可以动态刷新可刷新

Question

首先，我是Java的新手。我用4个面板制作GUI（ Mainprogram ）。

image

in centerpanel in Centerpanel 是可jtable显示了来自数据库中的数据。

在 toppanel < / code>中，我将按钮打开新类 /窗口 - （添加客户）带有一些输入字段。单击“保存”按钮数据后，将数据保存到数据库中， dispose（）。数据正确保存到数据库中。问题是保存后如何在主题中刷新表格？提前致谢。

有一些代码：

mainprogram.java

public class MainProgram extends JFrame {
    Connection connection = MysqlConnect.dbConnector();

    private static final long serialVersionUID = 1L;

    public JPanel contentPane;
    public String selectedRowIndex;

    
    Object[][] data;
    String columns[];

    public JPanel centerPanel;

    public JScrollPane  pane;

    private JTable table;

    

    public MainProgram() throws IOException {

        setTitle("Main Program");
        setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        setBounds(100, 100, 1086, 501);
        setLocationRelativeTo(null);

        // setExtendedState(getExtendedState() | JFrame.MAXIMIZED_BOTH);

        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(new BorderLayout(0, 0));
        addWindowListener((WindowListener) new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent we) {
                String ObjButtons[] = { "Yes", "No" };
                int PromptResult = JOptionPane.showOptionDialog(null, "Are you sure you want to exit?", "SkladModule",
                        JOptionPane.DEFAULT_OPTION, JOptionPane.WARNING_MESSAGE, null, ObjButtons, ObjButtons[1]);
                if (PromptResult == 0) {
                    System.exit(0);
                }
            }
        });

        // left panel
        JPanel leftPanel = new JPanel();
        contentPane.add(leftPanel, BorderLayout.WEST);

        // center panel
        centerPanel = new JPanel(new GridLayout());
        centerPanel.setBorder(new TitledBorder(
                new EtchedBorder(EtchedBorder.LOWERED, new Color(255, 255, 255), new Color(160, 160, 160)), "INFO",
                TitledBorder.LEADING, TitledBorder.TOP, null, new Color(0, 0, 0)));
        contentPane.add(centerPanel, BorderLayout.CENTER);

        try {
            int count = 0;
            String query = "SELECT * FROM vehicles";
            String queryRow = "select count(*) from vehicles";

            Statement stm = connection.createStatement();

            ResultSet rows = stm.executeQuery(queryRow);

            if (rows.next()) {
                count = rows.getInt(1);
                rows.close();
            }

            ResultSet res = stm.executeQuery(query);

            // client_id, plate, make, model, year, engine_cc, color, vehicle_owner,
            // vehicle_owner_contact, mechanic, in_garage, service_start, service_end,
            // service_cost, parts_cost, service_paid, notes
            columns = new String[] { "ID", "Plate", "Make", "Model", "Year", "Engine", "Color", "Owner", "Owner Tel.",
                    "In Garage", "Service Paid", "Notes" };
            data = new Object[count][12];
            int i = 0;
            while (res.next()) {
                int id = res.getInt("client_id");

                data[i][0] = id + "";
                data[i][1] = res.getString("plate");
                data[i][2] = res.getString("make");
                data[i][3] = res.getString("model");
                data[i][4] = res.getString("year");
                data[i][5] = res.getString("engine_cc");
                data[i][6] = res.getString("color");
                data[i][7] = res.getString("vehicle_owner");
                data[i][8] = res.getString("vehicle_owner_contact");
                data[i][9] = res.getString("in_garage");
                data[i][10] = res.getString("service_paid");
                data[i][11] = res.getString("notes");

                i++;
            }
            table = new JTable();
            TableModel model = new DefaultTableModel(data, columns);

            table.setModel(model);

