DropTargetDropEvent


1   /*
2    * @(#)DropTargetDropEvent.java 1.28 04/05/05
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package java.awt.dnd;
9   
10  import java.awt.Point  ;
11  
12  import java.awt.datatransfer.DataFlavor  ;
13  import java.awt.datatransfer.Transferable  ;
14  
15  import java.util.List  ;
16  
17  /**
18   * The <code>DropTargetDropEvent</code> is delivered 
19   * via the <code>DropTargetListener</code> drop() method. 
20   * <p>
21   * The <code>DropTargetDropEvent</code> reports the <i>source drop actions</i>
22   * and the <i>user drop action</i> that reflect the current state of the
23   * drag-and-drop operation. 
24   * <p>
25   * <i>Source drop actions</i> is a bitwise mask of <code>DnDConstants</code>
26   * that represents the set of drop actions supported by the drag source for 
27   * this drag-and-drop operation.
28   * <p>
29   * <i>User drop action</i> depends on the drop actions supported by the drag
30   * source and the drop action selected by the user. The user can select a drop
31   * action by pressing modifier keys during the drag operation: 
32   * <pre> 
33   *   Ctrl + Shift -> ACTION_LINK
34   *   Ctrl         -> ACTION_COPY
35   *   Shift        -> ACTION_MOVE
36   * </pre> 
37   * If the user selects a drop action, the <i>user drop action</i> is one of 
38   * <code>DnDConstants</code> that represents the selected drop action if this
39   * drop action is supported by the drag source or
40   * <code>DnDConstants.ACTION_NONE</code> if this drop action is not supported 
41   * by the drag source.
42   * <p>
43   * If the user doesn't select a drop action, the set of
44   * <code>DnDConstants</code> that represents the set of drop actions supported
45   * by the drag source is searched for <code>DnDConstants.ACTION_MOVE</code>,
46   * then for <code>DnDConstants.ACTION_COPY</code>, then for
47   * <code>DnDConstants.ACTION_LINK</code> and the <i>user drop action</i> is the
48   * first constant found. If no constant is found the <i>user drop action</i>
49   * is <code>DnDConstants.ACTION_NONE</code>.
50   * 
51   * @version     1.28, 05/05/04
52   * @since 1.2
53   */
54  
55  public class DropTargetDropEvent extends DropTargetEvent   {
56  
57      private static final long serialVersionUID = -1721911170440459322L;
58  
59      /**
60       * Construct a <code>DropTargetDropEvent</code> given
61       * the <code>DropTargetContext</code> for this operation, 
62       * the location of the drag <code>Cursor</code>'s
63       * hotspot in the <code>Component</code>'s coordinates, 
64       * the currently
65       * selected user drop action, and the current set of
66       * actions supported by the source.
67       * By default, this constructor 
68       * assumes that the target is not in the same virtual machine as 
69       * the source; that is, {@link #isLocalTransfer()} will 
70       * return <code>false</code>.
71       * <P>
72       * @param dtc        The <code>DropTargetContext</code> for this operation
73       * @param cursorLocn The location of the "Drag" Cursor's 
74       * hotspot in <code>Component</code> coordinates
75       * @param dropAction the user drop action.
76       * @param srcActions the source drop actions.
77       * 
78       * @throws <code>NullPointerException</code> 
79       * if cursorLocn is <code>null</code>
80       * @throws <code>IllegalArgumentException</code> if dropAction is not one of
81       *         <code>DnDConstants</code>.
82       * @throws <code>IllegalArgumentException</code> if srcActions is not
83       *         a bitwise mask of <code>DnDConstants</code>.
84       * @throws <code>IllegalArgumentException</code> if dtc is <code>null</code>.
85       */
86  
87      public DropTargetDropEvent(DropTargetContext   dtc, Point   cursorLocn, int dropAction, int srcActions)  {
88      super(dtc);
89  
90      if (cursorLocn == null) throw new NullPointerException  ("cursorLocn");
91  
92      if (dropAction != DnDConstants.ACTION_NONE &&
93          dropAction != DnDConstants.ACTION_COPY &&
94          dropAction != DnDConstants.ACTION_MOVE &&
95          dropAction != DnDConstants.ACTION_LINK
96      ) throw new IllegalArgumentException  ("dropAction = " + dropAction);
97  
98      if ((srcActions & ~(DnDConstants.ACTION_COPY_OR_MOVE | DnDConstants.ACTION_LINK)) != 0) throw new IllegalArgumentException  ("srcActions");
99  
100     location        = cursorLocn;
101     actions         = srcActions;
102     this.dropAction = dropAction;
103     }
104 
105     /**
106      * Construct a <code>DropTargetEvent</code> given the 
107      * <code>DropTargetContext</code> for this operation,
108      * the location of the drag <code>Cursor</code>'s hotspot 
109      * in the <code>Component</code>'s 
110      * coordinates, the currently selected user drop action, 
111      * the current set of actions supported by the source,
112      * and a <code>boolean</code> indicating if the source is in the same JVM
113      * as the target.
