examples/mutualExclusion/centralized/Coordinator.java

   1 /*
   2  * $Id$
   3  *
   4  * Copyright 2010. The SimGrid Team. All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the license (GNU LGPL) which comes with this package.
   8  */
   9
  10 package mutualExclusion.centralized;
  11 import java.util.LinkedList;
  12
  13 import org.simgrid.msg.Host;
  14 import org.simgrid.msg.Msg;
  15 import org.simgrid.msg.MsgException;
  16 import org.simgrid.msg.Task;
  17 import org.simgrid.msg.Process;
  18
  19
  20 public class Coordinator extends Process  {
  21         public Coordinator(Host host, String name, String[]args, double startTime, double killTime) {
  22                 super(host,name,args, startTime, killTime);
  23         }
  24         LinkedList<RequestTask> waitingQueue=new LinkedList<RequestTask>();
  25         int CsToServe;
  26
  27         public void main(String[] args) throws MsgException {
  28                 CsToServe = Integer.parseInt(args[0]);
  29                 Task task;
  30                 while (CsToServe >0) {
  31                         task = Task.receive("coordinator");
  32                         if (task instanceof RequestTask) {
  33                                 RequestTask t = (RequestTask) task;
  34                                 if (waitingQueue.isEmpty()) {
  35                                    Msg.info("Got a request from "+t.from+". Queue empty: grant it");
  36                                         GrantTask tosend =  new GrantTask();
  37                                         tosend.send(t.from);
  38                                 } else {
  39                                         waitingQueue.addFirst(t);
  40                                 }
  41                         } else if (task instanceof ReleaseTask) {
  42                                 if (!waitingQueue.isEmpty()) {
  43                                         RequestTask req = waitingQueue.removeLast();
  44                                         GrantTask tosend = new GrantTask();
  45                                         tosend.send(req.from);
  46                                 }
  47                                 CsToServe--;
  48                                 if (waitingQueue.isEmpty() && CsToServe==0) {
  49                                         Msg.info("we should shutdown the simulation now");
  50                                 }
  51                         }
  52                 }
  53         }
  54 }