examples/java/bittorrent/Tracker.java

   1 /* Copyright (c) 2006-2014. The SimGrid Team.
   2  * All rights reserved.                                                     */
   3
   4 /* This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the license (GNU LGPL) which comes with this package. */
   6
   7 package bittorrent;
   8 import java.util.ArrayList;
   9
  10 import org.simgrid.msg.Comm;
  11 import org.simgrid.msg.Host;
  12 import org.simgrid.msg.Msg;
  13 import org.simgrid.msg.MsgException;
  14 import org.simgrid.msg.Process;
  15 import org.simgrid.msg.RngStream;
  16 import org.simgrid.msg.Task;
  17 /**
  18  * Tracker, handle requests from peers.
  19  */
  20 public class Tracker extends Process {
  21         protected RngStream stream;
  22         /**
  23          * Peers list
  24          */
  25         protected ArrayList<Integer> peersList;
  26         /**
  27          * End time for the simulation
  28          */
  29         protected double deadline;
  30         /**
  31          * Current comm received
  32          */
  33         protected Comm commReceived = null;
  34
  35         public Tracker(Host host, String name, String[]args) {
  36                 super(host,name,args);
  37         }
  38
  39         @Override
  40         public void main(String[] args) throws MsgException {
  41                 if (args.length != 1) {
  42                         Msg.info("Wrong number of arguments for the tracker.");
  43                         return;
  44                 }
  45                 //Build the RngStream object for randomness
  46                 stream = new RngStream("tracker");
  47                 //Retrieve the end time
  48                 deadline = Double.valueOf(args[0]);
  49                 //Building peers array
  50                 peersList = new ArrayList<Integer>();
  51
  52                 Msg.info("Tracker launched.");
  53                 while (Msg.getClock() < deadline) {
  54                         if (commReceived == null) {
  55                                 commReceived = Task.irecv(Common.TRACKER_MAILBOX);
  56                         }
  57                         try {
  58                                 if (commReceived.test()) {
  59                                         Task task = commReceived.getTask();
  60                                         if (task instanceof TrackerTask) {
  61                                                 TrackerTask tTask = (TrackerTask)task;
  62                                                 //Sending peers to the peer
  63                                                 int nbPeers = 0;
  64                                                 while (nbPeers < Common.MAXIMUM_PEERS && nbPeers < peersList.size()) {
  65                                                         int nextPeer;
  66                                                         do {
  67                                                                 nextPeer = stream.randInt(0, peersList.size() - 1);
  68                                                         } while (tTask.peers.contains(nextPeer));
  69                                                         tTask.peers.add(peersList.get(nextPeer));
  70                                                         nbPeers++;
  71                                                 }
  72                                                 //Adding the peer to our list
  73                                                 peersList.add(tTask.peerId);
  74                                                 tTask.type = TrackerTask.Type.ANSWER;
  75                                                 //Setting the interval
  76                                                 tTask.interval = Common.TRACKER_QUERY_INTERVAL;
  77                                                 //Sending the task back to the peer
  78                                                 tTask.dsend(tTask.mailbox);
  79                                         }
  80                                         commReceived = null;
  81                                 }
  82                                 else {
  83                                         waitFor(1);
  84                                 }
  85                         }
  86                         catch (MsgException e) {
  87                                 commReceived = null;
  88                         }
  89                 }
  90                 Msg.info("Tracker is leaving");
  91         }
  92
  93 }