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Java > Open Source Codes > org > eclipse > swt > dnd > DragSourceListener


1 /*******************************************************************************
2  * Copyright (c) 2000, 2003 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Eclipse Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/epl-v10.html
7  *
8  * Contributors:
9  * IBM Corporation - initial API and implementation
10  *******************************************************************************/
11 package org.eclipse.swt.dnd;
12
13 import org.eclipse.swt.internal.SWTEventListener;
14
15 /**
16  * The <code>DragSourceListener</code> class provides event notification to the application for DragSource events.
17  *
18  * <p>When the user drops data on a <code>DropTarget</code>, the application which defines the <code>DragSource</code>
19  * must provide the dropped data by implementing <code>dragSetData</code>. In the dragSetData, the application
20  * must support all the data types that were specified in the DragSource#setTransfer method.</p>
21  *
22  * <p>After the drop has completed successfully or has been aborted, the application which defines the
23  * <code>DragSource</code> is required to take the appropriate cleanup action. In the case of a successful
24  * <b>move</b> operation, the application must remove the data that was transferred.</p>
25  *
26  */
27 public interface DragSourceListener extends SWTEventListener {
28
29 /**
30  * The user has begun the actions required to drag the widget. This event gives the application
31  * the chance to decide if a drag should be started.
32  *
33  * <p>The following fields in the DragSourceEvent apply:
34  * <ul>
35  * <li>(in)widget
36  * <li>(in)time
37  * <li>(in,out)doit
38  * </ul></p>
39  *
40  * @param event the information associated with the drag start event
41  *
42  * @see DragSourceEvent
43  */
44 public void dragStart(DragSourceEvent event);
45
46 /**
47  * The data is required from the drag source.
48  *
49  * <p>The following fields in the DragSourceEvent apply:
50  * <ul>
51  * <li>(in)widget
52  * <li>(in)time
53  * <li>(in)dataType - the type of data requested.
54  * <li>(out)data - the application inserts the actual data here (must match the dataType)
55  * </ul></p>
56  *
57  * @param event the information associated with the drag set data event
58  *
59  * @see DragSourceEvent
60  */
61 public void dragSetData(DragSourceEvent event);
62
63 /**
64  * The drop has successfully completed(mouse up over a valid target) or has been terminated (such as hitting
65  * the ESC key). Perform cleanup such as removing data from the source side on a successful move operation.
66  *
67  * <p>The following fields in the DragSourceEvent apply:
68  * <ul>
69  * <li>(in)widget
70  * <li>(in)time
71  * <li>(in)doit
72  * <li>(in)detail
73  * </ul></p>
74  *
75  * @param event the information associated with the drag finished event
76  *
77  * @see DragSourceEvent
78  */
79 public void dragFinished(DragSourceEvent event);
80 }
81
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