TD1/exo3/BufferCirc.java

   1
   2
   3 /**
   4  * implementation du producteur consommateur avec un buffer circulaire
   5  */
   6 public class BufferCirc {
   7
   8         private Object[] tampon;
   9         private int taille;
  10         private int prem, der, nbObj;
  11
  12
  13         public BufferCirc (int t) {
  14                 taille = t;
  15                 tampon = new Object[taille];
  16                 prem = 0;
  17                 der = 0;
  18                 nbObj = 0;
  19         }
  20
  21
  22         public boolean isEmpty() {
  23                 return nbObj == 0;
  24         }
  25
  26
  27         public boolean isFull() {
  28                 return nbObj == taille;
  29         }
  30
  31
  32         public synchronized void depose(Object obj) {
  33                 while(isFull()) {
  34                         try {
  35                                 System.out.println("Buffer is full: " + Thread.currentThread().getName()
  36                                                                    + " is waiting, size: " + nbObj);
  37                                 wait();
  38                         }
  39                         catch (InterruptedException e) {}
  40                 }
  41                 nbObj++;
  42                 tampon[prem] = obj;
  43                 prem = (prem + 1) % taille;
  44                 //System.out.println(Thread.currentThread().getName() + " a depose " + (Integer)obj);
  45                 notifyAll();
  46         }
  47
  48
  49         public synchronized Object preleve() {
  50                 while(isEmpty()) {
  51                         try {
  52                                 System.out.println("Buffer is empty: " + Thread.currentThread().getName()
  53                                                                    + " is waiting, size: " + nbObj);
  54                                 wait();
  55                         }
  56                         catch (InterruptedException e) {}
  57                 }
  58                 Object outObj = null;
  59                 nbObj--;
  60                 outObj = tampon[der];
  61                 der = (der + 1) % taille;
  62                 //System.out.println(Thread.currentThread().getName() + " a preleve " + (Integer)outObj);
  63                 notifyAll();
  64                 return outObj;
  65         }
  66
  67 } // fin class BufferCirc