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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.

 Extend this class to create a DragSourceEvent listener and override the methods for the events of interest. (If you implement the DragSourceListener 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.) 
 Create a listener object using the extended class and then register it with a DragSource. 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 DragSourceEvent is passed to it. 

The drop site is associated with the previous dragEnter() invocation if the latest invocation of dragEnter() on this adapter corresponds to that drop site and is not followed by a dragExit() invocation on this adapter. 
Author:David Mendenhall
See Also:
Since:1.4
/**
 * 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} listener
 * and override the methods for the events of interest. (If you implement the
 * {@code DragSourceListener} 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}. 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} is passed to it.
 * <p>
 * The drop site is <i>associated with the previous {@code dragEnter()}
 * invocation</i> if the latest invocation of {@code dragEnter()} on this
 * adapter corresponds to that drop site and is not followed by a
 * {@code dragExit()} 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:

    

  • The cursor's hotspot enters the operable part of
a platform-dependent drop site.

  • The drop site is active.

  • The drop site accepts the drag.



Params:
  • dsde – the DragSourceDragEvent
/**
     * 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}
     */
    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:

    

  • The cursor's hotspot has moved, but still intersects the
operable part of the drop site associated with the previous
dragEnter() invocation.

  • The drop site is still active.

  • The drop site accepts the drag.



Params:
  • dsde – the DragSourceDragEvent
/**
     * 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}
     */
    public void dragOver(DragSourceDragEvent dsde) {}

    
Called whenever the mouse is moved during a drag operation.

Params:
  • dsde – the DragSourceDragEvent
/**
     * Called whenever the mouse is moved during a drag operation.
     *
     * @param dsde the {@code DragSourceDragEvent}
     */
    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.

Params:
  • dsde – the DragSourceDragEvent
/**
     * 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}
     */
    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:

    

  • The cursor's hotspot no longer intersects the operable part
of the drop site associated with the previous dragEnter() invocation.


OR

    

  • The drop site associated with the previous dragEnter() invocation
is no longer active.


OR

    

  •  The drop site associated with the previous dragEnter() invocation
has rejected the drag.



Params:
  • dse – the DragSourceEvent
/**
     * 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}
     */
    public void dragExit(DragSourceEvent dse) {}

    
This method is invoked to signify that the Drag and Drop operation is complete. The getDropSuccess() method of the DragSourceDropEvent 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 DragSourceContext and associated resources become invalid. 
Params:
  • dsde – the DragSourceDropEvent
/**
     * This method is invoked to signify that the Drag and Drop
     * operation is complete. The getDropSuccess() method of
     * the {@code DragSourceDropEvent} 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} and
     * associated resources become invalid.
     *
     * @param dsde the {@code DragSourceDropEvent}
     */
    public void dragDropEnd(DragSourceDropEvent dsde) {}
}