title: SessionDestroyedEvent getSecurityContexts() always empty
body: <p>I have a Web app using Spring 3.1.1 and Spring Security 3.1.0. I implemented an ApplicationListener that checks SessionDestroyedEvent(s) and should log the username and other data. However, the getSecurityContexts() always returns an empty Collection. I am authenticating against an LDAP server. I also checked the getSource() method and it returns session data which holds the Principal information. However, the objects are container specific implementations which differ and there is no interface/abstract class that I can use. My question is whether this is a bug in SpringSecurity, or can I do some additional configuration?</p>
  
  <p>Here is some relevant code:</p>
  
  <pre><code>@Service
  public class ApplicationSecurityListener implements ApplicationListener&lt;ApplicationEvent&gt;{
  
  @Override
    public void onApplicationEvent(ApplicationEvent event)
    {
             else if ( event instanceof SessionDestroyedEvent )
      {
          SessionDestroyedEvent sessinEvent = ( SessionDestroyedEvent ) event;
          //System.out.println ( "SessionDestroyedEvent:" + sessinEvent.getId() );
          //load session if it is not empty
          if(sessinEvent.getSecurityContexts() != null &amp;&amp; !sessinEvent.getSecurityContexts().isEmpty())
          {
              ...
              }}}}
  </code></pre>