Package edu.cnu.mdi.transfer

Interface PaletteDragSupport.PaletteDragSource

Enclosing class:

PaletteDragSupport

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public static interface PaletteDragSupport.PaletteDragSource

Supplies the drag payload and receives end-of-drag notification.

Implement this interface (typically as a lambda) and pass it to the PaletteDragSupport constructor. The two methods correspond to the two moments the palette cares about: "what are we dragging?" and "the drag is over, clean up".

Method Summary

Modifier and Type	Method	Description
Transferable	createTransferable(Point dragOrigin)	Return the Transferable payload for a drag starting at dragOrigin, or null to cancel the drag.
default void	onDragEnd()	Called on the EDT after every drag attempt ends — success, failure, or cancellation.

Method Details

createTransferable

Transferable createTransferable(Point dragOrigin)

Return the Transferable payload for a drag starting at dragOrigin, or null to cancel the drag.

Called on the EDT from the DragSource gesture recogniser. Returning null suppresses the drag entirely — no cursor change, no drop target notification. This is the correct way to reject a drag that starts on a non-draggable area (e.g. a label column in a table).

Parameters:

dragOrigin - the point, in the source component's coordinate space, where the drag gesture began

Returns:

the payload to carry, or null to cancel

onDragEnd

default void onDragEnd()

Called on the EDT after every drag attempt ends — success, failure, or cancellation.

The default implementation is a no-op. Override to clear a selection highlight or reset any transient visual state.