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

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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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package java.awt.dnd;

/**

 * An abstract adapter class for receiving drag source 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>DragSourceEvent</code> listener

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

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

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

 * all, so you only have to define methods for events you care about.)

 * <p>

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

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

 * a drop site, when the drop action changes, and when the drag ends, the

 * relevant method in the listener object is invoked, and the

 * <code>DragSourceEvent</code> is passed to it.

 * <p>

 * The drop site is <i>associated with the previous <code>dragEnter()</code>

 * invocation</i> if the latest invocation of <code>dragEnter()</code> on this

 * adapter corresponds to that drop site and is not followed by a

 * <code>dragExit()</code> invocation on this adapter.

 *

 * @see DragSourceEvent

 * @see DragSourceListener

 * @see DragSourceMotionListener

 *

 * @author David Mendenhall

 * @since 1.4

 */

public abstract class DragSourceAdapter

    implements DragSourceListener, DragSourceMotionListener {

    /**

     * Called as the cursor's hotspot enters a platform-dependent drop site.

     * This method is invoked when all the following conditions are true:

     * <UL>

     * <LI>The cursor's hotspot enters the operable part of

     * a platform-dependent drop site.

     * <LI>The drop site is active.

     * <LI>The drop site accepts the drag.

     * </UL>

     *

     * @param dsde the <code>DragSourceDragEvent</code>

     */

    public void dragEnter(DragSourceDragEvent dsde) {}

    /**

     * Called as the cursor's hotspot moves over a platform-dependent drop site.

     * This method is invoked when all the following conditions are true:

     * <UL>

     * <LI>The cursor's hotspot has moved, but still intersects the

     * operable part of the drop site associated with the previous

     * dragEnter() invocation.

     * <LI>The drop site is still active.

     * <LI>The drop site accepts the drag.

     * </UL>

     *

     * @param dsde the <code>DragSourceDragEvent</code>

     */

    public void dragOver(DragSourceDragEvent dsde) {}

    /**

     * Called whenever the mouse is moved during a drag operation.

     *

     * @param dsde the <code>DragSourceDragEvent</code>

     */

    public void dragMouseMoved(DragSourceDragEvent dsde) {}

    /**

     * Called when the user has modified the drop gesture.

     * This method is invoked when the state of the input

     * device(s) that the user is interacting with changes.

     * Such devices are typically the mouse buttons or keyboard

     * modifiers that the user is interacting with.

     *

     * @param dsde the <code>DragSourceDragEvent</code>

     */

    public void dropActionChanged(DragSourceDragEvent dsde) {}

    /**

     * Called as the cursor's hotspot exits a platform-dependent drop site.

     * This method is invoked when any of the following conditions are true:

     * <UL>

     * <LI>The cursor's hotspot no longer intersects the operable part

     * of the drop site associated with the previous dragEnter() invocation.

     * </UL>

     * OR

     * <UL>

     * <LI>The drop site associated with the previous dragEnter() invocation

     * is no longer active.

     * </UL>

     * OR

     * <UL>

     * <LI> The drop site associated with the previous dragEnter() invocation

     * has rejected the drag.

     * </UL>

     *

     * @param dse the <code>DragSourceEvent</code>

     */

    public void dragExit(DragSourceEvent dse) {}

    /**

     * This method is invoked to signify that the Drag and Drop

     * operation is complete. The getDropSuccess() method of

     * the <code>DragSourceDropEvent</code> can be used to

     * determine the termination state. The getDropAction() method

     * returns the operation that the drop site selected

     * to apply to the Drop operation. Once this method is complete, the

     * current <code>DragSourceContext</code> and

     * associated resources become invalid.

     *

     * @param dsde the <code>DragSourceDropEvent</code>

     */

    public void dragDropEnd(DragSourceDropEvent dsde) {}

}