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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.


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.

Author:David Mendenhall
See Also:
Since:1.4
/**
 * 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 DropTarget
registered with this listener.

Params:
  • dtde – the DropTargetDragEvent
/**
     * 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 DropTarget
registered with this listener.

Params:
  • dtde – the DropTargetDragEvent
/**
     * 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.

Params:
  • dtde – the DropTargetDragEvent
/**
     * 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
DropTarget registered with this listener.

Params:
  • dte – the DropTargetEvent
/**
     * 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) {}
}