examples/mutualExclusion/centralized/Coordinator.java

   1 /*
   2  * 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
   8 package mutualExclusion.centralized;
   9 import java.util.LinkedList;
  10
  11 import org.simgrid.msg.Host;
  12 import org.simgrid.msg.Msg;
  13 import org.simgrid.msg.MsgException;
  14 import org.simgrid.msg.Task;
  15 import org.simgrid.msg.Process;
  16
  17
  18 public class Coordinator extends Process  {
  19     public Coordinator(Host host, String name, String[]args) {
  20                 super(host,name,args);
  21     }
  22         LinkedList<RequestTask> waitingQueue=new LinkedList<RequestTask>();
  23         int CsToServe;
  24
  25         public void main(String[] args) throws MsgException {
  26                 CsToServe = Integer.parseInt(args[0]);
  27                 Task task;
  28                 while (CsToServe >0) {
  29                         task = Task.receive("coordinator");
  30                         if (task instanceof RequestTask) {
  31                                 RequestTask t = (RequestTask) task;
  32                                 if (waitingQueue.isEmpty()) {
  33                                    Msg.info("Got a request from "+t.from+". Queue empty: grant it");
  34                                         GrantTask tosend =  new GrantTask();
  35                                         tosend.send(t.from);
  36                                 } else {
  37                                         waitingQueue.addFirst(t);
  38                                 }
  39                         } else if (task instanceof ReleaseTask) {
  40                                 if (!waitingQueue.isEmpty()) {
  41                                         RequestTask req = waitingQueue.removeLast();
  42                                         GrantTask tosend = new GrantTask();
  43                                         tosend.send(req.from);
  44                                 }
  45                                 CsToServe--;
  46                                 if (waitingQueue.isEmpty() && CsToServe==0) {
  47                                         Msg.info("we should shutdown the simulation now");
  48                                 }
  49                         }
  50                 }
  51         }
  52 }