source: josm/trunk/src/org/openstreetmap/josm/gui/FileDrop.java@ 10536

Last change on this file since 10536 was 10212, checked in by Don-vip, 8 years ago

sonar - squid:S2221 - "Exception" should not be caught when not required by called methods
  • Property svn:eol-style set to native
File size: 24.8 KB
Line 
1/* code from: http://iharder.sourceforge.net/current/java/filedrop/
2 (public domain) with only very small additions */
3package org.openstreetmap.josm.gui;
4
5import java.awt.Color;
6import java.awt.Component;
7import java.awt.Container;
8import java.awt.datatransfer.DataFlavor;
9import java.awt.datatransfer.Transferable;
10import java.awt.datatransfer.UnsupportedFlavorException;
11import java.awt.dnd.DnDConstants;
12import java.awt.dnd.DropTarget;
13import java.awt.dnd.DropTargetDragEvent;
14import java.awt.dnd.DropTargetDropEvent;
15import java.awt.dnd.DropTargetEvent;
16import java.awt.dnd.DropTargetListener;
17import java.awt.dnd.InvalidDnDOperationException;
18import java.awt.event.HierarchyEvent;
19import java.awt.event.HierarchyListener;
20import java.io.BufferedReader;
21import java.io.File;
22import java.io.IOException;
23import java.io.Reader;
24import java.net.URI;
25import java.net.URISyntaxException;
26import java.util.ArrayList;
27import java.util.Arrays;
28import java.util.List;
29import java.util.TooManyListenersException;
30
31import javax.swing.BorderFactory;
32import javax.swing.JComponent;
33import javax.swing.border.Border;
34
35import org.openstreetmap.josm.Main;
36import org.openstreetmap.josm.actions.OpenFileAction;
37import org.openstreetmap.josm.gui.FileDrop.TransferableObject;
38
39// CHECKSTYLE.OFF: HideUtilityClassConstructor
40
41/**
42 * This class makes it easy to drag and drop files from the operating
43 * system to a Java program. Any {@link java.awt.Component} can be
44 * dropped onto, but only {@link javax.swing.JComponent}s will indicate
45 * the drop event with a changed border.
46 * <p>
47 * To use this class, construct a new <tt>FileDrop</tt> by passing
48 * it the target component and a <tt>Listener</tt> to receive notification
49 * when file(s) have been dropped. Here is an example:
50 * <p>
51 * <code>
52 * JPanel myPanel = new JPanel();
53 * new FileDrop( myPanel, new FileDrop.Listener()
54 * { public void filesDropped( java.io.File[] files )
55 * {
56 * // handle file drop
57 * ...
58 * } // end filesDropped
59 * }); // end FileDrop.Listener
60 * </code>
61 * <p>
62 * You can specify the border that will appear when files are being dragged by
63 * calling the constructor with a {@link javax.swing.border.Border}. Only
64 * <tt>JComponent</tt>s will show any indication with a border.
65 * <p>
66 * You can turn on some debugging features by passing a <tt>PrintStream</tt>
67 * object (such as <tt>System.out</tt>) into the full constructor. A <tt>null</tt>
68 * value will result in no extra debugging information being output.
69 *
70 * <p>I'm releasing this code into the Public Domain. Enjoy.
