examples/java/bittorrent/Tracker.java

   1 /*
   2  * Copyright (c) 2006-2013. The SimGrid Team.
   3  * All rights reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the license (GNU LGPL) which comes with this package.
   7  */
   8 package bittorrent;
   9 import java.util.ArrayList;
  10
  11 import org.simgrid.msg.Comm;
  12 import org.simgrid.msg.Host;
  13 import org.simgrid.msg.Msg;
  14 import org.simgrid.msg.MsgException;
  15 import org.simgrid.msg.Process;
  16 import org.simgrid.msg.RngStream;
  17 import org.simgrid.msg.Task;
  18 /**
  19  * Tracker, handle requests from peers.
  20  */
  21 public class Tracker extends Process {
  22         protected RngStream stream;
  23         /**
  24          * Peers list
  25          */
  26         protected ArrayList<Integer> peersList;
  27         /**
  28          * End time for the simulation
  29          */
  30         protected double deadline;
  31         /**
  32          * Current comm received
  33          */
  34         protected Comm commReceived = null;
  35
  36         public Tracker(Host host, String name, String[]args) {
  37                 super(host,name,args);
  38         }
  39
  40         @Override
  41         public void main(String[] args) throws MsgException {
  42                 if (args.length != 1) {
  43                         Msg.info("Wrong number of arguments for the tracker.");
  44                         return;
  45                 }
  46                 //Build the RngStream object for randomness
  47                 stream = new RngStream("tracker");
  48                 //Retrieve the end time
  49                 deadline = Double.valueOf(args[0]);
  50                 //Building peers array
  51                 peersList = new ArrayList<Integer>();
  52
  53                 Msg.info("Tracker launched.");
  54                 while (Msg.getClock() < deadline) {
  55                         if (commReceived == null) {
  56                                 commReceived = Task.irecv(Common.TRACKER_MAILBOX);
  57                         }
  58                         try {
  59                                 if (commReceived.test()) {
  60                                         Task task = commReceived.getTask();
  61                                         if (task instanceof TrackerTask) {
  62                                                 TrackerTask tTask = (TrackerTask)task;
  63                                                 //Sending peers to the peer
  64                                                 int nbPeers = 0;
  65                                                 while (nbPeers < Common.MAXIMUM_PEERS && nbPeers < peersList.size()) {
  66                                                         int nextPeer;
  67                                                         do {
  68                                                                 nextPeer = stream.randInt(0, peersList.size() - 1);
  69                                                         } while (tTask.peers.contains(nextPeer));
  70                                                         tTask.peers.add(peersList.get(nextPeer));
  71                                                         nbPeers++;
  72                                                 }
  73                                                 //Adding the peer to our list
  74                                                 peersList.add(tTask.peerId);
  75                                                 tTask.type = TrackerTask.Type.ANSWER;
  76                                                 //Setting the interval
  77                                                 tTask.interval = Common.TRACKER_QUERY_INTERVAL;
  78                                                 //Sending the task back to the peer
  79                                                 tTask.dsend(tTask.mailbox);
  80                                         }
  81                                         commReceived = null;
  82                                 }
  83                                 else {
  84                                         waitFor(1);
  85                                 }
  86                         }
  87                         catch (MsgException e) {
  88                                 commReceived = null;
  89                         }
  90                 }
  91                 Msg.info("Tracker is leaving");
  92         }
  93
  94 }