public class Main
{
    public static void main(String args[])
    {
        // creating buffer queue
        Queue q = new Queue();

        for(int i=0; i < 5; i++)
        new Consumer(q , i);

        for(int i=0; i < 4; i++)
        new Producer(q , i);
    }
}

public class Producer implements Runnable
{
    Queue q;
    private int id ;
    Producer(Queue q, int id) {
        this.q = q;
        this.id=id;
        new Thread(this, "Producer").start();
    }

    public void run() {
        for(int i=0; i < 50; i++)
            // producer put items
            q.put(id ,i);
    }
}

public class Consumer implements Runnable
{
    Queue q;
    private int id;
    Consumer(Queue q, int id ){
        this.q = q;
        this.id=id ;
        new Thread(this, "Consumer").start();
    }

    public void run()
    {
        for(int i=0; i < 50; i++)
            // consumer get items
            q.get(id) ;
    }
}


import java.util.Random;
import java.util.concurrent.Semaphore;




public class Queue
{
    static Random r= new Random();
    // an item
    int item;
    String data ;

    // semCon initialized with 0 permits
    // to ensure put() executes first
    static Semaphore semCon = new Semaphore(0);

    static Semaphore semProd = new Semaphore(1);

    // to get an item from buffer
    void get(int id)
    {

        String data2 ;
        try {
            losoweOpóźnienie2();
            // Before consumer can consume an item,
            // it must acquire a permit from semCon
            semCon.acquire();
        }
        catch(InterruptedException e) {
            System.out.println("InterruptedException caught");
        }

        // consumer consuming an item
        data2="[C-" + id + "," + item + "]"    ;
        System.out.println(data2 + " >> Dana= " + data);

        // After consumer consumes the item,
        // it releases semProd to notify producer
        semProd.release();
    }

    // to put an item in buffer
    void put(int id, int item)
    {

        try {
            losoweOpóźnienie1();
            // Before producer can produce an item,
            // it must acquire a permit from semProd
            semProd.acquire();
        } catch(InterruptedException e) {
            System.out.println("InterruptedException caught");
        }

        // producer producing an item
        this.item = item;
        data= "[P-" + id + "," + item + "," + r.nextInt(100) + "]";

        // After producer produces the item,
        // it releases semCon to notify consumer
        semCon.release();
    }
    private static void losoweOpóźnienie1() throws InterruptedException {
        Thread.sleep(r.nextInt(10-1));
    }
    private static void losoweOpóźnienie2() throws InterruptedException {
        Thread.sleep(r.nextInt(12-2));
    }