public class ProdCons {
	private Buffer buff = new Buffer();

	// Constructor
	public ProdCons() {
		Productor prod = new Productor();
		Consumidor cons = new Consumidor();
		
		for (int i = 0; i < 4; i++) {
			new Thread(prod).start();
		}
		for (int i = 0; i < 4; i++) {
			new Thread(cons).start();
		}
	}

	private class Buffer {
		private static final int DBUFF = 1;
		private int n = 0, in = 0, out = 0;
		private int[] b = new int[DBUFF];

		public synchronized void agregar(int v) throws InterruptedException {
			while (n == DBUFF) {
				wait();
			}
			b[in] = v;
			in = (in + 1) % DBUFF;
			n = n + 1;
			notifyAll();
		}

		public synchronized int sacar() throws InterruptedException {
			while (n == 0) {
				wait();
			}
			int v = b[out];
			out = (out + 1) % DBUFF;
			n = n - 1;
			notifyAll();
			return v;
		}
	}

	private class Productor implements Runnable {
		@Override
		public void run() {
			int i = 0;
			while (true) {
				try {
					buff.agregar(i++);
				}
				catch (Exception e) {
					e.printStackTrace();
				}
			}
		}
	}

	private class Consumidor implements Runnable {
		@Override
		public void run() {
			while (true) {
				try {
					System.out.println(Thread.currentThread().getId() + ": " + buff.sacar());
				}
				catch (Exception e) {
					e.printStackTrace();
				}
			}
		}
	}

	public static void main(String[] args) {
		new ProdCons();
	}
}