ping.java

High performance DB query

/*
 * @(#)$Id: Ping.java,v 1.6 2004/07/02 23:59:22 huebsch Exp $
 *
 * Copyright (c) 2001-2004 Regents of the University of California.
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached BERKELEY-LICENSE
 * file. If you do not find these files, copies can be found by writing to:
 * Computer Science Division, Database Group, Universite of California,
 * 617 Soda Hall #1776, Berkeley, CA 94720-1776. Attention: Berkeley License
 *
 * Copyright (c) 2003-2004 Intel Corporation. All rights reserved.
 *
 * This file is distributed under the terms in the attached INTEL-LICENSE file.
 * If you do not find these files, copies can be found by writing to:
 * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300,
 * Berkeley, CA, 94704.  Attention:  Intel License Inquiry.
 */


package util.network.ping;

import java.net.InetAddress;
import java.net.InetSocketAddress;
import services.LocalNode;
import services.network.Payload;
import services.network.udp.UDPClient;
import util.network.serialization.SerializationManager;
import util.timer.timeouts.TimeoutManager;
import util.timer.timeouts.TimeoutManagerClient;

/**
 * Class Ping
 *
 */
public class Ping implements UDPClient, TimeoutManagerClient {

    private int sequenceNumber;
    private int serverPort;
    private TimeoutManager timeoutManager;

    /**
     * Constructor Ping
     *
     * @param serverPort
     */
    public Ping(int serverPort) {
        this.serverPort = serverPort;
        sequenceNumber = 0;
        timeoutManager = new TimeoutManager();

        SerializationManager.registerClass("util.network.ping.EchoMessage");
        LocalNode.myUDPMessenger.listen(new Integer(serverPort), this);
    }

    /**
     * Method ping
     *
     * @param destination
     * @param timeout
     * @param additionalData
     * @param client
     */
    public void ping(InetSocketAddress destination, double timeout,
                     Payload additionalData, PingClient client) {
        double currentTime = LocalNode.myTimer.getCurrentTime();
        int curSequenceNumber = sequenceNumber++;
        EchoMessage message = EchoMessage.allocate(serverPort,
                                                   curSequenceNumber,
                                                   currentTime, additionalData);
        PingEntry entry = PingEntry.allocate(destination, client);

        timeoutManager.addAbsoluteTimeout(entry,
                                          new Integer(curSequenceNumber),
                                          currentTime + timeout, this);
        LocalNode.myUDPMessenger.send(destination, message);
    }

    private void processEchoMessage(InetAddress source, EchoMessage message) {
        message.convertToReply();
        LocalNode.myUDPMessenger.send(
            new InetSocketAddress(source, message.getIdentifier()), message);
    }

    private void processEchoReply(EchoMessage message) {
        double currentTime = LocalNode.myTimer.getCurrentTime();
        PingEntry entry = (PingEntry) timeoutManager.removeTimeout(
                              new Integer(message.getSequenceNumber()));

        // If entry is null, then the ping already expired
        if (entry != null) {
            entry.getClient().handlePingResponse(entry.getDestination(),
                                                 currentTime
                                                 - message.getSendTime(), true);
        }
    }

    /**
     * Method handleUDPNetwork
     *
     * @param source
     * @param data
     */
    public void handleUDPNetwork(InetSocketAddress source, Payload data) {
        if (data instanceof EchoMessage) {
            EchoMessage message = (EchoMessage) data;

            if (message.getType() == EchoMessage.ECHO_MESSAGE) {
                processEchoMessage(source.getAddress(), message);
            } else {
                processEchoReply(message);
            }
        }
    }

    /**
     * Method handleTimeout
     *
     * @param item
     * @param currentTime
     */
    public void handleTimeout(Object item, double currentTime) {
        PingEntry entry = (PingEntry) item;

        entry.getClient().handlePingResponse(entry.getDestination(), 0, false);
    }
}