J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2001-2003 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any 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 | } |