8136998: JComboBox prevents wheel mouse scrolling of JScrollPane

Reviewed-by: serb, alexp

src/share/classes/javax/swing/plaf/basic/BasicComboBoxUI.java

 /*
- * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2016, 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
@@ -125,8 +125,6 @@ public class BasicComboBoxUI extends ComboBoxUI {
     protected MouseMotionListener popupMouseMotionListener;
     protected KeyListener popupKeyListener;
 
-    private MouseWheelListener mouseWheelListener;
-
     // This is used for knowing when to cache the minimum preferred size.
     // If the data in the list changes, the cached value get marked for recalc.
     // Added to the current JComboBox model
@@ -377,10 +375,6 @@ public class BasicComboBoxUI extends ComboBoxUI {
                 comboBox.getModel().addListDataListener( listDataListener );
             }
         }
-
-        if ((mouseWheelListener = createMouseWheelListener()) != null) {
-            comboBox.addMouseWheelListener(mouseWheelListener);
-        }
     }
 
     /**
@@ -427,9 +421,6 @@ public class BasicComboBoxUI extends ComboBoxUI {
                 comboBox.getModel().removeListDataListener( listDataListener );
             }
         }
-        if (mouseWheelListener != null) {
-            comboBox.removeMouseWheelListener(mouseWheelListener);
-        }
     }
 
     /**
@@ -543,10 +534,6 @@ public class BasicComboBoxUI extends ComboBoxUI {
         return handler;
     }
 
-    private MouseWheelListener createMouseWheelListener() {
-        return getHandler();
-    }
-
     //
     // end UI Initialization
     //======================
@@ -1682,8 +1669,7 @@ public class BasicComboBoxUI extends ComboBoxUI {
     //
     private class Handler implements ActionListener, FocusListener,
                                      KeyListener, LayoutManager,
-                                     ListDataListener, PropertyChangeListener,
-                                     MouseWheelListener {
+                                     ListDataListener, PropertyChangeListener {
         //
         // PropertyChangeListener
         //
@@ -1967,10 +1953,6 @@ public class BasicComboBoxUI extends ComboBoxUI {
                 }
             }
         }
-
-        public void mouseWheelMoved(MouseWheelEvent e) {
-            e.consume();
-        }
    }
 
     class DefaultKeySelectionManager implements JComboBox.KeySelectionManager, UIResource {

src/share/classes/javax/swing/plaf/basic/BasicComboPopup.java

 /*
- * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2016, 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
@@ -345,17 +345,26 @@ public class BasicComboPopup extends JPopupMenu implements ComboPopup {
     // PopupMenuListeners.
 
     protected void firePopupMenuWillBecomeVisible() {
+        if (scrollerMouseWheelListener != null) {
+            comboBox.addMouseWheelListener(scrollerMouseWheelListener);
+        }
         super.firePopupMenuWillBecomeVisible();
         // comboBox.firePopupMenuWillBecomeVisible() is called from BasicComboPopup.show() method
         // to let the user change the popup menu from the PopupMenuListener.popupMenuWillBecomeVisible()
     }
 
     protected void firePopupMenuWillBecomeInvisible() {
+        if (scrollerMouseWheelListener != null) {
+            comboBox.removeMouseWheelListener(scrollerMouseWheelListener);
+        }
         super.firePopupMenuWillBecomeInvisible();
         comboBox.firePopupMenuWillBecomeInvisible();
     }
 
     protected void firePopupMenuCanceled() {
+        if (scrollerMouseWheelListener != null) {
+            comboBox.removeMouseWheelListener(scrollerMouseWheelListener);
+        }
         super.firePopupMenuCanceled();
         comboBox.firePopupMenuCanceled();
     }

