@Override
    public void characters(char[] ch, int start, int length)
            throws SAXException {
        if (depth == 0) {
            contentHandler.characters(ch, start, length);
        }
    }
@see org.xml.sax.helpers.XMLFilterImpl#characters(char[], int, int)
src/nu/validator/xml/NamespaceDroppingXMLReaderWrapper.java