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| 1 | /* | ||
| 2 | * Copyright (c) 2000, 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 KeyEventDispatcher cooperates with the current KeyboardFocusManager in the | ||
| 32 | * targeting and dispatching of all KeyEvents. KeyEventDispatchers registered | ||
| 33 | * with the current KeyboardFocusManager will receive KeyEvents before they are | ||
| 34 | * dispatched to their targets, allowing each KeyEventDispatcher to retarget | ||
| 35 | * the event, consume it, dispatch the event itself, or make other changes. | ||
| 36 | * <p> | ||
| 37 | * Note that KeyboardFocusManager itself implements KeyEventDispatcher. By | ||
| 38 | * default, the current KeyboardFocusManager will be the sink for all KeyEvents | ||
| 39 | * not dispatched by the registered KeyEventDispatchers. The current | ||
| 40 | * KeyboardFocusManager cannot be completely deregistered as a | ||
| 41 | * KeyEventDispatcher. However, if a KeyEventDispatcher reports that it | ||
| 42 | * dispatched the KeyEvent, regardless of whether it actually did so, the | ||
| 43 | * KeyboardFocusManager will take no further action with regard to the | ||
| 44 | * KeyEvent. (While it is possible for client code to register the current | ||
| 45 | * KeyboardFocusManager as a KeyEventDispatcher one or more times, this is | ||
| 46 | * usually unnecessary and not recommended.) | ||
| 47 | * | ||
| 48 | * @author David Mendenhall | ||
| 49 | * | ||
| 50 | * @see KeyboardFocusManager#addKeyEventDispatcher | ||
| 51 | * @see KeyboardFocusManager#removeKeyEventDispatcher | ||
| 52 | * @since 1.4 | ||
| 53 | */ | ||
| 54 | public interface KeyEventDispatcher { | ||
| 55 | |||
| 56 | /** | ||
| 57 | * This method is called by the current KeyboardFocusManager requesting | ||
| 58 | * that this KeyEventDispatcher dispatch the specified event on its behalf. | ||
| 59 | * This KeyEventDispatcher is free to retarget the event, consume it, | ||
| 60 | * dispatch it itself, or make other changes. This capability is typically | ||
| 61 | * used to deliver KeyEvents to Components other than the focus owner. This | ||
| 62 | * can be useful when navigating children of non-focusable Windows in an | ||
| 63 | * accessible environment, for example. Note that if a KeyEventDispatcher | ||
| 64 | * dispatches the KeyEvent itself, it must use <code>redispatchEvent</code> | ||
| 65 | * to prevent the current KeyboardFocusManager from recursively requesting | ||
| 66 | * that this KeyEventDispatcher dispatch the event again. | ||
| 67 | * <p> | ||
| 68 | * If an implementation of this method returns <code>false</code>, then | ||
| 69 | * the KeyEvent is passed to the next KeyEventDispatcher in the chain, | ||
| 70 | * ending with the current KeyboardFocusManager. If an implementation | ||
| 71 | * returns <code>true</code>, the KeyEvent is assumed to have been | ||
| 72 | * dispatched (although this need not be the case), and the current | ||
| 73 | * KeyboardFocusManager will take no further action with regard to the | ||
| 74 | * KeyEvent. In such a case, | ||
| 75 | * <code>KeyboardFocusManager.dispatchEvent</code> should return | ||
| 76 | * <code>true</code> as well. If an implementation consumes the KeyEvent, | ||
| 77 | * but returns <code>false</code>, the consumed event will still be passed | ||
| 78 | * to the next KeyEventDispatcher in the chain. It is important for | ||
| 79 | * developers to check whether the KeyEvent has been consumed before | ||
| 80 | * dispatching it to a target. By default, the current KeyboardFocusManager | ||
| 81 | * will not dispatch a consumed KeyEvent. | ||
| 82 | * | ||
| 83 | * @param e the KeyEvent to dispatch | ||
| 84 | * @return <code>true</code> if the KeyboardFocusManager should take no | ||
| 85 | * further action with regard to the KeyEvent; <code>false</code> | ||
| 86 | * otherwise | ||
| 87 | * @see KeyboardFocusManager#redispatchEvent | ||
| 88 | */ | ||
| 89 | boolean dispatchKeyEvent(KeyEvent e); | ||
| 90 | } | ||