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|  | <head><title></title></head> | 
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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</code> comes into existence, | 
|  | associated with some presentation | 
|  | element (<code>Component</code>) in the GUI, to initiate a Drag and Drop of | 
|  | some potentially <code>Transferable</code> data. | 
|  | <br><br> | 
|  | <LI>1 or more <code>DropTarget</code>(s) come into/go out of | 
|  | existence, associated | 
|  | with presentation elements in the GUI (Components), potentially | 
|  | capable of consuming <code>Transferable</code> data types. | 
|  | <br><br> | 
|  | <LI> A <code>DragGestureRecognizer</code> is | 
|  | obtained from the <code>DragSource</code> and is | 
|  | associated with a <code>Component</code> in order | 
|  | to track and identify any Drag | 
|  | initiating gesture by the user over the <code>Component</code>. | 
|  | <br><br> | 
|  | <LI> A user makes a Drag gesture over the <code>Component</code>, | 
|  | which the registered | 
|  | <code>DragGestureRecognizer</code> detects, and notifies its | 
|  | <code>DragGestureListener</code> 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</code>. This package | 
|  | contains the abstract class <code>MouseDragGestureRecognizer</code> for | 
|  | recognizing mouse device gestures. Other abstract subclasses may be | 
|  | provided by the platform to support other input devices or | 
|  | particular <code>Component</code> class semantics. | 
|  | <br><br> | 
|  | <LI> The <code>DragGestureListener</code> causes the | 
|  | <code>DragSource</code> to initiate the Drag | 
|  | and Drop operation on behalf of the user, perhaps animating the | 
|  | GUI Cursor and/or rendering an <code>Image</code> of the item(s) that are the | 
|  | subject of the operation. | 
|  | <br><br> | 
|  | <LI> As the user gestures navigate over <code>Component</code>(s) | 
|  | in the GUI with | 
|  | associated <code>DropTarget</code>(s), the <code>DragSource</code> | 
|  | receives notifications in order | 
|  | to provide "Drag Over" feedback effects, and the <code>DropTarget</code>(s) | 
|  | receive notifications in order to provide "Drag Under" feedback effects | 
|  | based upon the operation(s) supported and the data type(s) involved. | 
|  | </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</code>(s) and associated <code>DropTarget</code>(s). | 
|  | <P> | 
|  | The <code>DragSource</code> object manifests "Drag Over" feedback to the user, in the typical case by animating the GUI <code>Cursor</code> associated with the | 
|  | logical cursor. | 
|  | <P> | 
|  | <code>DropTarget</code> objects manifest "Drag Under" feedback to the user, in | 
|  | the typical case, by rendering animations into their associated GUI | 
|  | <code>Component</code>(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</code> and <code>DropTarget</code>: Copy, Move or Reference(link). | 
|  | <br><br> | 
|  | <LI> By the intersection of the set of data types provided by the | 
|  | <code>DragSource</code> and the set of data types comprehensible by the | 
|  | <code>DropTarget</code>. | 
|  | <br><br> | 
|  | <LI>When the user terminates the drag operation, normally resulting in a | 
|  | successful Drop, both the <code>DragSource</code> and <code>DropTarget</code> | 
|  | receive | 
|  | notifications that include, and result in the type negotiation and | 
|  | transfer of, the information associated with the <code>DragSource</code> via a | 
|  | <code>Transferable</code> object. | 
|  | </UL> | 
|  |  | 
|  | <!-- | 
|  | <h2>Package Specification</h2> | 
|  |  | 
|  | ##### FILL IN ANY SPECS NEEDED BY JAVA COMPATIBILITY KIT ##### | 
|  | <ul> | 
|  | <li><a href="">##### REFER TO ANY FRAMEMAKER SPECIFICATION HERE #####</a> | 
|  | </ul> | 
|  |  | 
|  | <h2>Related Documentation</h2> | 
|  |  | 
|  | For overviews, tutorials, examples, guides, and tool documentation, please see: | 
|  | <ul> | 
|  | <li><a href="">##### REFER TO NON-SPEC DOCUMENTATION HERE #####</a> | 
|  | </ul> | 
|  | --> | 
|  |  | 
|  | @since 1.2 | 
|  | </body> | 
|  | </html> |