8. JRadioButton using swing

import java.awt.*;
import java.awt.event.*;
import java.util.logging.Handler;
import javax.swing.*;

public class Gui extends JFrame{

    // Variables
    private JTextField tf;
    private Font pf;
    private Font bf;
    private Font itf;
    private Font bitf;
    private JRadioButton pb;
    private JRadioButton bb;
    private JRadioButton itb;
    private JRadioButton bitb;
    private ButtonGroup group;       // Establishes a relationship, so that only 1 is selected

    // Constructor
    public Gui(){

        // Basics
        super("Title");
        setLayout(new FlowLayout());

        // Text field
        tf = new JTextField("Hello world!", 20);
        add(tf);
        // Only 1 radio button is initialized to 'true' at the beginning
        pb = new JRadioButton("Plain", true);
        bb = new JRadioButton("Bold", false);
        itb = new JRadioButton("Italic", false);
        bitb = new JRadioButton("Bold + Italic", false);
        add(pb);
        add(itb);
        add(bb);
        add(bitb);
        // Group - This means that if I select 1, all THE OTHES WILL BE DESELECTED AUTOMATICALLY
        group = new ButtonGroup();
        group.add(pb);
        group.add(bb);
        group.add(itb);
        group.add(bitb);
        // Font
        pf = new Font("Seirf", Font.PLAIN, 14);
        bf = new Font("Seirf", Font.BOLD, 14);
        itf = new Font("Seirf", Font.ITALIC, 14);
        bitf = new Font("Seirf", Font.BOLD + Font.ITALIC, 14);
        // Initialize the default font
        tf.setFont(pf);

        // Listeners - Wait for event to happern, pass in font object to constructor
        pb.addItemListener(new HandlerClass(pf));
        bb.addItemListener(new HandlerClass(bf));
        itb.addItemListener(new HandlerClass(itf));
        bitb.addItemListener(new HandlerClass(bitf));
    }

    private class HandlerClass implements ItemListener{

        //  Variable
        private Font font;

        // Constructor
        public HandlerClass(Font f){
            font = f;
        }

        // Method
        public void itemStateChanged(ItemEvent event){
            tf.setFont(font);
        }

    }


    // Main
    public static void main(String[] args){
        Gui gui = new Gui();
        gui.setDefaultCloseOperation(EXIT_ON_CLOSE);
        gui.setSize(600, 600);
        gui.setVisible(true);
    }


}