Question

I’ve implemented a SAXparser in my application which has worked fine previously but i’m having problems with a new XML document.

This is my parser

public List<Article> getLatestArticles(String feedUrl) {
URL url = null;
    try {

        SAXParserFactory spf = SAXParserFactory.newInstance();
        SAXParser sp = spf.newSAXParser();
        XMLReader xr = sp.getXMLReader();

        url = new URL(feedUrl);

        xr.setContentHandler(this);
        xr.parse(new InputSource(url.openStream()));


    } catch (IOException e) {
        Log.e("RSS Handler IO", e.getMessage() + " >> " + e.toString());
    } catch (SAXException e) {
        Log.e("RSS Handler SAX", e.toString());
    } catch (ParserConfigurationException e) {
        Log.e("RSS Handler Parser Config", e.toString());
    }
    catch (java.lang.IllegalArgumentException e){
        Log.e("RSS Handler lang", e.getMessage() + " >> " + e.toString());
    }

    return articleList;
}

The parser starts off ok but then i get a java.lang.IllegalArgumentException error. I believe this may be due to an element with no value in my xml feed, it looks like this <Description/>.

Any suggestion on how to fix this would be much appreciated.

Answer 1

If </Description> is a self closing tag (i.e. it has not opening <Description> tag and no text value) then this syntax is perfectly correct.

It is hard to tell exactly what is causing the error without seeing the callback methods (e.g. startElement method) but there is one major gottcha that you can check

The SAX parse method throws an illegalArguementException if the InputStream is null. It might be worth checking the value coming into the SAX parser.

You can use the following code to check the input stream for nulls.

InputStreamReader reader = new InputStreamReader(url.openStream());

if (!reader.ready()) {
    System.out.println("error");
}