source: josm/trunk/src/org/openstreetmap/josm/gui/FileDrop.java@ 9733

Last change on this file since 9733 was 9249, checked in by Don-vip, 8 years ago

see #11390 - resolve last javadoc warnings with Java 8. "ant javadoc" now produces 0 warning \o/
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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.util.ArrayList;
26import java.util.Arrays;
27import java.util.List;
28import java.util.TooManyListenersException;
29
30import javax.swing.BorderFactory;
31import javax.swing.JComponent;
32import javax.swing.border.Border;
33
34import org.openstreetmap.josm.Main;
35import org.openstreetmap.josm.actions.OpenFileAction;
36import org.openstreetmap.josm.gui.FileDrop.TransferableObject;
37
38// CHECKSTYLE.OFF: HideUtilityClassConstructor
39
40/**
41 * This class makes it easy to drag and drop files from the operating
42 * system to a Java program. Any {@link java.awt.Component} can be
43 * dropped onto, but only {@link javax.swing.JComponent}s will indicate
44 * the drop event with a changed border.
45 * <p>
46 * To use this class, construct a new <tt>FileDrop</tt> by passing
47 * it the target component and a <tt>Listener</tt> to receive notification
48 * when file(s) have been dropped. Here is an example:
49 * <p>
50 * <code>
51 * JPanel myPanel = new JPanel();
52 * new FileDrop( myPanel, new FileDrop.Listener()
53 * { public void filesDropped( java.io.File[] files )
54 * {
55 * // handle file drop
56 * ...
57 * } // end filesDropped
58 * }); // end FileDrop.Listener
59 * </code>
60 * <p>
61 * You can specify the border that will appear when files are being dragged by
62 * calling the constructor with a {@link javax.swing.border.Border}. Only
63 * <tt>JComponent</tt>s will show any indication with a border.
64 * <p>
65 * You can turn on some debugging features by passing a <tt>PrintStream</tt>
66 * object (such as <tt>System.out</tt>) into the full constructor. A <tt>null</tt>
67 * value will result in no extra debugging information being output.
68 *
69 * <p>I'm releasing this code into the Public Domain. Enjoy.
70 * </p>
71 * <p><em>Original author: Robert Harder, rharder@usa.net</em></p>
72 * <p>2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.</p>
73 *
74 * @author Robert Harder
75 * @author rharder@users.sf.net
76 * @version 1.0.1
77 * @since 1231
78 */
79public class FileDrop {
80
81 // CHECKSTYLE.ON: HideUtilityClassConstructor
82
83 private Border normalBorder;
84 private DropTargetListener dropListener;
85
86 /** Discover if the running JVM is modern enough to have drag and drop. */
87 private static Boolean supportsDnD;
88
89 // Default border color
90 private static Color defaultBorderColor = new Color(0f, 0f, 1f, 0.25f);
91
92 /**
93 * Constructor for JOSM file drop
94 * @param c The drop target
95 */
96 public FileDrop(final Component c) {
97 this(
98 c, // Drop target
99 BorderFactory.createMatteBorder(2, 2, 2, 2, defaultBorderColor), // Drag border
100 true, // Recursive
101 new FileDrop.Listener() {
102 @Override
103 public void filesDropped(File[] files) {
104 // start asynchronous loading of files
105 OpenFileAction.OpenFileTask task = new OpenFileAction.OpenFileTask(Arrays.asList(files), null);
106 task.setRecordHistory(true);
107 Main.worker.submit(task);
108 }
109 }
110 );
111 }
112
113 /**
114 * Full constructor with a specified border and debugging optionally turned on.
115 * With Debugging turned on, more status messages will be displayed to
116 * <tt>out</tt>. A common way to use this constructor is with
117 * <tt>System.out</tt> or <tt>System.err</tt>. A <tt>null</tt> value for
118 * the parameter <tt>out</tt> will result in no debugging output.
119 *
120 * @param c Component on which files will be dropped.
121 * @param dragBorder Border to use on <tt>JComponent</tt> when dragging occurs.
122 * @param recursive Recursively set children as drop targets.
123 * @param listener Listens for <tt>filesDropped</tt>.
