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| 1 | /* | ||
| 2 | * Copyright (c) 2001, 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 java.awt; | ||
| 26 | |||
| 27 | import java.awt.event.KeyEvent; | ||
| 28 | |||
| 29 | |||
| 30 | /** | ||
| 31 | * A KeyEventPostProcessor cooperates with the current KeyboardFocusManager | ||
| 32 | * in the final resolution of all unconsumed KeyEvents. KeyEventPostProcessors | ||
| 33 | * registered with the current KeyboardFocusManager will receive KeyEvents | ||
| 34 | * after the KeyEvents have been dispatched to and handled by their targets. | ||
| 35 | * KeyEvents that would have been otherwise discarded because no Component in | ||
| 36 | * the application currently owns the focus will also be forwarded to | ||
| 37 | * registered KeyEventPostProcessors. This will allow applications to implement | ||
| 38 | * features that require global KeyEvent post-handling, such as menu shortcuts. | ||
| 39 | * <p> | ||
| 40 | * Note that the KeyboardFocusManager itself implements KeyEventPostProcessor. | ||
| 41 | * By default, the current KeyboardFocusManager will be the final | ||
| 42 | * KeyEventPostProcessor in the chain. The current KeyboardFocusManager cannot | ||
| 43 | * be completely deregistered as a KeyEventPostProcessor. However, if a | ||
| 44 | * KeyEventPostProcessor reports that no further post-processing of the | ||
| 45 | * KeyEvent should take place, the AWT will consider the event fully handled | ||
| 46 | * and will take no additional action with regard to the event. (While it is | ||
| 47 | * possible for client code to register the current KeyboardFocusManager as | ||
| 48 | * a KeyEventPostProcessor one or more times, this is usually unnecessary and | ||
| 49 | * not recommended.) | ||
| 50 | * | ||
| 51 | * @author David Mendenhall | ||
| 52 | * | ||
| 53 | * @see KeyboardFocusManager#addKeyEventPostProcessor | ||
| 54 | * @see KeyboardFocusManager#removeKeyEventPostProcessor | ||
| 55 | * @since 1.4 | ||
| 56 | */ | ||
| 57 | public interface KeyEventPostProcessor { | ||
| 58 | |||
| 59 | /** | ||
| 60 | * This method is called by the current KeyboardFocusManager, requesting | ||
| 61 | * that this KeyEventPostProcessor perform any necessary post-processing | ||
| 62 | * which should be part of the KeyEvent's final resolution. At the time | ||
| 63 | * this method is invoked, typically the KeyEvent has already been | ||
| 64 | * dispatched to and handled by its target. However, if no Component in | ||
| 65 | * the application currently owns the focus, then the KeyEvent has not | ||
| 66 | * been dispatched to any Component. Typically, KeyEvent post-processing | ||
| 67 | * will be used to implement features which require global KeyEvent | ||
| 68 | * post-handling, such as menu shortcuts. Note that if a | ||
| 69 | * KeyEventPostProcessor wishes to dispatch the KeyEvent, it must use | ||
| 70 | * <code>redispatchEvent</code> to prevent the AWT from recursively | ||
| 71 | * requesting that this KeyEventPostProcessor perform post-processing | ||
| 72 | * of the event again. | ||
| 73 | * <p> | ||
| 74 | * If an implementation of this method returns <code>false</code>, then the | ||
| 75 | * KeyEvent is passed to the next KeyEventPostProcessor in the chain, | ||
| 76 | * ending with the current KeyboardFocusManager. If an implementation | ||
| 77 | * returns <code>true</code>, the KeyEvent is assumed to have been fully | ||
| 78 | * handled (although this need not be the case), and the AWT will take no | ||
| 79 | * further action with regard to the KeyEvent. If an implementation | ||
| 80 | * consumes the KeyEvent but returns <code>false</code>, the consumed | ||
| 81 | * event will still be passed to the next KeyEventPostProcessor in the | ||
| 82 | * chain. It is important for developers to check whether the KeyEvent has | ||
| 83 | * been consumed before performing any post-processing of the KeyEvent. By | ||
| 84 | * default, the current KeyboardFocusManager will perform no post- | ||
| 85 | * processing in response to a consumed KeyEvent. | ||
| 86 | * | ||
| 87 | * @param e the KeyEvent to post-process | ||
| 88 | * @return <code>true</code> if the AWT should take no further action with | ||
| 89 | * regard to the KeyEvent; <code>false</code> otherwise | ||
| 90 | * @see KeyboardFocusManager#redispatchEvent | ||
| 91 | */ | ||
| 92 | boolean postProcessKeyEvent(KeyEvent e); | ||
| 93 | } | ||