void error ();


    /**
     * 
     * @return the message timeout
     */
    Long getExpiration ();


    /**
     * 
     * @param exp
     *            message timeout
     */
    void setExpiration ( Long exp );


    /**
     * 
     */
    public void reset ();


    /**
     * 
     * @return an exception linked to an error
     */