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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) {}
}