1 /*
   2  * Copyright (c) 1996, 2020, 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 
  26 package java.awt.event;
  27 
  28 /**
  29  * An abstract adapter class for receiving keyboard events.
  30  * The methods in this class are empty. This class exists as
  31  * convenience for creating listener objects.
  32  * <P>
  33  * Extend this class to create a {@code KeyEvent} listener
  34  * and override the methods for the events of interest. (If you implement the
  35  * {@code KeyListener} interface, you have to define all of
  36  * the methods in it. This abstract class defines null methods for them
  37  * all, so you can only have to define methods for events you care about.)
  38  * <P>
  39  * Create a listener object using the extended class and then register it with
  40  * a component using the component's {@code addKeyListener}
  41  * method. When a key is pressed, released, or typed,
  42  * the relevant method in the listener object is invoked,
  43  * and the {@code KeyEvent} is passed to it.
  44  *
  45  * @author Carl Quinn
  46  *
  47  * @see KeyEvent
  48  * @see KeyListener
  49  * @see <a href="https://docs.oracle.com/javase/tutorial/uiswing/events/keylistener.html">Tutorial: Writing a Key Listener</a>
  50  *
  51  * @since 1.1
  52  */
  53 public abstract class KeyAdapter implements KeyListener {
  54 
  55     /**
  56      * Constructs a {@code KeyAdapter}.
  57      */
  58     protected KeyAdapter() {}
  59 
  60     /**
  61      * Invoked when a key has been typed.
  62      * This event occurs when a key press is followed by a key release.
  63      */
  64     public void keyTyped(KeyEvent e) {}
  65 
  66     /**
  67      * Invoked when a key has been pressed.
  68      */
  69     public void keyPressed(KeyEvent e) {}
  70 
  71     /**
  72      * Invoked when a key has been released.
  73      */
  74     public void keyReleased(KeyEvent e) {}
  75 }
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