code: protected Boolean isUserAuthenticated(ActionBean bean, Method handler)
  	{
  		return bean.getContext().getRequest().getUserPrincipal() != null;
  	}
docs: Determine if the user is authenticated. The default implementation is to use {@code getUserPrincipal() != null}
  on the HttpServletRequest in the ActionBeanContext.
  
  @param bean    the current action bean; used for security decisions
  @param handler the current event handler; used for security decisions
  @return {@link Boolean#TRUE TRUE} if the user is authenticated, {@link Boolean#FALSE FALSE} if not, and {@code null} if undecided