XWikiServletRequest.getParameterMap does nothing

public Map getParameterMap()
    {
        Map newMap = new HashMap();
        Map map = this.request.getParameterMap();
        Iterator it = map.keySet().iterator();
        while (it.hasNext()) {
            String key = (String) it.next();
            Object value = map.get(key);
            if (value instanceof String) {
                newMap.put(key, filterString((String) value));
            } else if (value instanceof String[]) {
                newMap.put(key, filterStringArray((String[]) value));
            } else {
                newMap.put(key, value);
            }
        }
        return map;
    }