/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.GridLayout;

import java.awt.Robot;

import java.awt.event.FocusAdapter;

import java.awt.event.FocusEvent;

import java.awt.event.KeyEvent;

import javax.swing.JFrame;

import javax.swing.SwingUtilities;

import javax.swing.UIManager;

import javax.swing.JPanel;

import javax.swing.ButtonGroup;

import javax.swing.JComponent;

import javax.swing.JRadioButton;

import javax.swing.JToggleButton;

import javax.swing.LayoutFocusTraversalPolicy;

import javax.swing.UnsupportedLookAndFeelException;

public class ButtonGroupLayoutTraversalTest {

    static int nx = 3;

    static int ny = 3;

    static int focusCnt[] = new int[nx * ny];

    private static JFrame window;

    public static void main(String[] args) throws Exception {

        SwingUtilities.invokeAndWait(() -> changeLAF());

        SwingUtilities.invokeAndWait(() -> initLayout(nx, ny));

        Robot robot = new Robot();

        robot.setAutoDelay(100);

        robot.waitForIdle();

        robot.delay(200);

        for (int i = 0; i < nx * ny - nx * ny / 2 - 1; i++) {

            robot.keyPress(KeyEvent.VK_RIGHT);

            robot.keyRelease(KeyEvent.VK_RIGHT);

        }

        for (int i = 0; i < nx * ny / 2; i++) {

            robot.keyPress(KeyEvent.VK_TAB);

            robot.keyRelease(KeyEvent.VK_TAB);

        }

        robot.waitForIdle();

        robot.delay(200);

        for (int i = 0; i < nx * ny; i++) {

            if (focusCnt[i] < 1) {

                SwingUtilities.invokeLater(window::dispose);

                throw new RuntimeException("Component " + i

                        + " is not reachable in the forward focus cycle");

            } else if (focusCnt[i] > 1) {

                SwingUtilities.invokeLater(window::dispose);

                throw new RuntimeException("Component " + i

                        + " got focus more than once in the forward focus cycle");

            }

        }

        for (int i = 0; i < nx * ny / 2; i++) {

            robot.keyPress(KeyEvent.VK_SHIFT);

            robot.keyPress(KeyEvent.VK_TAB);

            robot.keyRelease(KeyEvent.VK_TAB);

            robot.keyRelease(KeyEvent.VK_SHIFT);

        }

        for (int i = 0; i < nx * ny - nx * ny / 2 - 1; i++) {

            robot.keyPress(KeyEvent.VK_LEFT);

            robot.keyRelease(KeyEvent.VK_LEFT);

        }

        robot.keyPress(KeyEvent.VK_SHIFT);

        robot.keyPress(KeyEvent.VK_TAB);

        robot.keyRelease(KeyEvent.VK_TAB);

        robot.keyRelease(KeyEvent.VK_SHIFT);

        robot.waitForIdle();

        robot.delay(200);

        for (int i = 0; i < nx * ny; i++) {

            if (focusCnt[i] < 2) {

                SwingUtilities.invokeLater(window::dispose);

                throw new RuntimeException("Component " + i

                        + " is not reachable in the backward focus cycle");

            } else if (focusCnt[i] > 2) {

                SwingUtilities.invokeLater(window::dispose);

                throw new RuntimeException("Component " + i

                        + " got focus more than once in the backward focus cycle");

            }

        }

        SwingUtilities.invokeLater(window::dispose);

    }

    private static void changeLAF() {

        String currentLAF = UIManager.getLookAndFeel().toString();

        currentLAF = currentLAF.toLowerCase();

        if (currentLAF.contains("aqua") || currentLAF.contains("nimbus")) {

            try {

                UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");

            } catch (ClassNotFoundException

                    | IllegalAccessException

                    | InstantiationException

                    | UnsupportedLookAndFeelException ex) {

                ex.printStackTrace();

            }

        }

    }

    public static void initLayout(int nx, int ny) {

        window = new JFrame("Test");

        window.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JPanel rootPanel = new JPanel();

        rootPanel.setLayout(new BorderLayout());

        JPanel formPanel = new JPanel(new GridLayout(nx, ny));

        formPanel.setFocusTraversalPolicy(new LayoutFocusTraversalPolicy());

        formPanel.setFocusCycleRoot(true);

        ButtonGroup radioButtonGroup = new ButtonGroup();

        for (int i = 0; i < nx * ny; i++) {

            JToggleButton comp;

            if (i % 2 == 0) {

                comp = new JRadioButton("Grouped component");

                radioButtonGroup.add(comp);

            } else {

                comp = new JRadioButton("Single component");

            }

            formPanel.add(comp);

            int fi = i;

            comp.setBackground(Color.red);

            comp.addFocusListener(new FocusAdapter() {

                @Override

                public void focusGained(FocusEvent e) {

                    focusCnt[fi]++;

                    if (focusCnt[fi] == 1) {

                        ((JComponent) e.getSource())

                                .setBackground(Color.yellow);

                    } else if (focusCnt[fi] == 2) {

                        ((JComponent) e.getSource())

                                .setBackground(Color.green);

                    } else {

                        ((JComponent) e.getSource())

                                .setBackground(Color.red);

                    }

                }

            });

        }

        rootPanel.add(formPanel, BorderLayout.CENTER);

        window.add(rootPanel);

        window.pack();

        window.setVisible(true);

    }

}