if(log.isInfoEnabled()) log.info("removing " + sender + " from received_msgs (not member anymore)");
if(log.isDebugEnabled()) log.debug("removing " + sender + " from received_msgs (not member anymore)");
    void adjustReceivers() {        Address sender;        NakReceiverWindow win;        // 1. Remove all senders in received_msgs that are not members anymore        for(Enumeration e=received_msgs.keys(); e.hasMoreElements();) {            sender=(Address)e.nextElement();            if(!members.contains(sender)) {                win=(NakReceiverWindow)received_msgs.get(sender);                win.reset();                if(log.isInfoEnabled())                    log.info("removing " + sender + " from received_msgs (not member anymore)");                received_msgs.remove(sender);            }        }        // 2. Add newly joined members to received_msgs (starting seqno=0)        for(int i=0; i < members.size(); i++) {            sender=(Address)members.elementAt(i);            if(!received_msgs.containsKey(sender)) {                win=new NakReceiverWindow(sender, this, 0, timer);                win.setRetransmitTimeouts(retransmit_timeout);                received_msgs.put(sender, win);            }        }    }