            // JTable table = new JTable(data, columns);

            table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
            final TableColumnModel columnModel = table.getColumnModel();
            for (int column = 0; column < table.getColumnCount(); column++) {
                int width = 15; // Min width
                for (int row = 0; row < table.getRowCount(); row++) {
                    TableCellRenderer renderer = table.getCellRenderer(row, column);
                    Component comp = table.prepareRenderer(renderer, row, column);
                    width = Math.max(comp.getPreferredSize().width + 10, width);
                }
                width = Math.max(width, table.getColumnModel().getColumn(column).getPreferredWidth());
                if (width > 300)

                    width = 300;
                columnModel.getColumn(column).setPreferredWidth(width);
            }

            table.setFocusable(false);
            table.setRowSelectionAllowed(true);

            table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
            table.setDefaultEditor(Object.class, null);
            table.setShowGrid(true);
            table.setShowVerticalLines(true);
            pane = new JScrollPane(table);
            centerPanel.add(pane);

            table.addMouseListener(new MouseListener() {
                public void mouseReleased(MouseEvent e) {
                }

                public void mousePressed(MouseEvent e) {

                    selectedRowIndex = table.getModel().getValueAt(table.getSelectedRow(), 0).toString();

                }

                public void mouseExited(MouseEvent e) {
                }

                public void mouseEntered(MouseEvent e) {
                }

                public void mouseClicked(MouseEvent e) {
                }
            });

            JButton btnNewButton = new JButton("New button");
            btnNewButton.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {

                    if (selectedRowIndex != null) {

                        int rowID = Integer.parseInt(selectedRowIndex);

                        System.out.println(rowID);

                    } else {

                        JOptionPane.showMessageDialog(null, "Please select row!", "No selected vehicle",
                                JOptionPane.INFORMATION_MESSAGE);
                    }

                }
            });
            leftPanel.add(btnNewButton);

        } catch (SQLException e) {
            e.printStackTrace();
        }

        // bottom panel
        // create the status bar panel and shove it down the bottom of the frame
        JPanel statusPanel = new JPanel();
        statusPanel.setBorder((Border) new BevelBorder(BevelBorder.LOWERED));
        contentPane.add(statusPanel, BorderLayout.SOUTH);
        statusPanel.setPreferredSize(new Dimension(contentPane.getWidth(), 20));
        statusPanel.setLayout(new BoxLayout(statusPanel, BoxLayout.X_AXIS));
        JLabel statusLabel = new JLabel("");
        statusLabel.setHorizontalAlignment(SwingConstants.LEFT);
        statusPanel.add(statusLabel);
        contentPane.setVisible(true);

        // add username from login to statusbar
        String username = Login.uname;

        statusLabel.setText("Logged user: " + username);

        JPanel topPanel = new JPanel();
        contentPane.add(topPanel, BorderLayout.NORTH);

        BufferedImage buttonIcon = ImageIO
                .read(new File("C:\\Users\\User\\eclipse-workspace\\SkladModule\\images\\plus.png"));
        JButton btnAddCustomer = new JButton(new ImageIcon(buttonIcon));
        btnAddCustomer.setText("ADD");
        // btnAddCustomer.setBorder(null);
        btnAddCustomer.setContentAreaFilled(false);

        btnAddCustomer.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {

                AddCustomer addCustomer;
                try {
                    addCustomer = new AddCustomer();
                    addCustomer.setVisible(true);
                } catch (IOException e1) {

                    e1.printStackTrace();
                }
            }
        });

        topPanel.add(btnAddCustomer);

        JButton btnNewButton_1 = new JButton("New button");
        topPanel.add(btnNewButton_1);
    }

    public void refresh() {
        TableModel model =new DefaultTableModel(data, columns);
        model.insertRow(res.getRow() - 1, row);
        model.addRow(row);
    }
    
    

}

addcustomer.java ：

public class AddCustomer extends JFrame {

    private static final long serialVersionUID = 1L;
    private JTextField plateField;
    private JTextField makeField;
    private JTextField modelField;
    private JTextField yearField;
    private JTextField engineField;
    private JTextField colorField;
    private JTextField ownerField;
    private JTextField ownerPhoneField;

