Adding a simple Enter key functionality to my program in Java

I have a little Java program fully working. And I would like to make the "Enter" key working when I enter a pin Code. As I am writing this post, I can only click on the button to make it work, so I'd like to add this simple functionality without changing all the code.

This is the reason of my post, because I have found several links for it, but none of them corresponds to my situation, knowing that I already have a code working. I need to adapt what I have found there :

Allowing the "Enter" key to press the submit button, as opposed to only using MouseClick http://tips4java.wordpress.com/2008/10/10/key-bindings/ http://docs.oracle.com/javase/tutorial/uiswing/misc/keybinding.html http://www.javaprogrammingforums.com/java-swing-tutorials/3171-jbutton-enter-key-keyboard-action.html http://www.rgagnon.com/javadetails/java-0253.html

The fact that they're all showing solution from nohting does not help me because I can not use what they did in my own program.

Enter key

As you can see, this is the "OK" button I need to be clicked or pressed by "Enter"

Here's my code, what do you suggest to have the Enter key working?

import java.io.*;
import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;
import javax.swing.*;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
import javax.swing.text.PlainDocument;
import java.awt.*;
import java.awt.event.*;

public class Main extends JFrame {

    private static final long serialVersionUID = 1L;

    private JPanel container = new JPanel();
    private JPasswordField p1 = new JPasswordField(4);
    private JLabel label = new JLabel("Enter Pin: ");
    private JButton b = new JButton("OK");


    public Main() {
        this.setTitle("NEEDS");
        this.setSize(300, 500);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setLocationRelativeTo(null);

        container.setBackground(Color.white);
        container.setLayout(new BorderLayout());
        container.add(p1);
        JPanel top = new JPanel();

        PlainDocument document =(PlainDocument)p1.getDocument();

        b.addActionListener(new BoutonListener());

        top.add(label);
        top.add(p1);
        p1.setEchoChar('*');
        top.add(b);


        document.setDocumentFilter(new DocumentFilter(){

            @Override
            public void replace(DocumentFilter.FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {
                String string =fb.getDocument().getText(0, fb.getDocument().getLength())+text;

                if(string.length() <= 4)
                super.replace(fb, offset, length, text, attrs); //To change body of generated methods, choose Tools | Templates.
            }
        });

        this.setContentPane(top);
        this.setVisible(true);
    }

    class BoutonListener implements ActionListener {
        private final AtomicInteger nbTry = new AtomicInteger(0);
        ArrayList<Integer> pins = readPinsData(new File("bdd.txt"));

        @SuppressWarnings("deprecation")
        public void actionPerformed(ActionEvent e) {
            if (nbTry.get() > 2) {
                JOptionPane.showMessageDialog(null,
                        "Pin blocked due to 3 wrong tries");
                return;
            }
            final String passEntered=p1.getText().replaceAll("\u00A0", "");
            if (passEntered.length() != 4) {
                JOptionPane.showMessageDialog(null, "Pin must be 4 digits");
                return;
            }
            //JOptionPane.showMessageDialog(null, "Checking...");
            //System.out.println("Checking...");
            SwingWorker<Void, Void> worker = new SwingWorker<Void, Void>() {
                @Override
                protected Void doInBackground() throws Exception {
                    boolean authenticated = false;
                    ImageIcon imgAngry = new ImageIcon("angry.png");
                    ImageIcon imgHappy = new ImageIcon("happy.png");

                    if (pins.contains(Integer.parseInt(passEntered))) {
                        JOptionPane.showMessageDialog(null, "Pin correct", "Good Pin", JOptionPane.INFORMATION_MESSAGE, imgHappy);
                        authenticated = true;
                    }

                    if (!authenticated) {
                        JOptionPane.showMessageDialog(null, "Wrong Pin", "Wrong Pin", JOptionPane.INFORMATION_MESSAGE, imgAngry);
                        nbTry.incrementAndGet();
                    }
                    return null;
                }
            };
            worker.execute();
        }

    }

    // Reading bdd.txt file
    static public ArrayList<Integer> readPinsData(File dataFile) {
        final ArrayList<Integer> data=new ArrayList<Integer>();
        try {
            BufferedReader reader = new BufferedReader(new FileReader(dataFile));
            String line;
            try {
                while ((line = reader.readLine()) != null) {
                    try {
                        data.add(Integer.parseInt(line));
                    } catch (NumberFormatException e) {
                        e.printStackTrace();
                        System.err.printf("error parsing line '%s'\n", line);
                    }
                }
            } finally {
                reader.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
            System.err.println("error:"+e.getMessage());
        }

        return data;
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Main();
            }
        });

    }
}

Solution

JTextField (which JPasswordField inherits from) provides ActionListener support for just this functionality.

p1.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent evt) {
        b.doClick(); // Re-use the Ok buttons ActionListener...
    }
});

Take a look at How to use text fields for more details