import java.util.ArrayList;

    public class StockMediator implements Mediator {

        private ArrayList<Colleague> colleagues;
        private ArrayList<Stock> stonks;

        public StockMediator() {
            colleagues = new ArrayList<>();
            stonks = new ArrayList<>();
        }

        public void addColleague(Colleague newColleague) {
            colleagues.add(newColleague);
        }

        public void addStock(Stock stock){
            stonks.add(stock);
        }

        public void stockChange() {
            for (Stock stock : stonks) {
                if (stock.getFreshness()) {
                    for (Colleague coll : colleagues) {
                        coll.getNewPrice(stock.getStockPrice(), stock.getstockName());
                    }
                    stock.setOld();
                }
            }

        }
    }


    public interface Mediator {

        public void stockChange();

        public void addColleague(Colleague colleague);

    }



    public abstract class Colleague {

        private Mediator mediator;

        public Colleague(Mediator newMediator) {
            mediator = newMediator;
            mediator.addColleague(this);
        }

        public void getNewPrice(int newPrice, String name) {
            System.out.println("New price for stock " + name + ": " + newPrice);
        }
    }




    public class ŻakStox extends Colleague {

        public ŻakStox(Mediator newMediator) {
            super(newMediator);

            System.out.println("ŻakStox signed up with the stockexchange\n");

        }

    }



    public class Stock {

        private String stockName = "";
        private int stockPrice = 0;
        private boolean ifNew = true;


        public Stock(String stockName, int stockPrice) {

            this.stockName = stockName;
            this.stockPrice = stockPrice;

        }

        public String getstockName() {
            return stockName;
        }

        public int getStockPrice() {
        return stockPrice;
        }

        public void setOld() {
            this.ifNew = false;
        }

        public boolean getFreshness() { return ifNew; }

        public void setNewPrice(int newPrice) {
            ifNew = true;
            stockPrice = newPrice;
        }
    }


import java.util.ArrayList;

public class Main {

    public static void main(String[] args) {
        StockMediator mediator = new StockMediator();

        ŻakStox żak = new ŻakStox(mediator);
        ŻakStox żak1 = new ŻakStox(mediator);
        Stock stock = new Stock("PWr", 666);
        Stock stock1 = new Stock("Zaliczcie mi mpis", 13);
        mediator.addStock(stock);
        mediator.addStock(stock1);

        mediator.stockChange();

        stock.setNewPrice(15);
        mediator.stockChange();

        stock.setNewPrice(737);
        stock1.setNewPrice(42);
        mediator.stockChange();
    }
}