    Connection connection = null;

    public AddCustomer() throws IOException {
        setResizable(false);
        setType(Type.POPUP);
        setTitle("ADD CUSTOMER");
        setBounds(100, 100, 700, 300);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        getContentPane().setLayout(new BorderLayout(0, 0));
        addWindowListener((WindowListener) new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent we) {
                String ObjButtons[] = { "Yes", "No" };
                int PromptResult = JOptionPane.showOptionDialog(null, "Are you sure you want to exit?", "SkladModule",
                        JOptionPane.DEFAULT_OPTION, JOptionPane.WARNING_MESSAGE, null, ObjButtons, ObjButtons[1]);
                if (PromptResult == 0) {
                    dispose();
                }
            }
        });
        JPanel leftPanel = new JPanel();
        leftPanel.setBorder(BorderFactory.createTitledBorder(" CAR INFO "));
        getContentPane().add(leftPanel, BorderLayout.WEST);
        leftPanel.setLayout(new MigLayout("", "[left][][grow,left]", "[][][][][][][][][]"));
        JLabel lblPlate = new JLabel("Plate: *");
        leftPanel.add(lblPlate, "cell 0 1,alignx trailing");

        plateField = new JTextField();
        leftPanel.add(plateField, "cell 2 1,growx");
        plateField.setColumns(10);

        JLabel lblMake = new JLabel("Make: *");
        leftPanel.add(lblMake, "cell 0 2,alignx trailing");

        makeField = new JTextField();
        leftPanel.add(makeField, "cell 2 2,growx");
        makeField.setColumns(10);

        JLabel lblModel = new JLabel("Model: *");
        leftPanel.add(lblModel, "cell 0 3,alignx trailing");

        modelField = new JTextField();
        leftPanel.add(modelField, "cell 2 3,growx");
        modelField.setColumns(10);

        JLabel lblYear = new JLabel("Year: *");
        leftPanel.add(lblYear, "cell 0 4,alignx trailing");

        yearField = new JTextField();
        leftPanel.add(yearField, "cell 2 4,growx");
        yearField.setColumns(10);

        JLabel lblEngCC = new JLabel("Engine size (cc): *");
        leftPanel.add(lblEngCC, "cell 0 5,alignx trailing");

        engineField = new JTextField();
        leftPanel.add(engineField, "cell 2 5,growx");
        engineField.setColumns(10);

        JLabel lblColor = new JLabel("Color: *");
        leftPanel.add(lblColor, "cell 0 6,alignx trailing");

        colorField = new JTextField();
        leftPanel.add(colorField, "cell 2 6,growx");
        colorField.setColumns(10);

        JLabel lblNewLabel = new JLabel("*  Required fields");
        leftPanel.add(lblNewLabel, "cell 2 8");

        JPanel rightPanel = new JPanel();
        rightPanel.setBorder(BorderFactory.createTitledBorder(" CLIENT INFO "));
        getContentPane().add(rightPanel, BorderLayout.CENTER);
        rightPanel.setLayout(new MigLayout("", "[100px:n,trailing][250px:300px:500,trailing]", "[][][][][grow]"));

        JLabel lblOwnerName = new JLabel("Car owner names: *");
        rightPanel.add(lblOwnerName, "cell 0 1,alignx trailing");

        ownerField = new JTextField();
        rightPanel.add(ownerField, "cell 1 1,growx");
        ownerField.setColumns(10);

        JLabel lblOwnerPhone = new JLabel("Car owner telephone: *");
        rightPanel.add(lblOwnerPhone, "cell 0 2,alignx trailing");

        ownerPhoneField = new JTextField();
        rightPanel.add(ownerPhoneField, "cell 1 2,growx");
        ownerPhoneField.setColumns(10);

        JLabel lblNotes = new JLabel("Notes: ");
        rightPanel.add(lblNotes, "cell 0 3,alignx trailing,aligny top");

        JTextArea notesField = new JTextArea(16, 58);
        notesField.setWrapStyleWord(true);
        notesField.setLineWrap(true);
        notesField.setBorder(BorderFactory.createLineBorder(Color.lightGray));
        JScrollPane scrollNotes = new JScrollPane(notesField);
        scrollNotes.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
        rightPanel.add(scrollNotes, "cell 1 3,grow");

