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/*
* Copyright (c) 2008 Paul C. Buetow, vs-sim@dev.buetow.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* All icons of the icons/ folder are under a Creative Commons
* Attribution-Noncommercial-Share Alike License a CC-by-nc-sa.
*
* The icon's homepage is http://code.google.com/p/ultimate-gnome/
*/
package protocols.implementations;
import core.VSMessage;
import protocols.VSAbstractProtocol;
/**
* The class VSExternalTimeSyncProtocol, an implementation of the external
* time synchronisation protocol.
*
* @author Paul C. Buetow
*/
public class VSExternalTimeSyncProtocol extends VSAbstractProtocol {
/** The serial version uid */
private static final long serialVersionUID = 1L;
/** The request time. */
private long requestTime;
/** The server is waiting for response, if true. */
private boolean waitingForResponse;
/**
* Instantiates a new external time sync protocol object.
*/
public VSExternalTimeSyncProtocol() {
super(VSAbstractProtocol.HAS_ON_CLIENT_START);
setClassname(getClass().toString());
}
/* (non-Javadoc)
* @see events.VSAbstractProtocol#onClientInit()
*/
public void onClientInit() {
}
/* (non-Javadoc)
* @see protocols.VSAbstractProtocol#onClientReset()
*/
public void onClientReset() {
}
/* (non-Javadoc)
* @see protocols.VSAbstractProtocol#onClientStart()
*/
public void onClientStart() {
requestTime = process.getTime();
waitingForResponse = true;
/* Multicast message to all processes */
VSMessage message = new VSMessage();
message.setBoolean("isClientRequest", true);
sendMessage(message);
}
/* (non-Javadoc)
* @see protocols.VSAbstractProtocol#onClientRecv(core.VSMessage)
*/
public void onClientRecv(VSMessage recvMessage) {
if (!recvMessage.getBoolean("isServerResponse"))
return;
if (waitingForResponse)
waitingForResponse = false;
else
return;
long recvTime = process.getTime();
long roundTripTime = recvTime - requestTime;
long serverTime = recvMessage.getLong("time");
long newTime = serverTime + (long) (roundTripTime / 2);
log("Server Zeit: " + serverTime + "; RTT: " + roundTripTime +
"; Alte Zeit: " + recvTime + "; Neue Zeit: " + newTime +
"; Offset: " + (newTime - recvTime));
process.setTime(newTime);
}
/* (non-Javadoc)
* @see protocols.VSAbstractProtocol#onClientSchedule()
*/
public void onClientSchedule() {
}
/* (non-Javadoc)
* @see events.VSAbstractProtocol#onServerInit()
*/
public void onServerInit() {
}
/* (non-Javadoc)
* @see protocols.VSAbstractProtocol#onServerReset()
*/
public void onServerReset() {
}
/* (non-Javadoc)
* @see protocols.VSAbstractProtocol#onServerRecv(core.VSMessage)
*/
public void onServerRecv(VSMessage recvMessage) {
if (!recvMessage.getBoolean("isClientRequest"))
return;
/* Multicast message to all processes */
VSMessage message = new VSMessage();
message.setLong("time", process.getTime());
message.setBoolean("isServerResponse", true);
sendMessage(message);
}
/* (non-Javadoc)
* @see protocols.VSAbstractProtocol#onServerSchedule()
*/
public void onServerSchedule() {
}
/* (non-Javadoc)
* @see protocols.VSAbstractProtocol#toString()
*/
public String toString() {
return super.toString();
}
}
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