8231991: Mouse wheel change focus on awt/swing windows

Summary: Avoid focus logic when only mouse wheel is moved up/down.
Reviewed-by: serb, dmarkov

src/solaris/classes/sun/awt/X11/XBaseWindow.java

@@ -1004,11 +1004,18 @@ public class XBaseWindow {
          * InputEvent.BUTTON_DOWN_MASK.
          * One more bit is reserved for FIRST_HIGH_BIT.
          */
-        if (xbe.get_button() > SunToolkit.MAX_BUTTONS_SUPPORTED) {
+        int theButton = xbe.get_button();
+        if (theButton > SunToolkit.MAX_BUTTONS_SUPPORTED) {
             return;
         }
         int buttonState = 0;
         buttonState = xbe.get_state() & XConstants.ALL_BUTTONS_MASK;
+
+        boolean isWheel = (theButton != XConstants.MouseWheelUp ||
+                           theButton != XConstants.MouseWheelDown);
+
+        // don't give focus if it's just the mouse wheel turning
+        if (!isWheel) {
             switch (xev.get_type()) {
                 case XConstants.ButtonPress:
                     if (buttonState == 0) {
@@ -1029,6 +1036,7 @@ public class XBaseWindow {
                     break;
             }
         }
+    }
     public void handleMotionNotify(XEvent xev) {
     }
     public void handleXCrossingEvent(XEvent xev) {

src/solaris/classes/sun/awt/X11/XConstants.java

@@ -206,6 +206,11 @@ final public class XConstants {
 
     public static final int buttons [] = new int [] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24};
 
+    // those should probably be wrapped in a method or such
+    // as it may be possible to remap them via x11 configuration files
+    public static final int MouseWheelUp = buttons[4];
+    public static final int MouseWheelDown = buttons[5];
+
     /* Notify modes */
 
     public static final int NotifyNormal = 0 ;

test/java/awt/event/MouseWheelEvent/WheelModifier/MouseWheelOnBackgroundComponent.java

+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * 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
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+  @test
+  @key headful
+  @bug 8231991
+  @summary Mouse wheel change focus on awt/swing windows
+  @run main MouseWheelOnBackgroundComponent
+*/
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.FocusEvent;
+import java.awt.event.FocusListener;
+import java.awt.event.WindowEvent;
+
+/**
+ * MouseWheelOnBackgroundComponent
+ *
+ * Tests that wheel events don't change focus on background components
+ */
+public class MouseWheelOnBackgroundComponent {
+
+    private static final String FG = "Foreground";
+    private static final String BG = "Background";
+
+    private static final String SCROLL_PANE = "scroller_";
+    private static final String TEXT_PANE = "text_";
+
+    private static JFrame background;
+    private static JFrame foreground;
+
+    private static final String LOREM_IPSUM = "Sed ut perspiciatis unde omnis iste natus " +
+            "error sit voluptatem accusantium doloremque laudantium, totam " +
+            "rem aperiam, eaque ipsa quae ab illo inventore veritatis et " +
+            "quasi architecto beatae vitae dicta sunt explicabo. Nemo enim " +
+            "ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, " +
+            "sed quia consequuntur magni dolores eos qui ratione voluptatem sequi " +
+            "nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit " +
+            "amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora " +
+            "incidunt ut labore et dolore magnam aliquam quaerat voluptatem. " +
+            "Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis " +
+            "suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis " +
+            "autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil " +
+            "molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla " +
+            "pariatur?";
+
+    private static class FocusReporter implements FocusListener {
+
+        private JComponent pane;
+
+        Component lastFocusedComponent;
+
+        public FocusReporter() {
+        }
+
+        @Override
+        public void focusGained(FocusEvent e) {
+            lastFocusedComponent = e.getComponent();
+        }
+
+        @Override
+        public void focusLost(FocusEvent e) {
+            lastFocusedComponent = null;
+        }
+    }
+
+    private static FocusReporter reporter;
+
+    public static void main(String[] args) throws Exception  {
+
+        boolean passed = false;
+
+        SwingUtilities.invokeAndWait(() -> {
+            reporter = new FocusReporter();
+
+            foreground = createFrame(FG, 100, 0, reporter);
+            background = createFrame(BG, 0, 100, reporter);
+
+            background.pack();
+            background.setVisible(true);
+
+            foreground.pack();
+            foreground.setVisible(true);
+        });
+
+        SwingUtilities.invokeAndWait(() -> {
+            foreground.toFront();
+        });
+
+        Robot robot = new Robot();
+        robot.waitForIdle();
+
+        robot.mouseMove(50, 300);
+        robot.waitForIdle();
+
+        robot.mouseWheel(-100);
+        robot.waitForIdle();
+
+        String shouldBeFocusedComponentName = TEXT_PANE + FG;
+        Component actual = reporter.lastFocusedComponent;
+        if (reporter.lastFocusedComponent != null &&
+            shouldBeFocusedComponentName.equals(actual.getName()))
+        {
+            passed = true;
+        }
+
+        robot.waitForIdle();
+
+        SwingUtilities.invokeAndWait(() -> {
+            foreground.dispatchEvent(new WindowEvent(foreground, WindowEvent.WINDOW_CLOSING));
+            background.dispatchEvent(new WindowEvent(background, WindowEvent.WINDOW_CLOSING));
+        });
+
+        robot.waitForIdle();
+
+        if (!passed) {
+            throw new RuntimeException("Wrong component has focus: " + actual);
+        }
+    }
+
+    private static JFrame createFrame(String name, int x, int y, FocusReporter reporter) {
+        JFrame frame = new JFrame(name);
+        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
+        frame.setBounds(x, y, 600, 600);
+        frame.setPreferredSize(new Dimension(600, 600));
+
+        JTextArea text = new JTextArea();
+        text.setText(LOREM_IPSUM);
+        for (int i = 0; i < 10; i++) {
+            text.append(LOREM_IPSUM);
+        }
+
+        text.setLineWrap(true);
+        text.setName(TEXT_PANE + name);
+        text.addFocusListener(reporter);
+
+        JScrollPane scroller = new JScrollPane(text);
+        scroller.setName(SCROLL_PANE + name);
+        scroller.setWheelScrollingEnabled(true);
+        scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
+        scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
+        scroller.addFocusListener(reporter);
+
+        frame.add(scroller);
+
+        return frame;
+    }
+}