simgrid-java/examples/bittorrent/Tracker.java

   1 /*
   2  * Copyright 2006-2012. The SimGrid Team. 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 import java.util.Iterator;
  10
  11 import org.simgrid.msg.Comm;
  12 import org.simgrid.msg.Host;
  13 import org.simgrid.msg.Process;
  14 import org.simgrid.msg.Msg;
  15 import org.simgrid.msg.MsgException;
  16 import org.simgrid.msg.Task;
  17
  18 import org.simgrid.msg.RngStream;
  19 /**
  20  * Tracker, handle requests from peers.
  21  */
  22 public class Tracker extends Process {
  23         protected RngStream stream;
  24         /**
  25          * Peers list
  26          */
  27         protected ArrayList<Integer> peersList;
  28         /**
  29          * End time for the simulation
  30          */
  31         protected double deadline;
  32         /**
  33          * Current comm received
  34          */
  35         protected Comm commReceived = null;
  36
  37         public Tracker(Host host, String name, String[]args) {
  38                 super(host,name,args);
  39         }
  40
  41         @Override
  42         public void main(String[] args) throws MsgException {
  43                 if (args.length != 1) {
  44                         Msg.info("Wrong number of arguments for the tracker.");
  45                         return;
  46                 }
  47                 //Build the RngStream object for randomness
  48                 stream = new RngStream("tracker");
  49                 //Retrieve the end time
  50                 deadline = Double.valueOf(args[0]);
  51                 //Building peers array
  52                 peersList = new ArrayList<Integer>();
  53
  54                 Msg.info("Tracker launched.");
  55                 while (Msg.getClock() < deadline) {
  56                         if (commReceived == null) {
  57                                 commReceived = Task.irecv(Common.TRACKER_MAILBOX);
  58                         }
  59                         try {
  60                                 if (commReceived.test()) {
  61                                         Task task = commReceived.getTask();
  62                                         if (task instanceof TrackerTask) {
  63                                                 TrackerTask tTask = (TrackerTask)task;
  64                                                 //Sending peers to the peer
  65                                                 int nbPeers = 0;
  66                                                 while (nbPeers < Common.MAXIMUM_PEERS && nbPeers < peersList.size()) {
  67                                                         int nextPeer;
  68                                                         do {
  69                                                                 nextPeer = stream.randInt(0, peersList.size() - 1);
  70                                                         } while (tTask.peers.contains(nextPeer));
  71                                                         tTask.peers.add(peersList.get(nextPeer));
  72                                                         nbPeers++;
  73                                                 }
  74                                                 //Adding the peer to our list
  75                                                 peersList.add(tTask.peerId);
  76                                                 tTask.type = TrackerTask.Type.ANSWER;
  77                                                 //Setting the interval
  78                                                 tTask.interval = Common.TRACKER_QUERY_INTERVAL;
  79                                                 //Sending the task back to the peer
  80                                                 tTask.dsend(tTask.mailbox);
  81                                         }
  82                                         commReceived = null;
  83                                 }
  84                                 else {
  85                                         waitFor(1);
  86                                 }
  87                         }
  88                         catch (MsgException e) {
  89                                 commReceived = null;
  90                         }
  91                 }
  92                 Msg.info("Tracker is leaving");
  93         }
  94
  95 }