// Estos son los tipos de servidor de correo electrónico.
private static final String[] TYPES = {"pop3", "imap"};

// Cuadro combinado para tipos de servidor de correo electrónico.
private JComboBox typeComboBox;

// Servidor, nombre de usuario y campos de texto del servidor SMTP.
private JTextField serverTextField, usernameTextField;
private JTextField smtpServerTextField;

// Campo de texto de contraseña.
private JPasswordField passwordField;

// Constructor para el diálogo.
public ConnectDialog(Frame parent) {
    // Llame a super constructor, especificando que el diálogo es modal.
    super(parent, true);

    // Establecer el título del diálogo.
    setTitle("Connect");

    // Manejar eventos de cierre.
    addWindowListener(new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
            actionCancel();
        }
    });

    // Configuración del panel de configuración.
    JPanel settingsPanel = new JPanel();
    settingsPanel.setBorder(
            BorderFactory.createTitledBorder("Connection Settings"));
    GridBagConstraints constraints;
    GridBagLayout layout = new GridBagLayout();
    settingsPanel.setLayout(layout);
    JLabel typeLabel = new JLabel("Type:");
    constraints = new GridBagConstraints();
    constraints.anchor = GridBagConstraints.EAST;
    constraints.insets = new Insets(5, 5, 0, 0);
    layout.setConstraints(typeLabel, constraints);
    settingsPanel.add(typeLabel);
    typeComboBox = new JComboBox(TYPES);
    constraints = new GridBagConstraints();
    constraints.anchor = GridBagConstraints.WEST;
    constraints.gridwidth = GridBagConstraints.REMAINDER;
    constraints.insets = new Insets(5, 5, 0, 5);
    constraints.weightx = 1.0D;
    layout.setConstraints(typeComboBox, constraints);
    settingsPanel.add(typeComboBox);
    JLabel serverLabel = new JLabel("Server:");
    constraints = new GridBagConstraints();
    constraints.anchor = GridBagConstraints.EAST;
    constraints.insets = new Insets(5, 5, 0, 0);
    layout.setConstraints(serverLabel, constraints);
    settingsPanel.add(serverLabel);
    serverTextField = new JTextField(25);
    constraints = new GridBagConstraints();
    constraints.gridwidth = GridBagConstraints.REMAINDER;
    constraints.insets = new Insets(5, 5, 0, 5);
    constraints.weightx = 1.0D;
    layout.setConstraints(serverTextField, constraints);
    settingsPanel.add(serverTextField);
    JLabel usernameLabel = new JLabel("Username:");
    constraints = new GridBagConstraints();
    constraints.anchor = GridBagConstraints.EAST;
    constraints.insets = new Insets(5, 5, 0, 0);
    layout.setConstraints(usernameLabel, constraints);
    settingsPanel.add(usernameLabel);
    usernameTextField = new JTextField();
    constraints = new GridBagConstraints();
    constraints.anchor = GridBagConstraints.WEST;
    constraints.fill = GridBagConstraints.HORIZONTAL;
    constraints.gridwidth = GridBagConstraints.REMAINDER;
    constraints.insets = new Insets(5, 5, 0, 5);
    constraints.weightx = 1.0D;
    layout.setConstraints(usernameTextField, constraints);
    settingsPanel.add(usernameTextField);
    JLabel passwordLabel = new JLabel("Password:");
    constraints = new GridBagConstraints();
    constraints.anchor = GridBagConstraints.EAST;
    constraints.insets = new Insets(5, 5, 5, 0);
    layout.setConstraints(passwordLabel, constraints);
    settingsPanel.add(passwordLabel);
    passwordField = new JPasswordField();
    constraints = new GridBagConstraints();
    constraints.anchor = GridBagConstraints.WEST;
    constraints.fill = GridBagConstraints.HORIZONTAL;
    constraints.gridwidth = GridBagConstraints.REMAINDER;
    constraints.insets = new Insets(5, 5, 5, 5);
    constraints.weightx = 1.0D;
    layout.setConstraints(passwordField, constraints);
    settingsPanel.add(passwordField);
    JLabel smtpServerLabel = new JLabel("SMTP Server:");
    constraints = new GridBagConstraints();
    constraints.anchor = GridBagConstraints.EAST;
    constraints.insets = new Insets(5, 5, 5, 0);
    layout.setConstraints(smtpServerLabel, constraints);
    settingsPanel.add(smtpServerLabel);
    smtpServerTextField = new JTextField(25);
    constraints = new GridBagConstraints();
    constraints.gridwidth = GridBagConstraints.REMAINDER;
    constraints.insets = new Insets(5, 5, 5, 5);
    constraints.weightx = 1.0D;
    layout.setConstraints(smtpServerTextField, constraints);
    settingsPanel.add(smtpServerTextField);

    // Configuración del panel de botones.
    JPanel buttonsPanel = new JPanel();
    JButton connectButton = new JButton("Connect");
    connectButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            actionConnect();
        }
    });
    buttonsPanel.add(connectButton);
    JButton cancelButton = new JButton("Cancel");
    cancelButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            actionCancel();
        }
    });
    buttonsPanel.add(cancelButton);

    // Añadir paneles para mostrar.
    getContentPane().setLayout(new BorderLayout());
    getContentPane().add(settingsPanel, BorderLayout.CENTER);
    getContentPane().add(buttonsPanel, BorderLayout.SOUTH);

    // Diálogo de tamaño a los componentes.
    pack();

    // Centro de diálogo sobre la aplicación.
    setLocationRelativeTo(parent);
}

// Validar la configuración de la conexión y cerrar el cuadro de diálogo.
private void actionConnect() {
    if (serverTextField.getText().trim().length() < 1
            || usernameTextField.getText().trim().length() < 1
            || passwordField.getPassword().length < 1
            || smtpServerTextField.getText().trim().length() < 1) {
        JOptionPane.showMessageDialog(this,
                "One or more settings is missing.",
                "Missing Setting(s)", JOptionPane.ERROR_MESSAGE);
        return;
    }

    // Cerrar diálogo.
    dispose();
}

// Cancelar la conexión y salir del programa.
private void actionCancel() {
    System.exit(0);
}

     //Obtener servidor de correo electrónico
public String getType(){
   return(String) typeComboBox.getSelectedItem();
}

// Obtener servidor de correo electrónico
public String getServer() {
    return serverTextField.getText();
}

// Obtener un nombre de usuario de correo electrónico.
public String getUsername() {
    return usernameTextField.getText();
}

// Obtener contraseña de correo electrónico.
public String getPassword() {
    return new String(passwordField.getPassword());
}

// Obtener correo electrónico del servidor SMTP.
public String getSmtpServer() {
    return smtpServerTextField.getText();
}