public Publication(String xmlfile, String originalFile) {
        attributes = new Hashtable();
        isFirstTag = true;
        filename = originalFile;

    public String getFilename() {
        return filename;

    public void readPublication(String filename) {

    File input = new File(filename);
        SAXParserFactory factory = SAXParserFactory.newInstance();
        try {
            SAXParser sax = factory.newSAXParser();

            sax.parse(input, this);

        } catch (ParserConfigurationException pce) {
            System.out.println("Could not create that parser.");
        } catch (SAXException se) {
            System.out.println("Problem with the SAX parser.");
        } catch (IOException ioe) {
            System.out.println("Error reading file.");

    public void startElement(String uri, String localName, String qName,
Attributes attributes) {
        if (isFirstTag) {
           isFirstTag = false;
           category = qName;
        } else
           curtag = qName;

    public void characters(char[] ch, int start, int length) {
        curvalue = new String(ch, start, length);

    public void endElement(String uri, String localName, String qName) {
        if (!qName.equals(category))
           attributes.put(curtag, curvalue);
        else {
           System.out.println("I' ve just read a new publication:");
           Set tags = attributes.keySet();
           Iterator it = tags.iterator();
           while (it.hasNext()) {
         String attr = (String);
         String value = (String) attributes.get(attr);
         System.out.println(attr + value);

    public static void main(String arguments[]) {

        Publication pub = new Publication("pub1.librml", "pub1.pdf");

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