71 * </p>
72 * <p><em>Original author: Robert Harder, rharder@usa.net</em></p>
73 * <p>2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.</p>
74 *
75 * @author Robert Harder
76 * @author rharder@users.sf.net
77 * @version 1.0.1
78 * @since 1231
79 */
80public class FileDrop {
81
82 // CHECKSTYLE.ON: HideUtilityClassConstructor
83
84 private Border normalBorder;
85 private DropTargetListener dropListener;
86
87 // Default border color
88 private static Color defaultBorderColor = new Color(0f, 0f, 1f, 0.25f);
89
90 /**
91 * Constructor for JOSM file drop
92 * @param c The drop target
93 */
94 public FileDrop(final Component c) {
95 this(
96 c, // Drop target
97 BorderFactory.createMatteBorder(2, 2, 2, 2, defaultBorderColor), // Drag border
98 true, // Recursive
99 new FileDrop.Listener() {
100 @Override
101 public void filesDropped(File[] files) {
102 // start asynchronous loading of files
103 OpenFileAction.OpenFileTask task = new OpenFileAction.OpenFileTask(Arrays.asList(files), null);
104 task.setRecordHistory(true);
105 Main.worker.submit(task);
106 }
107 }
108 );
109 }
110
111 /**
112 * Full constructor with a specified border and debugging optionally turned on.
113 * With Debugging turned on, more status messages will be displayed to
114 * <tt>out</tt>. A common way to use this constructor is with
115 * <tt>System.out</tt> or <tt>System.err</tt>. A <tt>null</tt> value for
116 * the parameter <tt>out</tt> will result in no debugging output.
117 *
118 * @param c Component on which files will be dropped.
119 * @param dragBorder Border to use on <tt>JComponent</tt> when dragging occurs.
120 * @param recursive Recursively set children as drop targets.
121 * @param listener Listens for <tt>filesDropped</tt>.
122 */
123 public FileDrop(
124 final Component c,
125 final Border dragBorder,
126 final boolean recursive,
127 final Listener listener) {
128
129 // Make a drop listener
130 dropListener = new DropListener(listener, dragBorder, c);
131
132 // Make the component (and possibly children) drop targets
133 makeDropTarget(c, recursive);
134 }
135
136 // BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
137 private static final String ZERO_CHAR_STRING = Character.toString((char) 0);
138
139 private static File[] createFileArray(BufferedReader bReader) {
140 try {
141 List<File> list = new ArrayList<>();
142 String line;
143 while ((line = bReader.readLine()) != null) {
144 try {
145 // kde seems to append a 0 char to the end of the reader
146 if (ZERO_CHAR_STRING.equals(line)) {
147 continue;
148 }
149
150 list.add(new File(new URI(line)));
151 } catch (URISyntaxException ex) {
152 Main.warn("Error with " + line + ": " + ex.getMessage());
153 }
154 }
155
156 return list.toArray(new File[list.size()]);
157 } catch (IOException ex) {
158 Main.warn("FileDrop: IOException");
159 }
160 return new File[0];
161 }
162 // END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
163
164 private void makeDropTarget(final Component c, boolean recursive) {
165 // Make drop target
166 final DropTarget dt = new DropTarget();
167 try {
168 dt.addDropTargetListener(dropListener);
169 } catch (TooManyListenersException e) {
170 Main.error(e);
171 Main.warn("FileDrop: Drop will not work due to previous error. Do you have another listener attached?");
172 }
173
174 // Listen for hierarchy changes and remove the drop target when the parent gets cleared out.
175 c.addHierarchyListener(new HierarchyListener() {
176 @Override
177 public void hierarchyChanged(HierarchyEvent evt) {
178 Main.trace("FileDrop: Hierarchy changed.");
179 Component parent = c.getParent();
180 if (parent == null) {
181 c.setDropTarget(null);
182 Main.trace("FileDrop: Drop target cleared from component.");
183 } else {
184 new DropTarget(c, dropListener);
185 Main.trace("FileDrop: Drop target added to component.");
186 }
187 }
188 });
189 if (c.getParent() != null) {
190 new DropTarget(c, dropListener);
191 }
192
193 if (recursive && (c instanceof Container)) {
194 // Get the container
195 Container cont = (Container) c;
196
197 // Get it's components
198 Component[] comps = cont.getComponents();
199
200 // Set it's components as listeners also
201 for (Component comp : comps) {
202 makeDropTarget(comp, recursive);
203 }
204 }
205 }
206
207 /**
208 * Determines if the dragged data is a file list.
