Java NetBeans用另一个调用ActionListener

Question

I am learning Java with GUI using JFrame, I would like to seek help regarding on how to call an ActionListener using an ActionListener. Here is some of my codes. The bottom part has the two action listeners and I added a simple comment for easy understanding.

package onlinedelivery;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class MainMenu extends JFrame {
    public JButton mainMenuButton;
    public JButton exitButton;
    public MainMenuButtonHandler mmHandler;
    public ExitButtonHandler exHandler;
    public static final int width = 400;
    public static final int heigth = 300;

public MainMenu() {
    Font bigFont = new Font("Arial",Font.BOLD,12);

    mainMenuButton = new JButton("Main Menu");
    mmHandler = new MainMenuButtonHandler();
    mainMenuButton.addActionListener(mmHandler);

    exitButton = new JButton("Exit");
    exHandler = new ExitButtonHandler();
    exitButton.addActionListener(exHandler);

    setTitle("Main Menu");

    Container pane = getContentPane();

    pane.setLayout(new GridLayout(5,2));

    pane.add(mainMenuButton);

    setSize(WIDTH,HEIGHT);
    setVisible(true);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
}

public class MainMenuButtonHandler implements ActionListener {
    @Override public void actionPerformed(ActionEvent e) {
        // ExitButtonHandler should be called here
        // When I click Main Menu Button Handler, ExitButtonHandler shall perform
    }
}

public class ExitButtonHandler implements ActionListener {      
    @Override public void actionPerformed(ActionEvent e) {
            System.exit(0);
        }
    }
}

Answer 1

If both Actions logic is the same you can define just one and use it for both menu and button.

If not you can extend one action from another

public class MainMenuButtonHandler extends ExitButtonHandler  {
    @Override public void actionPerformed(ActionEvent e) {
        // An additional logic here
        super.actionPerformed(e);
    }
}

Answer 2

You can use the doClick() method in JButton (inherited from AbstractButton)

With that alter the Handler Class of MainMenuButton like this:

public class MainMenuButtonHandler implements ActionListener {

    private JButton exitButton;

    public void setExitButton(JButton exitButton){
        this.exitButton = exitButton;
    }

    @Override public void actionPerformed(ActionEvent e) {
        //Do your work and invoke Click of exitButton
        this.exitButton.doClick();
    }
}

Also the MainMenu():

exitButton = new JButton("Exit");
exHandler = new ExitButtonHandler();
exitButton.addActionListener(exHandler);

mainMenuButton = new JButton("Main Menu");
mmHandler = new MainMenuButtonHandler();
mmHandler.setExitButton(exitButton) // newly added
mainMenuButton.addActionListener(mmHandler);