        JPanel bottomPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
        getContentPane().add(bottomPanel, BorderLayout.SOUTH);

        BufferedImage saveButtonIcon = ImageIO
                .read(new File("C:\\Users\\User\\eclipse-workspace\\SkladModule\\images\\accept.png"));
        JButton save_btn = new JButton(new ImageIcon(saveButtonIcon));
        save_btn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {

                /*
                 * if (plateField.getText().isBlank() || makeField.getText().isBlank() ||
                 * modelField.getText().isBlank() || yearField.getText().isBlank() ||
                 * engineField.getText().isBlank() || colorField.getText().isBlank() ||
                 * ownerField.getText().isBlank() || ownerPhoneField.getText().isBlank()) {
                 * 
                 * JOptionPane.showMessageDialog(null, "* required fields incomplete. Please
                 * review and resubmit", "Incomplete data", JOptionPane.WARNING_MESSAGE);
                 * 
                 * } else {
                 */

                connection = MysqlConnect.dbConnector();

                try {

                    String query = "INSERT INTO vehicles (plate, make, model, year, engine_cc, color, vehicle_owner, vehicle_owner_contact, notes) VALUES ('"
                            + plateField.getText() + "','" + makeField.getText() + "','" + modelField.getText() + "','"
                            + yearField.getText() + "','" + engineField.getText() + "','" + colorField.getText() + "','"
                            + ownerField.getText() + "','" + ownerPhoneField.getText() + "','" + notesField.getText()
                            + "')";

                    PreparedStatement pst = connection.prepareStatement(query);
                    pst.executeUpdate(query);
                    MainProgram main = new MainProgram();
                    main.refresh();
                    JOptionPane.showMessageDialog(null, "Data was saved", "SUCCESS", JOptionPane.INFORMATION_MESSAGE);
                    dispose();
                    

                } catch (Exception e1) {
                    JOptionPane.showMessageDialog(null, "SQLException: " + e1.getMessage(), "ERROR",
                            JOptionPane.ERROR_MESSAGE);

                }

                /* } */

            }
        });
        save_btn.setText("SAVE");
        save_btn.setBorder(null);
        save_btn.setContentAreaFilled(true);
        save_btn.setToolTipText("SAVE");
        bottomPanel.add(save_btn);

        Component horizontalStrut = Box.createHorizontalStrut(25);
        bottomPanel.add(horizontalStrut);

        BufferedImage cancelButtonIcon = ImageIO
                .read(new File("C:\\Users\\User\\eclipse-workspace\\SkladModule\\images\\remove.png"));
        JButton cancel_btn = new JButton(new ImageIcon(cancelButtonIcon));
        cancel_btn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                dispose();
            }
        });
        cancel_btn.setText("CANCEL");
        cancel_btn.setBorder(null);
        cancel_btn.setContentAreaFilled(false);
        cancel_btn.setToolTipText("CANCEL");
        cancel_btn.setHorizontalAlignment(SwingConstants.RIGHT);
        bottomPanel.add(cancel_btn);

        Component horizontalStrut_1 = Box.createHorizontalStrut(20);
        bottomPanel.add(horizontalStrut_1);

    }

}

Answer 1

您可能有多种方法可以实现这一目标，但是它们基本上都归结为同一事物，即模态对话框。参见如何进行对话有关更多详细信息。

您应该避免从顶级容器延伸，例如 jframe （和 jdialog ）。您不会在课程中添加任何新功能，而是将自己锁定到一个用例中。

以下示例旨在显示您如何使用模态对话框向用户询问输入。通过相同的“黑魔法”，当您显示模式对话框时，代码执行将在对话框可见时停止并在关闭时恢复（不要问，我不在乎，它只是有效）。

这意味着您可以提出一个对话框，然后等待直到关闭，然后继续做出您需要做的任何决定。

您可以...

