@Override
    public void startPrefixMapping(String prefix, String uri)
            throws SAXException {
        if (contentHandler == null) {
            return;
        }
        contentHandler.startPrefixMapping(prefix, uri);
    }
@param prefix
@param uri
@throws SAXException
@see org.xml.sax.ContentHandler#startPrefixMapping(java.lang.String,
     java.lang.String)
src/nu/validator/xml/AttributesPermutingXMLReaderWrapper.java