209 * @param evt the drag event
210 * @return {@code true} if the dragged data is a file list
211 */
212 private static boolean isDragOk(final DropTargetDragEvent evt) {
213 boolean ok = false;
214
215 // Get data flavors being dragged
216 DataFlavor[] flavors = evt.getCurrentDataFlavors();
217
218 // See if any of the flavors are a file list
219 int i = 0;
220 while (!ok && i < flavors.length) {
221 // BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
222 // Is the flavor a file list?
223 final DataFlavor curFlavor = flavors[i];
224 if (curFlavor.equals(DataFlavor.javaFileListFlavor) ||
225 curFlavor.isRepresentationClassReader()) {
226 ok = true;
227 }
228 // END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
229 i++;
230 }
231
232 // show data flavors
233 if (flavors.length == 0) {
234 Main.trace("FileDrop: no data flavors.");
235 }
236 for (i = 0; i < flavors.length; i++) {
237 Main.trace(flavors[i].toString());
238 }
239
240 return ok;
241 }
242
243 /**
244 * Removes the drag-and-drop hooks from the component and optionally
245 * from the all children. You should call this if you add and remove
246 * components after you've set up the drag-and-drop.
247 * This will recursively unregister all components contained within
248 * <var>c</var> if <var>c</var> is a {@link java.awt.Container}.
249 *
250 * @param c The component to unregister as a drop target
251 * @return {@code true} if at least one item has been removed, {@code false} otherwise
252 */
253 public static boolean remove(Component c) {
254 return remove(c, true);
255 }
256
257 /**
258 * Removes the drag-and-drop hooks from the component and optionally
259 * from the all children. You should call this if you add and remove
260 * components after you've set up the drag-and-drop.
261 *
262 * @param c The component to unregister
263 * @param recursive Recursively unregister components within a container
264 * @return {@code true} if at least one item has been removed, {@code false} otherwise
265 */
266 public static boolean remove(Component c, boolean recursive) {
267 Main.trace("FileDrop: Removing drag-and-drop hooks.");
268 c.setDropTarget(null);
269 if (recursive && (c instanceof Container)) {
270 for (Component comp : ((Container) c).getComponents()) {
271 remove(comp, recursive);
272 }
273 return true;
274 } else
275 return false;
276 }
277
278 /* ******** I N N E R I N T E R F A C E L I S T E N E R ******** */
279
280 private final class DropListener implements DropTargetListener {
281 private final Listener listener;
282 private final Border dragBorder;
283 private final Component c;
284
285 private DropListener(Listener listener, Border dragBorder, Component c) {
286 this.listener = listener;
287 this.dragBorder = dragBorder;
288 this.c = c;
289 }
290
291 @Override
292 public void dragEnter(DropTargetDragEvent evt) {
293 Main.trace("FileDrop: dragEnter event.");
294
295 // Is this an acceptable drag event?
296 if (isDragOk(evt)) {
297 // If it's a Swing component, set its border
298 if (c instanceof JComponent) {
299 JComponent jc = (JComponent) c;
300 normalBorder = jc.getBorder();
301 Main.trace("FileDrop: normal border saved.");
302 jc.setBorder(dragBorder);
303 Main.trace("FileDrop: drag border set.");
304 }
305
306 // Acknowledge that it's okay to enter
307 evt.acceptDrag(DnDConstants.ACTION_COPY);
308 Main.trace("FileDrop: event accepted.");
309 } else {
310 // Reject the drag event
311 evt.rejectDrag();
312 Main.trace("FileDrop: event rejected.");
313 }
314 }
315
316 @Override
317 public void dragOver(DropTargetDragEvent evt) {
318 // This is called continually as long as the mouse is over the drag target.
319 }
320
321 @Override
322 public void drop(DropTargetDropEvent evt) {
323 Main.trace("FileDrop: drop event.");
324 try {
325 // Get whatever was dropped
326 Transferable tr = evt.getTransferable();
327
328 // Is it a file list?
