class Message {
    public final Calendar now = Calendar.getInstance();
    public Object ext = null;
    public SimpleDateFormat format = null;

    public SimpleDateFormat getFormat(String pattern) {<FILL_FUNCTION_BODY>}

    public SimpleDateFormat getFormat() {
        if (null == format) {
            format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        }
        return format;
    }

}

        if (null == format) {
            format = new SimpleDateFormat(pattern);
        } else {
            format.applyPattern(pattern);
        }
        return format;
    
<no_super_class>