使用 joptionpane ，它是整洁且方便的API，用于对话。

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.JToolBar;
import javax.swing.SwingUtilities;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.table.AbstractTableModel;

public class Main {
    public static void main(String[] args) {
        new Main();
    }

    public Main() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new MainPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public static class Person {
        private long id;
        private String firstName;
        private String lastName;

        public Person(long id, String firstName, String lastName) {
            this.id = id;
            this.firstName = firstName;
            this.lastName = lastName;
        }

        public long getId() {
            return id;
        }

        public String getFirstName() {
            return firstName;
        }

        public String getLastName() {
            return lastName;
        }

        @Override
        public int hashCode() {
            int hash = 7;
            hash = 37 * hash + (int) (this.id ^ (this.id >>> 32));
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Person other = (Person) obj;
            if (this.id != other.id) {
                return false;
            }
            return true;
        }

    }

    public class PersonPane extends JPanel {
        private Person person;

        private JTextField firstName;
        private JTextField lastName;

        public PersonPane(Person person) {
            this();
            this.person = person;

            if (person == null) {
                return;
            }
            firstName.setText(person.getFirstName());
            lastName.setText(person.getLastName());
        }

        public PersonPane() {
            firstName = new JTextField(10);
            lastName = new JTextField(10);

            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridx = 0;
            gbc.gridy = 0;
            gbc.anchor = GridBagConstraints.LINE_END;
            gbc.insets = new Insets(4, 4, 4, 4);

            add(new JLabel("First name: "), gbc);
            gbc.gridy++;
            add(new JLabel("Last name: "), gbc);

            gbc.gridx++;
            gbc.gridy = 0;
            gbc.anchor = GridBagConstraints.LINE_START;

            add(firstName, gbc);
            gbc.gridy++;
            add(lastName, gbc);
        }

        public Person save() {
            if (person == null) {
                return new Person(System.currentTimeMillis(), firstName.getText(), lastName.getText());
            }
            long id = person.getId();
            return new Person(id, firstName.getText(), lastName.getText());
        }
    }

    public class PersonTableModel extends AbstractTableModel {

        private List<Person> people = new ArrayList<>();
        private List<String> columNames = new ArrayList<>(Arrays.asList(new String[]{"First name", "Last name"}));

        public PersonTableModel() {
        }

        @Override
        public int getRowCount() {
            return people.size();
        }

        @Override
        public int getColumnCount() {
            return columNames.size();
        }

        @Override
        public String getColumnName(int column) {
            return columNames.get(column);
        }

        @Override
        public Class<?> getColumnClass(int columnIndex) {
            return String.class;
        }

        @Override
        public Object getValueAt(int rowIndex, int columnIndex) {
            Person person = people.get(rowIndex);
            switch (columnIndex) {
                case 0:
                    return person.getFirstName();
                case 1:
                    return person.getLastName();
            }
            return null;
        }

        public void addOrUpdate(Person person) {
            int index = people.indexOf(person);
            if (index >= 0) {
                people.set(index, person);
                fireTableRowsUpdated(index, index);
            } else {
                int lastIndex = people.size();
                people.add(person);
                fireTableRowsInserted(lastIndex, lastIndex);
            }
        }

        public Person getPersonAtRow(int row) {
            return people.get(row);
        }

    }

    public class MainPane extends JPanel {

        private PersonTableModel model = new PersonTableModel();

        public MainPane() {
            setLayout(new BorderLayout());

            JButton newPersonButton = new JButton("New");
            newPersonButton.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    PersonPane personPane = new PersonPane();
                    int option = JOptionPane.showConfirmDialog(MainPane.this, personPane, "New Person", JOptionPane.OK_CANCEL_OPTION, JOptionPane.PLAIN_MESSAGE);
                    if (option == JOptionPane.OK_OPTION) {
                        Person person = personPane.save();
                        if (person != null) {
                            model.addOrUpdate(person);
                        }
                    }
                }
            });

            JToolBar toolBar = new JToolBar();
            toolBar.add(newPersonButton);

