MessageDigestTest.java Source code

Introduction

Here is the source code for MessageDigestTest.java

Source

import java.awt.Container;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import javax.swing.ButtonGroup;
import javax.swing.JCheckBox;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class MessageDigestTest {
    public static void main(String[] args) {
        JFrame f = new MessageDigestFrame();
        f.show();
    }
}

class MessageDigestFrame extends JFrame {
    public MessageDigestFrame() {
        setTitle("MessageDigestTest");
        setSize(400, 200);
        addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });

        JPanel panel = new JPanel();
        ButtonGroup group = new ButtonGroup();
        ActionListener listener = new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                JCheckBox b = (JCheckBox) event.getSource();
                setAlgorithm(b.getText());
            }
        };
        addCheckBox(panel, "SHA-1", group, true, listener);
        addCheckBox(panel, "MD5", group, false, listener);

        Container contentPane = getContentPane();

        contentPane.add(panel, "North");
        contentPane.add(new JScrollPane(message), "Center");
        contentPane.add(digest, "South");
        digest.setFont(new Font("Monospaced", Font.PLAIN, 12));

        setAlgorithm("SHA-1");

        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("File");
        JMenuItem fileDigestItem = new JMenuItem("File digest");
        fileDigestItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                loadFile();
            }
        });
        menu.add(fileDigestItem);
        JMenuItem textDigestItem = new JMenuItem("Text area digest");
        textDigestItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                String m = message.getText();
                computeDigest(m.getBytes());
            }
        });
        menu.add(textDigestItem);
        menuBar.add(menu);
        setJMenuBar(menuBar);
    }

    public void addCheckBox(Container c, String name, ButtonGroup g, boolean selected, ActionListener listener) {
        JCheckBox b = new JCheckBox(name, selected);
        c.add(b);
        g.add(b);
        b.addActionListener(listener);
    }

    public void setAlgorithm(String alg) {
        try {
            currentAlgorithm = MessageDigest.getInstance(alg);
            digest.setText("");
        } catch (NoSuchAlgorithmException e) {
            digest.setText("" + e);
        }
    }

    public void loadFile() {
        JFileChooser chooser = new JFileChooser();
        chooser.setCurrentDirectory(new File("."));

        int r = chooser.showOpenDialog(this);
        if (r == JFileChooser.APPROVE_OPTION) {
            String name = chooser.getSelectedFile().getAbsolutePath();
            computeDigest(loadBytes(name));
        }
    }

    public byte[] loadBytes(String name) {
        FileInputStream in = null;

        try {
            in = new FileInputStream(name);
            ByteArrayOutputStream buffer = new ByteArrayOutputStream();
            int ch;
            while ((ch = in.read()) != -1)
                buffer.write(ch);
            return buffer.toByteArray();
        } catch (IOException e) {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e2) {
                }
            }
            return null;
        }
    }

    public void computeDigest(byte[] b) {
        currentAlgorithm.reset();
        currentAlgorithm.update(b);
        byte[] hash = currentAlgorithm.digest();
        String d = "";
        for (int i = 0; i < hash.length; i++) {
            int v = hash[i] & 0xFF;
            if (v < 16)
                d += "0";
            d += Integer.toString(v, 16).toUpperCase() + " ";
        }
        digest.setText(d);
    }

    private JTextArea message = new JTextArea();

    private JTextField digest = new JTextField();

    private MessageDigest currentAlgorithm;
}