/* * Copyright (c) 2001, 2003, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.awt.dnd; /** * An abstract adapter class for receiving drop target events. The methods in * this class are empty. This class exists only as a convenience for creating * listener objects. *

* Extend this class to create a DropTargetEvent listener * and override the methods for the events of interest. (If you implement the * DropTargetListener interface, you have to define all of * the methods in it. This abstract class defines a null implementation for * every method except drop(DropTargetDropEvent), so you only have * to define methods for events you care about.) You must provide an * implementation for at least drop(DropTargetDropEvent). This * method cannot have a null implementation because its specification requires * that you either accept or reject the drop, and, if accepted, indicate * whether the drop was successful. *

* Create a listener object using the extended class and then register it with * a DropTarget. When the drag enters, moves over, or exits * the operable part of the drop site for that DropTarget, when * the drop action changes, and when the drop occurs, the relevant method in * the listener object is invoked, and the DropTargetEvent is * passed to it. *

* The operable part of the drop site for the DropTarget is * the part of the associated Component's geometry that is not * obscured by an overlapping top-level window or by another * Component higher in the Z-order that has an associated active * DropTarget. *

* During the drag, the data associated with the current drag operation can be * retrieved by calling getTransferable() on * DropTargetDragEvent instances passed to the listener's * methods. *

* Note that getTransferable() on the * DropTargetDragEvent instance should only be called within the * respective listener's method and all the necessary data should be retrieved * from the returned Transferable before that method returns. * * @see DropTargetEvent * @see DropTargetListener * * @author David Mendenhall * @since 1.4 */ public abstract class DropTargetAdapter implements DropTargetListener { /** * Called while a drag operation is ongoing, when the mouse pointer enters * the operable part of the drop site for the DropTarget * registered with this listener. * * @param dtde the DropTargetDragEvent */ public void dragEnter(DropTargetDragEvent dtde) {} /** * Called when a drag operation is ongoing, while the mouse pointer is still * over the operable part of the drop site for the DropTarget * registered with this listener. * * @param dtde the DropTargetDragEvent */ public void dragOver(DropTargetDragEvent dtde) {} /** * Called if the user has modified * the current drop gesture. * * @param dtde the DropTargetDragEvent */ public void dropActionChanged(DropTargetDragEvent dtde) {} /** * Called while a drag operation is ongoing, when the mouse pointer has * exited the operable part of the drop site for the * DropTarget registered with this listener. * * @param dte the DropTargetEvent */ public void dragExit(DropTargetEvent dte) {} }