// PK.java

class Producer extends Thread {
	private Buffer _buf;

	public Producer(Buffer b) {
		_buf = b;
	}

	public void run() {
	  for (int i = 0; i < 100; ++i) {
		try { Thread.sleep((int)(50*Math.random())); } 
			catch(Exception e) {}
		_buf.put(i);
	  }
	}
}
		
class Consumer extends Thread {
	private Buffer _buf;

	public Consumer(Buffer b) {
		_buf = b;
	}

	public void run() {
	  for (int i = 0; i < 100; ++i) {
		try { Thread.sleep((int)(10*Math.random())); } 
			catch(Exception e) {}
		_buf.get();
	  }
	}
}
		
class Buffer {
	private int _buf[];
	private int _inbuf = 0; // ile elementow aktualnie w buforze
	private int _size;	// rozmiar bufora


	public Buffer(int size) {
		_buf = new int[size];
		_size = size;
	} 

	public boolean isFull() { return (_inbuf == _size); }
	public boolean isEmpty() { return (_inbuf == 0); }

	public synchronized void put(int i) {
		while(isFull()) { // 'condition wait'
	  		try { wait(); } catch (InterruptedException e) { }
		}
		_buf[_inbuf++] = i;
		System.out.println("P --> " + i);

		if (_inbuf == 1) { // produkcja do pustego bufora
			notify();
		}
	}

	public synchronized int get() {
		while(isEmpty()) { // 'condition wait'
			try { wait(); } catch (InterruptedException e) { }
		}

		int i = _buf[0];

		// 'dosuniecie' bufora do lewej
		for (int j = 0; j < _inbuf-1; ++j) {
			_buf[j] = _buf[j + 1];
		}
		--_inbuf;

		System.out.println("\tK --> " + i);

		if (_inbuf == _size-1) { // konsumpcja z pelnego bufora
			notify();
		}
		return i;
	}
}

public class PK {
  public static void main(String[] args) {
	Buffer b = new Buffer(10);
	Producer p = new Producer(b);
	Consumer c = new Consumer(b);

	p.start();
	c.start();
  }
}