// Project: Swing
// Module: listener
// Source code file MyFrame.java

// A listener is added to the three buttons,
// which can report which button was clicked. The event handler
// then goes back to the button and obtain the
// caption from the clicked button.

import java.awt.event.*;
import javax.swing.*;
public class MyFrame extends JFrame {

    // Declare and instantiate controls.
    private JButton buttonA =
            new JButton("Button A");
    private JButton buttonB =
            new JButton("Button B");
    private JButton buttonC =
            new JButton("Button C");
    private JTextArea textArea =
            new JTextArea( );
    private JPanel contentPanel =
            new JPanel( );

    // The main method creates the frame.
    public static void main(String[] args) {
        new MyFrame( );
    }

    public MyFrame( ) {

        // Set text in title bar.
        super("SwingControls Example");

        // Don't use layout manager
        contentPanel.setLayout(null);

        // Add button to panel
        buttonA.setLocation(25, 25);
        buttonA.setSize(150, 25);
        contentPanel.add(buttonA);

        // Add button to panel
        buttonB.setLocation(25, 75);
        buttonB.setSize(150, 25);
        contentPanel.add(buttonB);

        // Add button to panel
        buttonC.setLocation(25, 125);
        buttonC.setSize(150, 25);
        contentPanel.add(buttonC);

        // Add textarea to panel
        textArea.setLocation(25, 175);
        textArea.setSize(300, 50);
        contentPanel.add(textArea);

        // Add actionlisteners to buttons.
        Listener listener = new Listener( );
        buttonA.addActionListener(listener);
        buttonB.addActionListener(listener);
        buttonC.addActionListener(listener);

        // Set the panel to be used to display
        // controls on the frame.
        this.setContentPane(contentPanel);

        // Set width of frame to 400 pixels and
        // height to 500 pixels.
        this.setSize(400, 300);

        // Make frame visible.
        this.setVisible(true);
    }

    // Private inner class for the listener that
    // listens for button clicks.
    private class Listener implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            JButton btn = (JButton) e.getSource( );
            textArea.setText(btn.getText( ) +
                    " was pressed.");
        }
    }
}