329 if (tr.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
330
331 // Say we'll take it.
332 evt.acceptDrop(DnDConstants.ACTION_COPY);
333 Main.trace("FileDrop: file list accepted.");
334
335 // Get a useful list
336 List<?> fileList = (List<?>) tr.getTransferData(DataFlavor.javaFileListFlavor);
337
338 // Convert list to array
339 final File[] files = fileList.toArray(new File[fileList.size()]);
340
341 // Alert listener to drop.
342 if (listener != null) {
343 listener.filesDropped(files);
344 }
345
346 // Mark that drop is completed.
347 evt.getDropTargetContext().dropComplete(true);
348 Main.trace("FileDrop: drop complete.");
349 } else {
350 // this section will check for a reader flavor.
351 // Thanks, Nathan!
352 // BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
353 DataFlavor[] flavors = tr.getTransferDataFlavors();
354 boolean handled = false;
355 for (DataFlavor flavor : flavors) {
356 if (flavor.isRepresentationClassReader()) {
357 // Say we'll take it.
358 evt.acceptDrop(DnDConstants.ACTION_COPY);
359 Main.trace("FileDrop: reader accepted.");
360
361 Reader reader = flavor.getReaderForText(tr);
362
363 BufferedReader br = new BufferedReader(reader);
364
365 if (listener != null) {
366 listener.filesDropped(createFileArray(br));
367 }
368
369 // Mark that drop is completed.
370 evt.getDropTargetContext().dropComplete(true);
371 Main.trace("FileDrop: drop complete.");
372 handled = true;
373 break;
374 }
375 }
376 if (!handled) {
377 Main.trace("FileDrop: not a file list or reader - abort.");
378 evt.rejectDrop();
379 }
380 // END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
381 }
382 } catch (IOException | UnsupportedFlavorException e) {
383 Main.warn("FileDrop: "+e.getClass().getSimpleName()+" - abort:");
384 Main.error(e);
385 try {
386 evt.rejectDrop();
387 } catch (InvalidDnDOperationException ex) {
388 // Catch InvalidDnDOperationException to fix #11259
389 Main.error(ex);
390 }
391 } finally {
392 // If it's a Swing component, reset its border
393 if (c instanceof JComponent) {
394 JComponent jc = (JComponent) c;
395 jc.setBorder(normalBorder);
396 Main.debug("FileDrop: normal border restored.");
397 }
398 }
399 }
400
401 @Override
402 public void dragExit(DropTargetEvent evt) {
403 Main.debug("FileDrop: dragExit event.");
404 // If it's a Swing component, reset its border
405 if (c instanceof JComponent) {
406 JComponent jc = (JComponent) c;
407 jc.setBorder(normalBorder);
408 Main.debug("FileDrop: normal border restored.");
409 }
410 }
411
412 @Override
413 public void dropActionChanged(DropTargetDragEvent evt) {
414 Main.debug("FileDrop: dropActionChanged event.");
415 // Is this an acceptable drag event?
416 if (isDragOk(evt)) {
417 evt.acceptDrag(DnDConstants.ACTION_COPY);
418 Main.debug("FileDrop: event accepted.");
419 } else {
420 evt.rejectDrag();
421 Main.debug("FileDrop: event rejected.");
422 }
423 }
424 }
425
426 /**
427 * Implement this inner interface to listen for when files are dropped. For example
428 * your class declaration may begin like this:
429 * <code>
430 * public class MyClass implements FileDrop.Listener
431 * ...
432 * public void filesDropped( java.io.File[] files )
433 * {
434 * ...
435 * } // end filesDropped
436 * ...
437 * </code>
438 */
439 public interface Listener {
440
441 /**
442 * This method is called when files have been successfully dropped.
443 *
444 * @param files An array of <tt>File</tt>s that were dropped.
