src/java/simgrid/msg/Sem.java

   1 /*\r
   2  * $Id$\r
   3  *\r
   4  * Copyright 2006,2007 Martin Quinson, Malek Cherier           \r
   5  * All right reserved. \r
   6  *\r
   7  * This program is free software; you can redistribute \r
   8  * it and/or modify it under the terms of the license \r
   9  *(GNU LGPL) which comes with this package. \r
  10  */\r
  11  \r
  12 package simgrid.msg;\r
  13 \r
  14 public class Sem { \r
  15         \r
  16         /******************************************************************/\r
  17         /* Simple semaphore implementation, from Doug Lea (public domain) */\r
  18         /******************************************************************/\r
  19         private int permits_;\r
  20         \r
  21         public Sem(int i) {\r
  22                 permits_ = i;\r
  23         }\r
  24         \r
  25         public void acquire() throws InterruptedException {\r
  26                 \r
  27                 if (Thread.interrupted()) \r
  28                         throw new InterruptedException();\r
  29                 \r
  30                 synchronized(this) {\r
  31                 \r
  32                         try {\r
  33                                         while (permits_ <= 0) \r
  34                                                 wait();\r
  35                                         \r
  36                                         --permits_;\r
  37                         }\r
  38                         catch (InterruptedException ex) {\r
  39                                 notify();\r
  40                                 throw ex;\r
  41                         }\r
  42                 }\r
  43         }\r
  44 \r
  45         public synchronized void release() {\r
  46                 ++(this.permits_);\r
  47                 notify();\r
  48         }\r
  49 }\r