我不明白这个生产者/消费者的例子

Question

我在学校得到了这个例子来帮助我了解生产者/消费者，但我无法理解它。我花了一整天的时间，却没有任何进展。

谁能告诉我为什么它不能运行？

谢谢

public class CarPark {
   public static void main(String[] args) {

      CarParkControl carpark = new CarParkControl(4);

      Thread arrivals = new Thread(new Arrivals(carpark));

      Thread departures = new Thread(new Departures(carpark));

      arrivals.start();
      departures.start();

   }//main
}//CarPark



class Arrivals implements Runnable {

   CarParkControl carpark;
   Arrivals(CarParkControl c) {carpark = c;}

   public void run() {
      try {
         while(true) {
            carpark.arrive();
            Time.delay(RandomGenerator.integer(0,520));
         }
      } catch (InterruptedException e){}
   }
}



class Departures implements Runnable {

   CarParkControl carpark;
   Departures(CarParkControl c) {carpark = c;}

   public void run() {
      try {
         while(true) {
            carpark.depart();
            Time.delay(RandomGenerator.integer(0,520));
         }
      } catch (InterruptedException e){}
   }
}



class CarParkControl {

   protected int spaces;
   protected int capacity;

   CarParkControl(int capacity)
   {capacity = spaces = n;}

   synchronized void arrive() throws InterruptedException {
      while (spaces==0) wait();
      --spaces;
      notify();
   }//arrive

   synchronized void depart() throws InterruptedException {
      while (spaces==capacity) wait();
      ++spaces;
      notify();
   }//depart

}//CarParkControl

Answer 1

这一行无法编译

 capacity = spaces = n;

应该是

 this.capacity = spaces = capacity;

因为没有n

我建议你在尝试运行之前先编译程序。