/*

 * Copyright (c) 2003, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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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 */

package sun.awt;

import java.awt.Component;

import java.awt.Window;

import java.awt.Canvas;

import java.awt.Scrollbar;

import java.awt.Panel;

import java.awt.event.FocusEvent;

import java.awt.peer.KeyboardFocusManagerPeer;

import java.awt.peer.ComponentPeer;

import sun.awt.AWTAccessor.ComponentAccessor;

import sun.util.logging.PlatformLogger;

public abstract class KeyboardFocusManagerPeerImpl implements KeyboardFocusManagerPeer {

    private static final PlatformLogger focusLog = PlatformLogger.getLogger("sun.awt.focus.KeyboardFocusManagerPeerImpl");

    private static class KfmAccessor {

        private static AWTAccessor.KeyboardFocusManagerAccessor instance =

                AWTAccessor.getKeyboardFocusManagerAccessor();

    }

    // The constants are copied from java.awt.KeyboardFocusManager

    public static final int SNFH_FAILURE         = 0;

    public static final int SNFH_SUCCESS_HANDLED = 1;

    public static final int SNFH_SUCCESS_PROCEED = 2;

    @Override

    public void clearGlobalFocusOwner(Window activeWindow) {

        if (activeWindow != null) {

            Component focusOwner = activeWindow.getFocusOwner();

            if (focusLog.isLoggable(PlatformLogger.Level.FINE)) {

                focusLog.fine("Clearing global focus owner " + focusOwner);

            }

            if (focusOwner != null) {

                FocusEvent fl = new FocusEvent(focusOwner, FocusEvent.FOCUS_LOST, false, null,

                                                     FocusEvent.Cause.CLEAR_GLOBAL_FOCUS_OWNER);

                SunToolkit.postPriorityEvent(fl);

            }

        }

    }

    /*

     * WARNING: Don't call it on the Toolkit thread.

     *

     * Checks if the component:

     * 1) accepts focus on click (in general)

     * 2) may be a focus owner (in particular)

     */

    public static boolean shouldFocusOnClick(Component component) {

        boolean acceptFocusOnClick = false;

        // A component is generally allowed to accept focus on click

        // if its peer is focusable. There're some exceptions though.

        // CANVAS & SCROLLBAR accept focus on click

        final ComponentAccessor acc = AWTAccessor.getComponentAccessor();

        if (component instanceof Canvas ||

            component instanceof Scrollbar)

        {

            acceptFocusOnClick = true;

        // PANEL, empty only, accepts focus on click

        } else if (component instanceof Panel) {

            acceptFocusOnClick = (((Panel)component).getComponentCount() == 0);

        // Other components

        } else {

            ComponentPeer peer = (component != null ? acc.getPeer(component) : null);

            acceptFocusOnClick = (peer != null ? peer.isFocusable() : false);

        }

        return acceptFocusOnClick && acc.canBeFocusOwner(component);

    }

    /*

     * Posts proper lost/gain focus events to the event queue.

     */

    @SuppressWarnings("deprecation")

    public static boolean deliverFocus(Component lightweightChild,

                                       Component target,

                                       boolean temporary,

                                       boolean focusedWindowChangeAllowed,

                                       long time,

                                       FocusEvent.Cause cause,

                                       Component currentFocusOwner) // provided by the descendant peers

    {

        if (lightweightChild == null) {

            lightweightChild = target;

        }

        Component currentOwner = currentFocusOwner;

        if (currentOwner != null && !currentOwner.isDisplayable()) {

            currentOwner = null;

        }

        if (currentOwner != null) {

            FocusEvent fl = new FocusEvent(currentOwner, FocusEvent.FOCUS_LOST,

                                                 false, lightweightChild, cause);

            if (focusLog.isLoggable(PlatformLogger.Level.FINER)) {

                focusLog.finer("Posting focus event: " + fl);

            }

            SunToolkit.postEvent(SunToolkit.targetToAppContext(currentOwner), fl);

        }

        FocusEvent fg = new FocusEvent(lightweightChild, FocusEvent.FOCUS_GAINED,

                                             false, currentOwner, cause);

        if (focusLog.isLoggable(PlatformLogger.Level.FINER)) {

            focusLog.finer("Posting focus event: " + fg);

        }

        SunToolkit.postEvent(SunToolkit.targetToAppContext(lightweightChild), fg);

        return true;

    }

    // WARNING: Don't call it on the Toolkit thread.

    }

    // WARNING: Don't call it on the Toolkit thread.

    public static int shouldNativelyFocusHeavyweight(Component heavyweight,

                                                     Component descendant,

                                                     boolean temporary,

                                                     boolean focusedWindowChangeAllowed,

                                                     long time,

                                                     FocusEvent.Cause cause)

    {

        return KfmAccessor.instance.shouldNativelyFocusHeavyweight(

            heavyweight, descendant, temporary, focusedWindowChangeAllowed,

                time, cause);

    }

    public static void removeLastFocusRequest(Component heavyweight) {

        KfmAccessor.instance.removeLastFocusRequest(heavyweight);

    }

    // WARNING: Don't call it on the Toolkit thread.

    public static boolean processSynchronousLightweightTransfer(Component heavyweight,

                                                                Component descendant,

                                                                boolean temporary,

                                                                boolean focusedWindowChangeAllowed,

                                                                long time)

    {

        return KfmAccessor.instance.processSynchronousLightweightTransfer(

            heavyweight, descendant, temporary, focusedWindowChangeAllowed,

                time);

    }

}