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