@Override
    public void onSignOut()
    {
        ServerUser u = currentClient.attachment();
        currentClient.close();

        if (u != null)
        {
            System.out.println( "SERVER: sign-out: " + u.name );

            userMap.remove( u.name );

            for (ServerUser otherUser : userMap.values())
            {
                otherUser.service.onUserSignOut( u.name );
            }
        }
        else
        {
            System.out.println( "SERVER: sign-out of unknown user" );
        }
    }