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| 1 | +/* | |
| 2 | + * Copyright (c) 2001, 2003, 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.dnd; | |
| 27 | + | |
| 28 | +/** | |
| 29 | + * An abstract adapter class for receiving drop target events. The methods in | |
| 30 | + * this class are empty. This class exists only as a convenience for creating | |
| 31 | + * listener objects. | |
| 32 | + * <p> | |
| 33 | + * Extend this class to create a <code>DropTargetEvent</code> listener | |
| 34 | + * and override the methods for the events of interest. (If you implement the | |
| 35 | + * <code>DropTargetListener</code> interface, you have to define all of | |
| 36 | + * the methods in it. This abstract class defines a null implementation for | |
| 37 | + * every method except <code>drop(DropTargetDropEvent)</code>, so you only have | |
| 38 | + * to define methods for events you care about.) You must provide an | |
| 39 | + * implementation for at least <code>drop(DropTargetDropEvent)</code>. This | |
| 40 | + * method cannot have a null implementation because its specification requires | |
| 41 | + * that you either accept or reject the drop, and, if accepted, indicate | |
| 42 | + * whether the drop was successful. | |
| 43 | + * <p> | |
| 44 | + * Create a listener object using the extended class and then register it with | |
| 45 | + * a <code>DropTarget</code>. When the drag enters, moves over, or exits | |
| 46 | + * the operable part of the drop site for that <code>DropTarget</code>, when | |
| 47 | + * the drop action changes, and when the drop occurs, the relevant method in | |
| 48 | + * the listener object is invoked, and the <code>DropTargetEvent</code> is | |
| 49 | + * passed to it. | |
| 50 | + * <p> | |
| 51 | + * The operable part of the drop site for the <code>DropTarget</code> is | |
| 52 | + * the part of the associated <code>Component</code>'s geometry that is not | |
| 53 | + * obscured by an overlapping top-level window or by another | |
| 54 | + * <code>Component</code> higher in the Z-order that has an associated active | |
| 55 | + * <code>DropTarget</code>. | |
| 56 | + * <p> | |
| 57 | + * During the drag, the data associated with the current drag operation can be | |
| 58 | + * retrieved by calling <code>getTransferable()</code> on | |
| 59 | + * <code>DropTargetDragEvent</code> instances passed to the listener's | |
| 60 | + * methods. | |
| 61 | + * <p> | |
| 62 | + * Note that <code>getTransferable()</code> on the | |
| 63 | + * <code>DropTargetDragEvent</code> instance should only be called within the | |
| 64 | + * respective listener's method and all the necessary data should be retrieved | |
| 65 | + * from the returned <code>Transferable</code> before that method returns. | |
| 66 | + * | |
| 67 | + * @see DropTargetEvent | |
| 68 | + * @see DropTargetListener | |
| 69 | + * | |
| 70 | + * @author David Mendenhall | |
| 71 | + * @since 1.4 | |
| 72 | + */ | |
| 73 | +public abstract class DropTargetAdapter implements DropTargetListener { | |
| 74 | + | |
| 75 | + /** | |
| 76 | + * Called while a drag operation is ongoing, when the mouse pointer enters | |
| 77 | + * the operable part of the drop site for the <code>DropTarget</code> | |
| 78 | + * registered with this listener. | |
| 79 | + * | |
| 80 | + * @param dtde the <code>DropTargetDragEvent</code> | |
| 81 | + */ | |
| 82 | + public void dragEnter(DropTargetDragEvent dtde) {} | |
| 83 | + | |
| 84 | + /** | |
| 85 | + * Called when a drag operation is ongoing, while the mouse pointer is still | |
| 86 | + * over the operable part of the drop site for the <code>DropTarget</code> | |
| 87 | + * registered with this listener. | |
| 88 | + * | |
| 89 | + * @param dtde the <code>DropTargetDragEvent</code> | |
| 90 | + */ | |
| 91 | + public void dragOver(DropTargetDragEvent dtde) {} | |
| 92 | + | |
| 93 | + /** | |
| 94 | + * Called if the user has modified | |
| 95 | + * the current drop gesture. | |
| 96 | + * | |
| 97 | + * @param dtde the <code>DropTargetDragEvent</code> | |
| 98 | + */ | |
| 99 | + public void dropActionChanged(DropTargetDragEvent dtde) {} | |
| 100 | + | |
| 101 | + /** | |
| 102 | + * Called while a drag operation is ongoing, when the mouse pointer has | |
| 103 | + * exited the operable part of the drop site for the | |
| 104 | + * <code>DropTarget</code> registered with this listener. | |
| 105 | + * | |
| 106 | + * @param dte the <code>DropTargetEvent</code> | |
| 107 | + */ | |
| 108 | + public void dragExit(DropTargetEvent dte) {} | |
| 109 | +} | |