| /* |
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| |
| /** |
| * Drag and Drop is a direct manipulation gesture found in many Graphical User |
| * Interface systems that provides a mechanism to transfer information between |
| * two entities logically associated with presentation elements in the GUI. |
| * Normally driven by a physical gesture of a human user using an appropriate |
| * input device, Drag and Drop provides both a mechanism to enable continuous |
| * feedback regarding the possible outcome of any subsequent data transfer to |
| * the user during navigation over the presentation elements in the GUI, and the |
| * facilities to provide for any subsequent data negotiation and transfer. |
| * <p> |
| * This package defines the classes and interfaces necessary to perform Drag and |
| * Drop operations in Java. It defines classes for the drag-source and the |
| * drop-target, as well as events for transferring the data being dragged. This |
| * package also provides a means for giving visual feedback to the user |
| * throughout the duration of the Drag and Drop operation. |
| * <p> |
| * A typical Drag and Drop operation can be decomposed into the following states |
| * (not entirely sequentially): |
| * <ul> |
| * <li>A {@code DragSource} comes into existence, associated with some |
| * presentation element ({@code Component}) in the GUI, to initiate a Drag |
| * and Drop of some potentially {@code Transferable} data.</li> |
| * <li>1 or more {@code DropTarget}(s) come into/go out of existence, |
| * associated with presentation elements in the GUI (Components), |
| * potentially capable of consuming {@code Transferable} data types.</li> |
| * <li>A {@code DragGestureRecognizer} is obtained from the |
| * {@code DragSource} and is associated with a {@code Component} in order to |
| * track and identify any Drag initiating gesture by the user over the |
| * {@code Component}.</li> |
| * <li>A user makes a Drag gesture over the {@code Component}, which the |
| * registered {@code DragGestureRecognizer} detects, and notifies its |
| * {@code DragGestureListener} of. |
| * <p> |
| * Note: Although this API consistently refers to the stimulus for a drag |
| * and drop operation being a physical gesture by a human user, this does |
| * not preclude a programmatically driven DnD operation given the |
| * appropriate implementation of a {@code DragSource}. This package |
| * contains the abstract class {@code MouseDragGestureRecognizer} for |
| * recognizing mouse device gestures. Other abstract subclasses may be |
| * provided by the platform to support other input devices or particular |
| * {@code Component} class semantics.</li> |
| * <li>The {@code DragGestureListener} causes the {@code DragSource} to |
| * initiate the Drag and Drop operation on behalf of the user, perhaps |
| * animating the GUI Cursor and/or rendering an {@code Image} of the item(s) |
| * that are the subject of the operation.</li> |
| * <li>As the user gestures navigate over {@code Component}(s) in the GUI |
| * with associated {@code DropTarget}(s), the {@code DragSource} receives |
| * notifications in order to provide "Drag Over" feedback effects, and the |
| * {@code DropTarget}(s) receive notifications in order to provide |
| * "Drag Under" feedback effects based upon the operation(s) supported and |
| * the data type(s) involved.</li> |
| * </ul> |
| * <p> |
| * The gesture itself moves a logical cursor across the GUI hierarchy, |
| * intersecting the geometry of GUI Component(s), possibly resulting in the |
| * logical "Drag" cursor entering, crossing, and subsequently leaving |
| * {@code Component}(s) and associated {@code DropTarget}(s). |
| * <p> |
| * The {@code DragSource} object manifests "Drag Over" feedback to the user, in |
| * the typical case by animating the GUI {@code Cursor} associated with the |
| * logical cursor. |
| * <p> |
| * {@code DropTarget} objects manifest "Drag Under" feedback to the user, in the |
| * typical case, by rendering animations into their associated GUI |
| * {@code Component}(s) under the GUI Cursor. |
| * <p> |
| * The determination of the feedback effects, and the ultimate success or |
| * failure of the data transfer, should one occur, is parameterized as follows: |
| * <ul> |
| * <li>By the transfer "operation" selected by the user, and supported by |
| * both the {@code DragSource} and {@code DropTarget}: Copy, Move or |
| * Reference(link).</li> |
| * <li>By the intersection of the set of data types provided by the |
| * {@code DragSource} and the set of data types comprehensible by the |
| * {@code DropTarget}.</li> |
| * <li>When the user terminates the drag operation, normally resulting in a |
| * successful Drop, both the {@code DragSource} and {@code DropTarget} |
| * receive notifications that include, and result in the type negotiation |
| * and transfer of, the information associated with the {@code DragSource} |
| * via a {@code Transferable} object.</li> |
| * </ul> |
| * |
| * @since 1.2 |
| */ |
| package java.awt.dnd; |