test/javax/swing/JComboBox/8136998/bug8136998.java

+/*
+ * Copyright (c) 2016, 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.
+ */
+
+import java.awt.AWTException;
+import java.awt.Dimension;
+import java.awt.Point;
+import java.awt.Rectangle;
+import java.awt.Robot;
+import javax.swing.Box;
+import javax.swing.BoxLayout;
+import javax.swing.JComboBox;
+import javax.swing.JFrame;
+import javax.swing.JPanel;
+import javax.swing.JScrollPane;
+import javax.swing.SwingUtilities;
+import javax.swing.UIManager;
+import javax.swing.UIManager.LookAndFeelInfo;
+import javax.swing.UnsupportedLookAndFeelException;
+import javax.swing.WindowConstants;
+
+/* @test
+ * @bug 8136998
+ * @summary Checks that JComboBox does not prevent mouse-wheel scrolling JScrollPane.
+ * @library ../../regtesthelpers
+ * @build Util
+ * @run main bug8136998
+ * @author Alexey Ivanov
+ */
+public class bug8136998 {
+
+    private static final String[] ITEMS = new String[] {
+        "A", "B", "C", "D", "E", "F"
+    };
+
+    private final Robot robot;
+
+    private JFrame frame;
+    private JComboBox comboBox;
+    private JScrollPane scrollPane;
+
+    public static void main(String[] args) throws Exception {
+        iterateLookAndFeels(new bug8136998());
+    }
+
+    protected static void iterateLookAndFeels(final bug8136998 test) throws Exception {
+        LookAndFeelInfo[] lafInfo = UIManager.getInstalledLookAndFeels();
+        for (LookAndFeelInfo info : lafInfo) {
+            try {
+                UIManager.setLookAndFeel(info.getClassName());
+                System.out.println("Look and Feel: " + info.getClassName());
+                test.runTest();
+            } catch (UnsupportedLookAndFeelException e) {
+                System.out.println("Skipping unsupported LaF: " + info);
+            }
+        }
+    }
+
+    public bug8136998() throws AWTException {
+        robot = new Robot();
+        robot.setAutoDelay(200);
+    }
+
+    private void setupUI() {
+        frame = new JFrame();
+        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
+
+        comboBox = new JComboBox<>(ITEMS);
+
+        JPanel scrollable = new JPanel();
+        scrollable.setLayout(new BoxLayout(scrollable, BoxLayout.Y_AXIS));
+
+        scrollable.add(Box.createVerticalStrut(200));
+        scrollable.add(comboBox);
+        scrollable.add(Box.createVerticalStrut(200));
+
+        scrollPane = new JScrollPane(scrollable);
+
+        frame.add(scrollPane);
+
+        frame.setSize(100, 200);
+        frame.setVisible(true);
+    }
+
+    public void runTest() throws Exception {
+        try {
+            SwingUtilities.invokeAndWait(this::setupUI);
+
+            robot.waitForIdle();
+
+            SwingUtilities.invokeAndWait(() ->
+                scrollPane.getViewport().scrollRectToVisible(comboBox.getBounds())
+            );
+            robot.waitForIdle();
+
+            // Move mouse pointer to the center of the combo box
+            Point p = comboBox.getLocationOnScreen();
+            Dimension d = comboBox.getSize();
+            robot.mouseMove(p.x + d.width / 2, p.y + d.height / 2);
+
+            // The currently visible rectangle in scrollPane
+            Rectangle viewRect0 = Util.invokeOnEDT(scrollPane.getViewport()::getViewRect);
+
+            // Scroll the scrollPane with mouse wheel
+            robot.mouseWheel(1);
+            robot.waitForIdle();
+
+            // The updated rectangle
+            Rectangle viewRect1 = Util.invokeOnEDT(scrollPane.getViewport()::getViewRect);
+
+            if (viewRect0.y == viewRect1.y) {
+                throw new RuntimeException("Mouse wheel should have scrolled the JScrollPane");
+            }
+        } finally {
+            if (frame != null) {
+                frame.dispose();
+            }
+        }
+
+        System.out.println("Test passed");
+    }
+}