445 */
446 void filesDropped(File[] files);
447 }
448
449 /* ******** I N N E R C L A S S ******** */
450
451 /**
452 * At last an easy way to encapsulate your custom objects for dragging and dropping
453 * in your Java programs!
454 * When you need to create a {@link java.awt.datatransfer.Transferable} object,
455 * use this class to wrap your object.
456 * For example:
457 * <pre><code>
458 * ...
459 * MyCoolClass myObj = new MyCoolClass();
460 * Transferable xfer = new TransferableObject( myObj );
461 * ...
462 * </code></pre>
463 * Or if you need to know when the data was actually dropped, like when you're
464 * moving data out of a list, say, you can use the {@link TransferableObject.Fetcher}
465 * inner class to return your object Just in Time.
466 * For example:
467 * <pre><code>
468 * ...
469 * final MyCoolClass myObj = new MyCoolClass();
470 *
471 * TransferableObject.Fetcher fetcher = new TransferableObject.Fetcher()
472 * { public Object getObject() { return myObj; }
473 * }; // end fetcher
474 *
475 * Transferable xfer = new TransferableObject( fetcher );
476 * ...
477 * </code></pre>
478 *
479 * The {@link java.awt.datatransfer.DataFlavor} associated with
480 * {@link TransferableObject} has the representation class
481 * <tt>net.iharder.dnd.TransferableObject.class</tt> and MIME type
482 * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
483 * This data flavor is accessible via the static
484 * {@link #DATA_FLAVOR} property.
485 *
486 *
487 * <p>I'm releasing this code into the Public Domain. Enjoy.</p>
488 *
489 * @author Robert Harder
490 * @author rob@iharder.net
491 * @version 1.2
492 */
493 public static class TransferableObject implements Transferable {
494
495 /**
496 * The MIME type for {@link #DATA_FLAVOR} is
497 * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
498 */
499 public static final String MIME_TYPE = "application/x-net.iharder.dnd.TransferableObject";
500
501 /**
502 * The default {@link java.awt.datatransfer.DataFlavor} for
503 * {@link TransferableObject} has the representation class
504 * <tt>net.iharder.dnd.TransferableObject.class</tt>
505 * and the MIME type
506 * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
507 */
508 public static final DataFlavor DATA_FLAVOR =
509 new DataFlavor(TransferableObject.class, MIME_TYPE);
510
511 private Fetcher fetcher;
512 private Object data;
513
514 private DataFlavor customFlavor;
515
516 /**
517 * Creates a new {@link TransferableObject} that wraps <var>data</var>.
518 * Along with the {@link #DATA_FLAVOR} associated with this class,
519 * this creates a custom data flavor with a representation class
520 * determined from <code>data.getClass()</code> and the MIME type
521 * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
522 *
523 * @param data The data to transfer
524 */
525 public TransferableObject(Object data) {
526 this.data = data;
527 this.customFlavor = new DataFlavor(data.getClass(), MIME_TYPE);
528 }
529
530 /**
531 * Creates a new {@link TransferableObject} that will return the
532 * object that is returned by <var>fetcher</var>.
533 * No custom data flavor is set other than the default
534 * {@link #DATA_FLAVOR}.
535 *
536 * @param fetcher The {@link Fetcher} that will return the data object
537 * @see Fetcher
538 */
539 public TransferableObject(Fetcher fetcher) {
540 this.fetcher = fetcher;
541 }
542
543 /**
544 * Creates a new {@link TransferableObject} that will return the
545 * object that is returned by <var>fetcher</var>.
