examples/java/mutualExclusion/Coordinator.java

   1 /* Copyright (c) 2012-2014. 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 mutualExclusion;
   8 import java.util.LinkedList;
   9
  10 import org.simgrid.msg.Host;
  11 import org.simgrid.msg.Msg;
  12 import org.simgrid.msg.MsgException;
  13 import org.simgrid.msg.Task;
  14 import org.simgrid.msg.Process;
  15
  16
  17 public class Coordinator extends Process  {
  18     public Coordinator(Host host, String name, String[]args) {
  19                 super(host,name,args);
  20     }
  21         LinkedList<RequestTask> waitingQueue=new LinkedList<RequestTask>();
  22         int CsToServe;
  23
  24         public void main(String[] args) throws MsgException {
  25                 CsToServe = Integer.parseInt(args[0]);
  26                 Task task;
  27                 while (CsToServe >0) {
  28                         task = Task.receive("coordinator");
  29                         if (task instanceof RequestTask) {
  30                                 RequestTask t = (RequestTask) task;
  31                                 if (waitingQueue.isEmpty()) {
  32                                    Msg.info("Got a request from "+t.from+". Queue empty: grant it");
  33                                         GrantTask tosend =  new GrantTask();
  34                                         tosend.send(t.from);
  35                                 } else {
  36                                         waitingQueue.addFirst(t);
  37                                 }
  38                         } else if (task instanceof ReleaseTask) {
  39                                 if (!waitingQueue.isEmpty()) {
  40                                         RequestTask req = waitingQueue.removeLast();
  41                                         GrantTask tosend = new GrantTask();
  42                                         tosend.send(req.from);
  43                                 }
  44                                 CsToServe--;
  45                                 if (waitingQueue.isEmpty() && CsToServe==0) {
  46                                         Msg.info("we should shutdown the simulation now");
  47                                 }
  48                         }
  49                 }
  50         }
  51 }