/*

 * Copyright (c) 2000, 2013, 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 java.awt.event;

import java.util.EventListener;

/**

 * The listener interface for receiving <code>WindowEvents</code>, including

 * <code>WINDOW_GAINED_FOCUS</code> and <code>WINDOW_LOST_FOCUS</code> events.

 * The class that is interested in processing a <code>WindowEvent</code>

 * either implements this interface (and

 * all the methods it contains) or extends the abstract

 * <code>WindowAdapter</code> class (overriding only the methods of interest).

 * The listener object created from that class is then registered with a

 * <code>Window</code>

 * using the <code>Window</code>'s <code>addWindowFocusListener</code> method.

 * When the <code>Window</code>'s

 * status changes by virtue of it being opened, closed, activated, deactivated,

 * iconified, or deiconified, or by focus being transfered into or out of the

 * <code>Window</code>, the relevant method in the listener object is invoked,

 * and the <code>WindowEvent</code> is passed to it.

 *

 * @author David Mendenhall

 *

 * @see WindowAdapter

 * @see WindowEvent

 * @see <a href="https://docs.oracle.com/javase/tutorial/uiswing/events/windowlistener.html">Tutorial: Writing a Window Listener</a>

 *

 * @since 1.4

 */

public interface WindowFocusListener extends EventListener {

    /**

     * Invoked when the Window is set to be the focused Window, which means

     * that the Window, or one of its subcomponents, will receive keyboard

     * events.

     */

    public void windowGainedFocus(WindowEvent e);

    /**

     * Invoked when the Window is no longer the focused Window, which means

     * that keyboard events will no longer be delivered to the Window or any of

     * its subcomponents.

     */

    public void windowLostFocus(WindowEvent e);

}