6939261: Since 1.6.0_18 JMenus at JMenuBar are not selectable by their Mnemonic key anymore

Reviewed-by: peterz

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

@@ -196,6 +196,10 @@ public class BasicMenuUI extends BasicMenuItemUI
         return getHandler();
     }
 
+    protected MenuKeyListener createMenuKeyListener(JComponent c) {
+        return (MenuKeyListener)getHandler();
+    }
+
     public Dimension getMaximumSize(JComponent c) {
         if (((JMenu)menuItem).isTopLevelMenu() == true) {
             Dimension d = c.getPreferredSize();
@@ -397,7 +401,7 @@ public class BasicMenuUI extends BasicMenuItemUI
         public void stateChanged(ChangeEvent e) { }
     }
 
-    private class Handler extends BasicMenuItemUI.Handler {
+    private class Handler extends BasicMenuItemUI.Handler implements MenuKeyListener {
         //
         // PropertyChangeListener
         //
@@ -580,5 +584,48 @@ public class BasicMenuUI extends BasicMenuItemUI
         }
         public void menuDragMouseExited(MenuDragMouseEvent e) {}
         public void menuDragMouseReleased(MenuDragMouseEvent e) {}
+
+        //
+        // MenuKeyListener
+        //
+        /**
+         * Open the Menu
+         */
+        public void menuKeyTyped(MenuKeyEvent e) {
+            if (!crossMenuMnemonic && BasicPopupMenuUI.getLastPopup() != null) {
+                // when crossMenuMnemonic is not set, we don't open a toplevel
+                // menu if another toplevel menu is already open
+                return;
+            }
+
+            if (BasicPopupMenuUI.getPopups().size() != 0) {
+                //Fix 6939261: to return in case not on the main menu
+                //and has a pop-up.
+                //after return code will be handled in BasicPopupMenuUI.java
+                return;
+            }
+
+            char key = Character.toLowerCase((char)menuItem.getMnemonic());
+            MenuElement path[] = e.getPath();
+            if (key == Character.toLowerCase(e.getKeyChar())) {
+                JPopupMenu popupMenu = ((JMenu)menuItem).getPopupMenu();
+                ArrayList newList = new ArrayList(Arrays.asList(path));
+                newList.add(popupMenu);
+                MenuElement subs[] = popupMenu.getSubElements();
+                MenuElement sub =
+                        BasicPopupMenuUI.findEnabledChild(subs, -1, true);
+                if(sub != null) {
+                    newList.add(sub);
+                }
+                MenuSelectionManager manager = e.getMenuSelectionManager();
+                MenuElement newPath[] = new MenuElement[0];;
+                newPath = (MenuElement[]) newList.toArray(newPath);
+                manager.setSelectedPath(newPath);
+                e.consume();
+            }
+        }
+
+        public void menuKeyPressed(MenuKeyEvent e) {}
+        public void menuKeyReleased(MenuKeyEvent e) {}
     }
 }