114      * <P>
115      * @param dtc        The DropTargetContext for this operation
116      * @param cursorLocn The location of the "Drag" Cursor's 
117      * hotspot in Component's coordinates
118      * @param dropAction the user drop action.
119      * @param srcActions the source drop actions.
120      * @param isLocal  True if the source is in the same JVM as the target
121      *
122      * @throws <code>NullPointerException</code> if cursorLocn is
123      *         <code>null</code> 
124      * @throws <code>IllegalArgumentException</code> if dropAction is not one of
125      *         <code>DnDConstants</code>.
126      * @throws <code>IllegalArgumentException</code> if srcActions is not
127      *         a bitwise mask of <code>DnDConstants</code>.
128      * @throws <code>IllegalArgumentException</code> if dtc is <code>null</code>.
129      */
130 
131     public DropTargetDropEvent(DropTargetContext   dtc, Point   cursorLocn, int dropAction, int srcActions, boolean isLocal)  {
132     this(dtc, cursorLocn, dropAction, srcActions);
133 
134     isLocalTx = isLocal;
135     }
136 
137     /**
138      * This method returns a <code>Point</code>
139      * indicating the <code>Cursor</code>'s current
140      * location in the <code>Component</code>'s coordinates.
141      * <P>
142      * @return the current <code>Cursor</code> location in Component's coords.
143      */
144 
145     public Point   getLocation() {
146     return location;
147     }
148 
149 
150     /**
151      * This method returns the current DataFlavors.
152      * <P>
153      * @return current DataFlavors
154      */
155 
156     public DataFlavor  [] getCurrentDataFlavors() {
157     return getDropTargetContext().getCurrentDataFlavors();
158     }
159 
160     /**
161      * This method returns the currently available
162      * <code>DataFlavor</code>s as a <code>java.util.List</code>.
163      * <P>
164      * @return the currently available DataFlavors as a java.util.List
165      */
166 
167     public List  <DataFlavor  > getCurrentDataFlavorsAsList() {
168     return getDropTargetContext().getCurrentDataFlavorsAsList();
169     }
170 
171     /**
172      * This method returns a <code>boolean</code> indicating if the
173      * specified <code>DataFlavor</code> is available
174      * from the source.
175      * <P>
176      * @param df the <code>DataFlavor</code> to test
177      * <P>
178      * @return if the DataFlavor specified is available from the source
179      */
180 
181     public boolean isDataFlavorSupported(DataFlavor   df) {
182     return getDropTargetContext().isDataFlavorSupported(df);
183     }
184 
185     /**
186      * This method returns the source drop actions.
187      * 
188      * @return the source drop actions.
189      */
190     public int getSourceActions() { return actions; }
191 
192     /**
193      * This method returns the user drop action.
194      * 
195      * @return the user drop actions.
196      */
197     public int getDropAction() { return dropAction; }
198 
199     /**
200      * This method returns the <code>Transferable</code> object 
201      * associated with the drop.
202      * <P>
203      * @return the <code>Transferable</code> associated with the drop
204      */
205 
206     public Transferable   getTransferable() {
207     return getDropTargetContext().getTransferable();
208     }
209 
210     /**
211      * accept the drop, using the specified action.
212      * <P>
213      * @param dropAction the specified action
214      */
215 
216     public void acceptDrop(int dropAction) {
217     getDropTargetContext().acceptDrop(dropAction);
218     }
219 
220     /**
221      * reject the Drop.
222      */
223 
224     public void rejectDrop() {
225     getDropTargetContext().rejectDrop();
226     }
227 
228     /**
229      * This method notifies the <code>DragSource</code> 
230      * that the drop transfer(s) are completed.
231      * <P>
232      * @param success a <code>boolean</code> indicating that the drop transfer(s) are completed.
233      */
234 
235     public void dropComplete(boolean success) {
236     getDropTargetContext().dropComplete(success);
237     }
238     
239     /**
240      * This method returns an <code>int</code> indicating if
241      * the source is in the same JVM as the target.
242      * <P>
243      * @return if the Source is in the same JVM
244      */
245 
246     public boolean isLocalTransfer() {
247     return isLocalTx;
248     }
249 
250     /*
251      * fields
252      */
253 
254     static final private Point    zero     = new Point  (0,0);
255 
256     /**
257      * The location of the drag cursor's hotspot in Component coordinates.
258      *
259      * @serial
260      */
261     private Point         location   = zero;
262 
263     /**
264      * The source drop actions.
265      *
266      * @serial
267      */
268     private int         actions    = DnDConstants.ACTION_NONE;
269 
270     /**
271      * The user drop action.
272      *
273      * @serial
274      */
275     private int         dropAction = DnDConstants.ACTION_NONE;
276 
277     /**
278      * <code>true</code> if the source is in the same JVM as the target.
279      *
280      * @serial
281      */
282     private boolean         isLocalTx = false;
283 }
284
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