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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * particular file as subject to the "Classpath" exception as provided

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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * accompanied this code).

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 * 2 along with this work; if not, write to the Free Software Foundation,

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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.

 * <p>

 * Extend this class to create a <code>DropTargetEvent</code> listener

 * and override the methods for the events of interest. (If you implement the

 * <code>DropTargetListener</code> interface, you have to define all of

 * the methods in it. This abstract class defines a null implementation for

 * every method except <code>drop(DropTargetDropEvent)</code>, so you only have

 * to define methods for events you care about.) You must provide an

 * implementation for at least <code>drop(DropTargetDropEvent)</code>. 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.

 * <p>

 * Create a listener object using the extended class and then register it with

 * a <code>DropTarget</code>. When the drag enters, moves over, or exits

 * the operable part of the drop site for that <code>DropTarget</code>, when

 * the drop action changes, and when the drop occurs, the relevant method in

 * the listener object is invoked, and the <code>DropTargetEvent</code> is

 * passed to it.

 * <p>

 * The operable part of the drop site for the <code>DropTarget</code> is

 * the part of the associated <code>Component</code>'s geometry that is not

 * obscured by an overlapping top-level window or by another

 * <code>Component</code> higher in the Z-order that has an associated active

 * <code>DropTarget</code>.

 * <p>

 * During the drag, the data associated with the current drag operation can be

 * retrieved by calling <code>getTransferable()</code> on

 * <code>DropTargetDragEvent</code> instances passed to the listener's

 * methods.

 * <p>

 * Note that <code>getTransferable()</code> on the

 * <code>DropTargetDragEvent</code> instance should only be called within the

 * respective listener's method and all the necessary data should be retrieved

 * from the returned <code>Transferable</code> 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 <code>DropTarget</code>

     * registered with this listener.

     *

     * @param dtde the <code>DropTargetDragEvent</code>

     */

    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 <code>DropTarget</code>

     * registered with this listener.

     *

     * @param dtde the <code>DropTargetDragEvent</code>

     */

    public void dragOver(DropTargetDragEvent dtde) {}

    /**

     * Called if the user has modified

     * the current drop gesture.

     *

     * @param dtde the <code>DropTargetDragEvent</code>

     */

    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

     * <code>DropTarget</code> registered with this listener.

     *

     * @param dte the <code>DropTargetEvent</code>

     */

    public void dragExit(DropTargetEvent dte) {}

}