546 * Along with the {@link #DATA_FLAVOR} associated with this class,
547 * this creates a custom data flavor with a representation class <var>dataClass</var>
548 * and the MIME type
549 * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
550 *
551 * @param dataClass The {@link java.lang.Class} to use in the custom data flavor
552 * @param fetcher The {@link Fetcher} that will return the data object
553 * @see Fetcher
554 */
555 public TransferableObject(Class<?> dataClass, Fetcher fetcher) {
556 this.fetcher = fetcher;
557 this.customFlavor = new DataFlavor(dataClass, MIME_TYPE);
558 }
559
560 /**
561 * Returns the custom {@link java.awt.datatransfer.DataFlavor} associated
562 * with the encapsulated object or <tt>null</tt> if the {@link Fetcher}
563 * constructor was used without passing a {@link java.lang.Class}.
564 *
565 * @return The custom data flavor for the encapsulated object
566 */
567 public DataFlavor getCustomDataFlavor() {
568 return customFlavor;
569 }
570
571 /* ******** T R A N S F E R A B L E M E T H O D S ******** */
572
573 /**
574 * Returns a two- or three-element array containing first
575 * the custom data flavor, if one was created in the constructors,
576 * second the default {@link #DATA_FLAVOR} associated with
577 * {@link TransferableObject}, and third the
578 * {@link java.awt.datatransfer.DataFlavor#stringFlavor}.
579 *
580 * @return An array of supported data flavors
581 */
582 @Override
583 public DataFlavor[] getTransferDataFlavors() {
584 if (customFlavor != null)
585 return new DataFlavor[] {
586 customFlavor,
587 DATA_FLAVOR,
588 DataFlavor.stringFlavor};
589 else
590 return new DataFlavor[] {
591 DATA_FLAVOR,
592 DataFlavor.stringFlavor};
593 }
594
595 /**
596 * Returns the data encapsulated in this {@link TransferableObject}.
597 * If the {@link Fetcher} constructor was used, then this is when
598 * the {@link Fetcher#getObject getObject()} method will be called.
599 * If the requested data flavor is not supported, then the
600 * {@link Fetcher#getObject getObject()} method will not be called.
601 *
602 * @param flavor The data flavor for the data to return
603 * @return The dropped data
604 */
605 @Override
606 public Object getTransferData(DataFlavor flavor)
607 throws UnsupportedFlavorException, IOException {
608 // Native object
609 if (flavor.equals(DATA_FLAVOR))
610 return fetcher == null ? data : fetcher.getObject();
611
612 // String
613 if (flavor.equals(DataFlavor.stringFlavor))
614 return fetcher == null ? data.toString() : fetcher.getObject().toString();
615
616 // We can't do anything else
617 throw new UnsupportedFlavorException(flavor);
618 }
619
620 /**
621 * Returns <tt>true</tt> if <var>flavor</var> is one of the supported
622 * flavors. Flavors are supported using the <code>equals(...)</code> method.
623 *
624 * @param flavor The data flavor to check
625 * @return Whether or not the flavor is supported
626 */
627 @Override
628 public boolean isDataFlavorSupported(DataFlavor flavor) {
629 // Native object
630 if (flavor.equals(DATA_FLAVOR))
631 return true;
632
633 // String
634 if (flavor.equals(DataFlavor.stringFlavor))
635 return true;
636
637 // We can't do anything else
638 return false;
639 }
640
641 /* ******** I N N E R I N T E R F A C E F E T C H E R ******** */
642
643 /**
644 * Instead of passing your data directly to the {@link TransferableObject}
645 * constructor, you may want to know exactly when your data was received
646 * in case you need to remove it from its source (or do anyting else to it).
647 * When the {@link #getTransferData getTransferData(...)} method is called
648 * on the {@link TransferableObject}, the {@link Fetcher}'s
649 * {@link #getObject getObject()} method will be called.
650 *
651 * @author Robert Harder
652 */
653 public interface Fetcher {
654 /**
655 * Return the object being encapsulated in the
656 * {@link TransferableObject}.
657 *
658 * @return The dropped object
659 */
660 Object getObject();
661 }
662 }
663}
Note: See TracBrowser for help on using the repository browser.