input/releases/qpid-jms-amqp-0-x-6.4.0/jms-amqp-0-8-book/JMS-Client-0-8-Appendix-JMS-Extensions-ConnectAttemptListener.html.in

<div class="docbook"><div class="navheader"><table summary="Navigation header" width="100%"><tr><th align="center" colspan="3">C.2.&#160;ConnectAttemptListener</th></tr><tr><td align="left" width="20%"><a accesskey="p" href="JMS-Client-0-8-Appendix-JMS-Extensions.html">Prev</a>&#160;</td><th align="center" width="60%">Appendix&#160;C.&#160;JMS Extensions</th><td align="right" width="20%">&#160;<a accesskey="n" href="JMS-Client-0-8-Appendix-JMS-Extensions-Queue.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="JMS-Client-0-8-Appendix-JMS-Extensions-ConnectAttemptListener"></a>C.2.&#160;ConnectAttemptListener</h2></div></div></div><p>An implementation of <span class="emphasis"><em>ConnectAttemptListener</em></span> can be set on <span class="emphasis"><em>AMQConnectionFactory</em></span>
        or <span class="emphasis"><em>PooledConnectionFactory</em></span> via <span class="emphasis"><em>#setConnectAttemptListener(ConnectAttemptListener)</em></span>
        in order to notify messaging application about every successful
        and unsuccessful connectivity attempt.
    </p><p>
        The failed attempt notification can be used as a trigger to rotate expired credentials,
        if those are set using <a class="link" href="JMS-Client-0-8-Appendix-JMS-Extensions.html#JMS-Client-0-8-Appendix-JMS-Extensions-Connection" title="C.1.&#160;Connection extensions">connection extensions</a>.
        The  implementation can examine the error code reported as part of JMSException, and, if the error code corresponds
        to authentication failure codes ("530" is reported by AMQP 0-8..0-91, "320" is reported by AMQP 0-10), the
        credentials could be swapped with new ones using the connection extension mechanism.
        See <a class="xref" href="JMS-Client-0-8-Appendix-JMS-Extensions.html#JMS-Client-0-8-Appendix-JMS-Extensions-Connection" title="C.1.&#160;Connection extensions">Section&#160;C.1, &#8220;Connection extensions&#8221;</a> for details.
    </p><p>The following implementation of <span class="emphasis"><em>ConnectAttemptListener</em></span> illustrate the idea.</p><div class="example"><a id="d0e3366"></a><p class="title"><strong>Example&#160;C.2.&#160;Rotate credentials on authentication failure</strong></p><div class="example-contents"><pre class="programlisting">
class CredentialsRotatingListener implements ConnectAttemptListener
{

    @Override
    public boolean connectAttemptFailed(final URI brokerURI, final JMSException e)
    {
        boolean reattempt = "530".equals(e.getErrorCode()) || "320".equals(e.getErrorCode());
        if (reattempt)
        {
            rotateCredentials(brokerURI);
        }
        return reattempt;
    }

    @Override
    public void connectAttemptSucceeded(final URI brokerURI)
    {
          credentialsRotatedSuccessfully(brokerURI);
    }

    private void rotateCredentials(inal URI brokerURI)
    {
        // credential rotating logic
    }

    private void credentialsRotatedSuccessfully(final URI brokerURI)
    {
         // notify that credentials have been rotated successfully
    }
}
      </pre></div></div><br class="example-break" /><p>
       The method <span class="emphasis"><em>connectAttemptFailed</em></span> can return true, if connection attempt needs to be repeated
       to the same broker immediately and without incrementing a failover re-try counter.
       Otherwise, the connection would be attempted as per failover settings.
   </p></div><div class="navfooter"><hr /><table summary="Navigation footer" width="100%"><tr><td align="left" width="40%"><a accesskey="p" href="JMS-Client-0-8-Appendix-JMS-Extensions.html">Prev</a>&#160;</td><td align="center" width="20%"><a accesskey="u" href="JMS-Client-0-8-Appendix-JMS-Extensions.html">Up</a></td><td align="right" width="40%">&#160;<a accesskey="n" href="JMS-Client-0-8-Appendix-JMS-Extensions-Queue.html">Next</a></td></tr><tr><td align="left" valign="top" width="40%">Appendix&#160;C.&#160;JMS Extensions&#160;</td><td align="center" width="20%"><a accesskey="h" href="JMS-Client-Book.html">Home</a></td><td align="right" valign="top" width="40%">&#160;C.3.&#160;Queue Management</td></tr></table></div></div>