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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 | } | ||