سلام تحلیل این کد چیه؟ مرتبش کردم

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Scanner;
import java.io.*;

public class NotepadExam extends JFrame implements ActionListener {//سلام این خط یعنی چی
    //taarif menuha va text
    private TextArea area = new TextArea("", 0, 0,
            TextArea.SCROLLBARS_VERTICAL_ONLY);
    private MenuBar menuBar = new MenuBar();
    private Menu file = new Menu();
    private MenuItem openFile = new MenuItem();
    private MenuItem newFile = new MenuItem();
    private MenuItem saveFile = new MenuItem();
    private MenuItem close = new MenuItem();

    public NotepadExam() {
        this.setSize(500, 300);
        this.setTitle("Java Notepad");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        this.area.setFont(new Font("Century Gothic", Font.BOLD, 12));
        this.getContentPane().setLayout(new BorderLayout());
        this.getContentPane().add(area);
        this.setMenuBar(this.menuBar);
        this.menuBar.add(this.file);
        this.file.setLabel("File");
        this.openFile.setLabel("Open");
        this.openFile.addActionListener(this);
        this.openFile.setShortcut(new MenuShortcut(KeyEvent.VK_O, false));
        this.file.add(this.openFile);
        this.newFile.setLabel("NewFile");
        this.newFile.addActionListener(this);
        this.newFile.setShortcut(new MenuShortcut(KeyEvent.VK_O, false));
        this.file.add(this.newFile);
        this.saveFile.setLabel("Save");
        this.saveFile.addActionListener(this);
        this.saveFile.setShortcut(new MenuShortcut(KeyEvent.VK_S, false));
        this.file.add(this.saveFile);
        this.close.setLabel("Close");
        this.close.setShortcut(new MenuShortcut(KeyEvent.VK_F4, false));
        this.close.addActionListener(this);
        this.file.add(this.close);
    }
    public void actionPerformed(ActionEvent e) {

        if (e.getSource() == this.close)
            this.dispose();

        else if (e.getSource() == this.openFile) {
JFileChooser open = new JFileChooser();
      int opt = open.showOpenDialog(this);//درون opt چی قرار داره

            if (opt == JFileChooser.APPROVE_OPTION) {
                this.area.setText("");
                try {

                    Scanner scan = new Scanner(new FileReader(open
                            .getSelectedFile().getPath()));
                    while (scan.hasNext())//این خط رو هم توضیح بدهید
                        this.area.append(scan.nextLine() + "\n");
                } catch (Exception ex) {

                    System.out.println(ex.getMessage());
                }
            }
        }

        else if (e.getSource() == this.saveFile) {
            JFileChooser save = new JFileChooser();
            int opt = save.showSaveDialog(this);

            if (opt == JFileChooser.APPROVE_OPTION) {//این خط چیکار میکنه
                try {

                    BufferedWriter out = new BufferedWriter(new FileWriter(save
                            .getSelectedFile().getPath()));
                    out.write(this.area.getText());
                    out.close();
                } catch (Exception ex) {

                    System.out.println(ex.getMessage());
                }
            }
        }
    }

    public static void main(String args[]) {
        NotepadExam app = new NotepadExam();
        app.setVisible(true);
    }
}