            JTable table = new JTable(model);
            table.addMouseListener(new MouseAdapter() {
                @Override
                public void mouseClicked(MouseEvent e) {
                    if (e.getClickCount() == 2) {
                        int rowIndex = table.convertRowIndexToModel(table.getSelectedRow());
                        Person person = model.getPersonAtRow(rowIndex);
                        PersonPane personPane = new PersonPane(person);
                        int option = JOptionPane.showConfirmDialog(MainPane.this, personPane, "Edit Person", JOptionPane.OK_CANCEL_OPTION, JOptionPane.PLAIN_MESSAGE);
                        if (option == JOptionPane.OK_OPTION) {
                            person = personPane.save();
                            if (person != null) {
                                model.addOrUpdate(person);
                            }
                        }
                    }
                }
            });

            add(toolBar, BorderLayout.NORTH);
            add(new JScrollPane(table));
        }
    }
}

您可以...

如果您需要更灵活的东西或想要更详细的验证，则可以滚动自己的对话框（和验证工作流），但是您应该看看启用按钮状态的一种手段，并且仍然使用 joptionpane 。

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.JToolBar;
import javax.swing.SwingUtilities;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.table.AbstractTableModel;

public class Main {
    public static void main(String[] args) {
        new Main();
    }

    public Main() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new MainPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public static class Person {
        private long id;
        private String firstName;
        private String lastName;

        public Person(long id, String firstName, String lastName) {
            this.id = id;
            this.firstName = firstName;
            this.lastName = lastName;
        }

        public long getId() {
            return id;
        }

        public String getFirstName() {
            return firstName;
        }

        public String getLastName() {
            return lastName;
        }

        @Override
        public int hashCode() {
            int hash = 7;
            hash = 37 * hash + (int) (this.id ^ (this.id >>> 32));
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Person other = (Person) obj;
            if (this.id != other.id) {
                return false;
            }
            return true;
        }

    }

    public static class PersonPane extends JPanel {
        public interface ValidationObserver {
            public void validStateDidChange(PersonPane source, boolean isValid);
        }

        private Person person;

        private JTextField firstName;
        private JTextField lastName;

        private List<ValidationObserver> validationObservers = new ArrayList<>(8);

        public PersonPane(Person person) {
            this();
            this.person = person;

            if (person == null) {
                return;
            }
            firstName.setText(person.getFirstName());
            lastName.setText(person.getLastName());
        }

        public PersonPane() {
            firstName = new JTextField(10);
            lastName = new JTextField(10);

            DocumentListener documentListener = new DocumentListener() {
                @Override
                public void insertUpdate(DocumentEvent e) {
                    validateForm();
                }

                @Override
                public void removeUpdate(DocumentEvent e) {
                    validateForm();
                }

                @Override
                public void changedUpdate(DocumentEvent e) {
                    validateForm();
                }
            };

            firstName.getDocument().addDocumentListener(documentListener);
            lastName.getDocument().addDocumentListener(documentListener);

            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridx = 0;
            gbc.gridy = 0;
            gbc.anchor = GridBagConstraints.LINE_END;
            gbc.insets = new Insets(4, 4, 4, 4);

            add(new JLabel("First name: "), gbc);
            gbc.gridy++;
            add(new JLabel("Last name: "), gbc);

            gbc.gridx++;
            gbc.gridy = 0;
            gbc.anchor = GridBagConstraints.LINE_START;

            add(firstName, gbc);
            gbc.gridy++;
            add(lastName, gbc);
        }

        public void addValidationObserver(ValidationObserver observer) {
            validationObservers.add(observer);
        }

        public void removeValidationObserver(ValidationObserver observer) {
            validationObservers.remove(observer);
        }

        protected void fireValidateStateDidChange(boolean isValid) {
            for (ValidationObserver observer : validationObservers) {
                observer.validStateDidChange(this, isValid);
            }
        }

        protected void validateForm() {
            boolean isValid = !firstName.getText().isBlank() && !lastName.getText().isBlank();
            fireValidateStateDidChange(isValid);
        }

        public Person save() {
            if (person == null) {
                return new Person(System.currentTimeMillis(), firstName.getText(), lastName.getText());
            }
            long id = person.getId();
            return new Person(id, firstName.getText(), lastName.getText());
        }

        public static Person createPerson(Component parent) {
            return editPerson(parent, null);
        }

        public static Person editPerson(Component parent, Person person) {
            enum State {
                OKAY, CANCEL
            }

