1 /*
   2  * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package sun.awt;
  26 
  27 import java.awt.Component;
  28 import java.awt.Window;
  29 import java.awt.Canvas;
  30 import java.awt.Scrollbar;
  31 import java.awt.Panel;
  32 
  33 import java.awt.event.FocusEvent;
  34 
  35 import java.awt.peer.KeyboardFocusManagerPeer;
  36 import java.awt.peer.ComponentPeer;
  37 
  38 import sun.awt.AWTAccessor.ComponentAccessor;
  39 import sun.util.logging.PlatformLogger;
  40 
  41 public abstract class KeyboardFocusManagerPeerImpl implements KeyboardFocusManagerPeer {
  42 
  43     private static final PlatformLogger focusLog = PlatformLogger.getLogger("sun.awt.focus.KeyboardFocusManagerPeerImpl");
  44 
  45     private static class KfmAccessor {
  46         private static AWTAccessor.KeyboardFocusManagerAccessor instance =
  47                 AWTAccessor.getKeyboardFocusManagerAccessor();
  48     }
  49 
  50     // The constants are copied from java.awt.KeyboardFocusManager
  51     public static final int SNFH_FAILURE         = 0;
  52     public static final int SNFH_SUCCESS_HANDLED = 1;
  53     public static final int SNFH_SUCCESS_PROCEED = 2;
  54 
  55     @Override
  56     public void clearGlobalFocusOwner(Window activeWindow) {
  57         if (activeWindow != null) {
  58             Component focusOwner = activeWindow.getFocusOwner();
  59             if (focusLog.isLoggable(PlatformLogger.Level.FINE)) {
  60                 focusLog.fine("Clearing global focus owner " + focusOwner);
  61             }
  62             if (focusOwner != null) {
  63                 FocusEvent fl = new FocusEvent(focusOwner, FocusEvent.FOCUS_LOST, false, null,
  64                                                      FocusEvent.Cause.CLEAR_GLOBAL_FOCUS_OWNER);
  65                 SunToolkit.postPriorityEvent(fl);
  66             }
  67         }
  68     }
  69 
  70     /*
  71      * WARNING: Don't call it on the Toolkit thread.
  72      *
  73      * Checks if the component:
  74      * 1) accepts focus on click (in general)
  75      * 2) may be a focus owner (in particular)
  76      */
  77     public static boolean shouldFocusOnClick(Component component) {
  78         boolean acceptFocusOnClick = false;
  79 
  80         // A component is generally allowed to accept focus on click
  81         // if its peer is focusable. There're some exceptions though.
  82 
  83 
  84         // CANVAS & SCROLLBAR accept focus on click
  85         final ComponentAccessor acc = AWTAccessor.getComponentAccessor();
  86         if (component instanceof Canvas ||
  87             component instanceof Scrollbar)
  88         {
  89             acceptFocusOnClick = true;
  90 
  91         // PANEL, empty only, accepts focus on click
  92         } else if (component instanceof Panel) {
  93             acceptFocusOnClick = (((Panel)component).getComponentCount() == 0);
  94 
  95 
  96         // Other components
  97         } else {
  98             ComponentPeer peer = (component != null ? acc.getPeer(component) : null);
  99             acceptFocusOnClick = (peer != null ? peer.isFocusable() : false);
 100         }
 101         return acceptFocusOnClick && acc.canBeFocusOwner(component);
 102     }
 103 
 104     /*
 105      * Posts proper lost/gain focus events to the event queue.
 106      */
 107     @SuppressWarnings("deprecation")
 108     public static boolean deliverFocus(Component lightweightChild,
 109                                        Component target,
 110                                        boolean temporary,
 111                                        boolean focusedWindowChangeAllowed,
 112                                        long time,
 113                                        FocusEvent.Cause cause,
 114                                        Component currentFocusOwner) // provided by the descendant peers
 115     {
 116         if (lightweightChild == null) {
 117             lightweightChild = target;
 118         }
 119 
 120         Component currentOwner = currentFocusOwner;
 121         if (currentOwner != null && !currentOwner.isDisplayable()) {
 122             currentOwner = null;
 123         }
 124         if (currentOwner != null) {
 125             FocusEvent fl = new FocusEvent(currentOwner, FocusEvent.FOCUS_LOST,
 126                                                  false, lightweightChild, cause);
 127 
 128             if (focusLog.isLoggable(PlatformLogger.Level.FINER)) {
 129                 focusLog.finer("Posting focus event: " + fl);
 130             }
 131             SunToolkit.postEvent(SunToolkit.targetToAppContext(currentOwner), fl);
 132         }
 133 
 134         FocusEvent fg = new FocusEvent(lightweightChild, FocusEvent.FOCUS_GAINED,
 135                                              false, currentOwner, cause);
 136 
 137         if (focusLog.isLoggable(PlatformLogger.Level.FINER)) {
 138             focusLog.finer("Posting focus event: " + fg);
 139         }
 140         SunToolkit.postEvent(SunToolkit.targetToAppContext(lightweightChild), fg);
 141         return true;
 142     }
 143 
 144     // WARNING: Don't call it on the Toolkit thread.
 145     public static void requestFocusFor(Component target, FocusEvent.Cause cause) {
 146         AWTAccessor.getComponentAccessor().requestFocus(target, cause);
 147     }
 148 
 149     // WARNING: Don't call it on the Toolkit thread.
 150     public static int shouldNativelyFocusHeavyweight(Component heavyweight,
 151                                                      Component descendant,
 152                                                      boolean temporary,
 153                                                      boolean focusedWindowChangeAllowed,
 154                                                      long time,
 155                                                      FocusEvent.Cause cause)
 156     {
 157         return KfmAccessor.instance.shouldNativelyFocusHeavyweight(
 158             heavyweight, descendant, temporary, focusedWindowChangeAllowed,
 159                 time, cause);
 160     }
 161 
 162     public static void removeLastFocusRequest(Component heavyweight) {
 163         KfmAccessor.instance.removeLastFocusRequest(heavyweight);
 164     }
 165 
 166     // WARNING: Don't call it on the Toolkit thread.
 167     public static boolean processSynchronousLightweightTransfer(Component heavyweight,
 168                                                                 Component descendant,
 169                                                                 boolean temporary,
 170                                                                 boolean focusedWindowChangeAllowed,
 171                                                                 long time)
 172     {
 173         return KfmAccessor.instance.processSynchronousLightweightTransfer(
 174             heavyweight, descendant, temporary, focusedWindowChangeAllowed,
 175                 time);
 176     }
 177 }
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