title: liferay portlet: how to use autologin (alternatives also welcome)
body: <p>I'm using an external token service to validate my users and they then get redirected to the portal (portal url + some get parameters).<br>
  Now I would like to log these users in the portal.
  Since the external authentication service is outside of my control I can't just tie it in with the portal login. And since I can't decrypt the portal user account password I can't just create an <code>ext-plugin</code> and log in through that.</p>
  
  <p>So I searched a bit and stumbled upon the fact that liferay has an autologin.<br>
  Now I was wondering:</p>
  
  <ol>
  <li>can I just use this in a normal portlet, or does it also need to be in ext (still don't know how to exactly do that)</li>
  <li>which session variables/cookies do I need to make?</li>
  <li>does anyone have a code snippet/tutorial since I have yet to find a complete one.</li>
  <li>how feasible is this when keeping future versions of liferay in mind?</li>
  </ol>