            JPanel actionPane = new JPanel(new GridBagLayout());
            JButton okayButton = new JButton("Okay");
            okayButton.setEnabled(false);
            JButton cancelButton = new JButton("Cancel");

            actionPane.add(okayButton);
            actionPane.add(cancelButton);

            PersonPane personPane = new PersonPane(person);
            personPane.addValidationObserver(new ValidationObserver() {
                @Override
                public void validStateDidChange(PersonPane source, boolean isValid) {
                    okayButton.setEnabled(isValid);
                }
            });

            JDialog dialog = new JDialog(SwingUtilities.windowForComponent(parent));
            dialog.setModal(true);
            dialog.add(personPane);
            dialog.add(actionPane, BorderLayout.SOUTH);

            okayButton.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    personPane.putClientProperty("state", State.OKAY);
                    dialog.dispose();
                }
            });
            cancelButton.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    personPane.putClientProperty("state", State.CANCEL);
                    dialog.dispose();
                }
            });

            dialog.pack();
            dialog.setLocationRelativeTo(parent);
            dialog.setVisible(true);

            Object stateValue = personPane.getClientProperty("state");
            if (stateValue instanceof State) {
                State state = (State) stateValue;
                if (state == State.OKAY) {
                    return personPane.save();
                }
            }

            return null;
        }
    }

    public class PersonTableModel extends AbstractTableModel {

        private List<Person> people = new ArrayList<>();
        private List<String> columNames = new ArrayList<>(Arrays.asList(new String[]{"First name", "Last name"}));

        public PersonTableModel() {
        }

        @Override
        public int getRowCount() {
            return people.size();
        }

        @Override
        public int getColumnCount() {
            return columNames.size();
        }

        @Override
        public String getColumnName(int column) {
            return columNames.get(column);
        }

        @Override
        public Class<?> getColumnClass(int columnIndex) {
            return String.class;
        }

        @Override
        public Object getValueAt(int rowIndex, int columnIndex) {
            Person person = people.get(rowIndex);
            switch (columnIndex) {
                case 0:
                    return person.getFirstName();
                case 1:
                    return person.getLastName();
            }
            return null;
        }

        public void addOrUpdate(Person person) {
            int index = people.indexOf(person);
            if (index >= 0) {
                people.set(index, person);
                fireTableRowsUpdated(index, index);
            } else {
                int lastIndex = people.size();
                people.add(person);
                fireTableRowsInserted(lastIndex, lastIndex);
            }
        }

        public Person getPersonAtRow(int row) {
            return people.get(row);
        }

    }

    public class MainPane extends JPanel {

        private PersonTableModel model = new PersonTableModel();

        public MainPane() {
            setLayout(new BorderLayout());

            JButton newPersonButton = new JButton("New");
            newPersonButton.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    Person person = PersonPane.createPerson(MainPane.this);
                    if (person != null) {
                        model.addOrUpdate(person);
                    }
                }
            });

            JToolBar toolBar = new JToolBar();
            toolBar.add(newPersonButton);

            JTable table = new JTable(model);
            table.addMouseListener(new MouseAdapter() {
                @Override
                public void mouseClicked(MouseEvent e) {
                    if (e.getClickCount() == 2) {
                        int rowIndex = table.convertRowIndexToModel(table.getSelectedRow());
                        Person person = model.getPersonAtRow(rowIndex);
                        person = PersonPane.editPerson(MainPane.this, person);
                        if (person != null) {
                            model.addOrUpdate(person);
                        }
                    }
                }
            });

            add(toolBar, BorderLayout.NORTH);
            add(new JScrollPane(table));
        }
    }
}