Current admin user name from plugin

I am trying to modify the monitor plugin to have more access restrictions for certain users. Is there a way to access the current username logged into the admin console from the plugin? Specifically I'm hoping to use the user name in the ConversationUtil class and the ConversationPDFServlet. From the ConversationPDFServlet I have already tried request.getUserPrincipal() as well as request.getRemoteUser() both of which return null.