import java.awt.*;
import java.applet.Applet;
import java.awt.event.*;

public class Cafe extends Applet implements ActionListener  {

    private Button burger, fries, cola, cooked;
    private TextField newOrder =
        new TextField("awaiting order", 20);
    private TextArea queueDisplay =
        new TextArea("QUEUE\n", 5, 10, TextArea.SCROLLBARS_VERTICAL_ONLY);
    private TextField cooking =
        new TextField("nothing is cooking", 20);
    private Order order, complete;

    public void init() {
        burger = new Button("Burger");
        add (burger); 
        burger.addActionListener(this);
        fries = new Button("Fries");
        add (fries);
        fries.addActionListener(this);
        cola = new Button("Cola");
        add (cola);
        cola.addActionListener(this);

        add(newOrder);

        add(queueDisplay);

        add(cooking);

        cooked = new Button("Cooked");
        add (cooked);
        cooked.addActionListener(this);

        order = new Order();
        Queue queue = new Queue(queueDisplay);
        complete = new Order();

        Waiter waiter = new Waiter(newOrder, order, queue);
        waiter.start();

        Chef chef = new Chef(cooking, complete, queue);
        chef.start();
    }

    public void actionPerformed (ActionEvent event) {
        if (event.getSource() == burger)
            order.notifyEvent("burger");
        if (event.getSource() == fries)
            order.notifyEvent("fries");
        if (event.getSource() == cola)
            order.notifyEvent("cola");
        if (event.getSource() == cooked)
            complete.notifyEvent("cooked");
    }
}

class Waiter extends Thread {

    private Order order;
    private TextField display;
    private Queue queue;

    public Waiter(TextField display, Order order, Queue queue) {
        this.order = order;
        this.display = display;
        this.queue = queue;
    }

    public void run() {
        while (true) {
            String newOrder = order.waitForEvent();
            display.setText("new order: " + newOrder);
            try {
                Thread.sleep(5000);
            }
            catch (InterruptedException e) {
                System.err.println("Exception");
            }
            display.setText("awaiting order");
            queue.enter(newOrder);
        }
    }
}

class Order {

    private String order = "";

    public synchronized void notifyEvent(String newOrder) {
        order = newOrder;
        notify();
    }

    public synchronized String waitForEvent() {
        while (order.equals(""))
            try {
                wait();
            }
            catch (InterruptedException e) {
                System.err.println("Exception");
            }
        String newOrder = order;
        order = "";
        return newOrder;
    }
}

class Queue {
    private TextArea display;
    private String[] queue = new String[5];
    private int count = 0;

    public Queue(TextArea display) {
        this.display = display;
    }

    public synchronized void enter(String item) {
        queue[count] = item;
        count++;
        display();
        notify();
    }

    public synchronized String remove() {
        while (count == 0)
            try {
                wait();
            }
            catch (InterruptedException e) {
                System.err.println("Exception");
            }
        String item = queue[0];
        count--;
        for (int c = 0; c < count; c++)
            queue[c] = queue[c+1];
        display();
        return item;
    }

    private void display() {
        display.setText("QUEUE\n");
        for (int c = 0; c < count; c++)
            display.append(queue[c] + "\n");
    }
}

class Chef extends Thread{

    private TextField display;
    private Order complete;
    private Queue queue;

    public Chef(TextField display, Order complete, Queue queue) {
        this.display = display;
        this.complete = complete;
        this.queue = queue;
    }

    public void run() {
        display.setText("nothing is cooking");
        while (true) {
            String order = queue.remove();
            display.setText(order + " is cooking");
            String cookedInfo = complete.waitForEvent();
            display.setText("nothing is cooking");
        }
    }
}