void changePidRecord(List<Map> data, String fieldName, String content) {
        for (Map m : data) {
            if (m.get(Strings.PID_RECORD_JSON_KEY) != null
                    && m.get(Strings.PID_RECORD_JSON_KEY).equals(fieldName)) {
                if (content == null) {
                    data.remove(m);
                    return;
                } else {
                    m.put(Strings.PID_RECORD_JSON_DATA, content);
                    m.remove(Strings.PID_RECORD_JSON_HEX_DATA);
                    return;
                }
            }
        }
        // if we reached this line, add new field
        if (content != null) {
            Map m = new HashMap();
            m.put(Strings.PID_RECORD_JSON_KEY, fieldName);
            m.put(Strings.PID_RECORD_JSON_DATA, content);
            data.add(m);
        }
    }