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
  38                                 wait();
  39                         }
  40                         catch (InterruptedException e) {}
  41                 }
  42                 nbObj++;
  43                 tampon[prem] = obj;
  44                 prem = (prem + 1) % taille;
  45                 //System.out.println(Thread.currentThread().getName() + " a depose " + (Integer)obj);
  46                 notifyAll();
  47         }
  48
  49
  50         public synchronized Object preleve() {
  51                 while(isEmpty()) {
  52                         try {
  53                                 System.out.println("Buffer is empty: " + Thread.currentThread().getName()
  54                                     + " is waiting, size: " + nbObj);
  55                                 wait();
  56                         }
  57                         catch (InterruptedException e) {}
  58                 }
  59                 Object outObj = null;
  60                 nbObj--;
  61                 outObj = tampon[der];
  62                 der = (der + 1) % taille;
  63                 //System.out.println(Thread.currentThread().getName() + " a preleve " + (Integer)outObj);
  64                 notifyAll();
  65                 return outObj;
  66         }
  67
  68 } // fin class BufferCirc