Insert new element to an XML file using SAX Filter

Question

I have an XMl file that looks like:

  
    2
    

        

Answer 1

Your XMLFilter should delegate to another ContentHandler that serializes the document based on the sax events.

SAXTransformerFactory factory = (SAXTransformerFactory)TransformerFactory.newInstance();
TransformerHandler serializer = factory.newTransformerHandler();
Result result = new StreamResult(...);
serializer.setResult(result);

XMLFilterImpl filter = new MyFilter();
filter.setContentHandler(serializer);

XMLReader xmlreader = XMLReaderFactory.createXMLReader();
xmlreader.setFeature("http://xml.org/sax/features/namespaces", true);
xmlreader.setFeature("http://xml.org/sax/features/namespace-prefixes", true);
xmlreader.setContentHandler(filter);

xmlreader.parse(new InputSource(...));

Your callback should delegate to the super implementation, which forwards the events to the serializing ContentHandler.

public void startElement(String namespaceURI, String localName, String qName, Attributes atts) throws SAXException {
    super.startElement(namespaceURI, localName, qName, atts);
    ...
}

In your endElement callback you can check if your are at the final closing tag and add additional sax events.

public void endElement(String namespaceURI, String localName, String qName) throws SAXException {
    super.endElement(namespaceURI, localName, qName);
    if ("game".equals(localName)) {
        super.startElement("", "statistics", "statistics", new AttributesImpl());
        char[] chars = String.valueOf(num).toCharArray();
        super.characters(chars, 0, chars.length);
        super.endElement("", "statistics", "statistics");
    }
    ...
}