124 */
125 public FileDrop(
126 final Component c,
127 final Border dragBorder,
128 final boolean recursive,
129 final Listener listener) {
130
131 if (supportsDnD()) {
132 // Make a drop listener
133 dropListener = new DropListener(listener, dragBorder, c);
134
135 // Make the component (and possibly children) drop targets
136 makeDropTarget(c, recursive);
137 } else {
138 Main.info("FileDrop: Drag and drop is not supported with this JVM");
139 }
140 }
141
142 private static synchronized boolean supportsDnD() {
143 if (supportsDnD == null) {
144 boolean support = false;
145 try {
146 Class.forName("java.awt.dnd.DnDConstants");
147 support = true;
148 } catch (Exception e) {
149 support = false;
150 }
151 supportsDnD = support;
152 }
153 return supportsDnD.booleanValue();
154 }
155
156 // BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
157 private static final String ZERO_CHAR_STRING = Character.toString((char) 0);
158
159 private static File[] createFileArray(BufferedReader bReader) {
160 try {
161 List<File> list = new ArrayList<>();
162 String line = null;
163 while ((line = bReader.readLine()) != null) {
164 try {
165 // kde seems to append a 0 char to the end of the reader
166 if (ZERO_CHAR_STRING.equals(line)) {
167 continue;
168 }
169
170 File file = new File(new URI(line));
171 list.add(file);
172 } catch (Exception ex) {
173 Main.warn("Error with " + line + ": " + ex.getMessage());
174 }
175 }
176
177 return list.toArray(new File[list.size()]);
178 } catch (IOException ex) {
179 Main.warn("FileDrop: IOException");
180 }
181 return new File[0];
182 }
183 // END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
184
185 private void makeDropTarget(final Component c, boolean recursive) {
186 // Make drop target
187 final DropTarget dt = new DropTarget();
188 try {
189 dt.addDropTargetListener(dropListener);
190 } catch (TooManyListenersException e) {
191 Main.error(e);
192 Main.warn("FileDrop: Drop will not work due to previous error. Do you have another listener attached?");
193 }
194
195 // Listen for hierarchy changes and remove the drop target when the parent gets cleared out.
196 c.addHierarchyListener(new HierarchyListener() {
197 @Override
198 public void hierarchyChanged(HierarchyEvent evt) {
199 Main.trace("FileDrop: Hierarchy changed.");
200 Component parent = c.getParent();
201 if (parent == null) {
202 c.setDropTarget(null);
203 Main.trace("FileDrop: Drop target cleared from component.");
204 } else {
205 new DropTarget(c, dropListener);
206 Main.trace("FileDrop: Drop target added to component.");
207 }
208 }
209 });
210 if (c.getParent() != null) {
211 new DropTarget(c, dropListener);
212 }
213
214 if (recursive && (c instanceof Container)) {
215 // Get the container
216 Container cont = (Container) c;
217
218 // Get it's components
219 Component[] comps = cont.getComponents();
220
221 // Set it's components as listeners also
222 for (Component comp : comps) {
223 makeDropTarget(comp, recursive);
224 }
225 }
226 }
227
228 /**
229 * Determines if the dragged data is a file list.
230 * @param evt the drag event
231 * @return {@code true} if the dragged data is a file list
232 */
233 private static boolean isDragOk(final DropTargetDragEvent evt) {
234 boolean ok = false;
235
236 // Get data flavors being dragged
237 DataFlavor[] flavors = evt.getCurrentDataFlavors();
238
239 // See if any of the flavors are a file list
240 int i = 0;
241 while (!ok && i < flavors.length) {
242 // BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
243 // Is the flavor a file list?
244 final DataFlavor curFlavor = flavors[i];
245 if (curFlavor.equals(DataFlavor.javaFileListFlavor) ||
246 curFlavor.isRepresentationClassReader()) {
247 ok = true;
248 }
249 // END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
250 i++;
251 }
252
253 // show data flavors
254 if (flavors.length == 0) {
255 Main.trace("FileDrop: no data flavors.");
256 }
257 for (i = 0; i < flavors.length; i++) {
258 Main.trace(flavors[i].toString());
259 }
260
261 return ok;
262 }
263
264 /**
265 * Removes the drag-and-drop hooks from the component and optionally
266 * from the all children. You should call this if you add and remove
267 * components after you've set up the drag-and-drop.
268 * This will recursively unregister all components contained within
269 * <var>c</var> if <var>c</var> is a {@link java.awt.Container}.
270 *
271 * @param c The component to unregister as a drop target
272 * @return {@code true} if at least one item has been removed, {@code false} otherwise
273 */
274 public static boolean remove(Component c) {
275 return remove(c, true);
276 }
277
278 /**
279 * Removes the drag-and-drop hooks from the component and optionally
280 * from the all children. You should call this if you add and remove
281 * components after you've set up the drag-and-drop.
282 *
283 * @param c The component to unregister
284 * @param recursive Recursively unregister components within a container
285 * @return {@code true} if at least one item has been removed, {@code false} otherwise
286 */
287 public static boolean remove(Component c, boolean recursive) {
288 // Make sure we support dnd.
289 if (supportsDnD()) {
290 Main.trace("FileDrop: Removing drag-and-drop hooks.");
291 c.setDropTarget(null);
292 if (recursive && (c instanceof Container)) {
293 for (Component comp : ((Container) c).getComponents()) {
294 remove(comp, recursive);
295 }
296 return true;
297 } else
298 return false;
299 } else
300 return false;
301 }
302
303 /* ******** I N N E R I N T E R F A C E L I S T E N E R ******** */
304
305 private final class DropListener implements DropTargetListener {
306 private final Listener listener;
307 private final Border dragBorder;
308 private final Component c;
309
310 private DropListener(Listener listener, Border dragBorder, Component c) {
311 this.listener = listener;
312 this.dragBorder = dragBorder;
313 this.c = c;
314 }
315
316 @Override
317 public void dragEnter(DropTargetDragEvent evt) {
318 Main.trace("FileDrop: dragEnter event.");
319
320 // Is this an acceptable drag event?
321 if (isDragOk(evt)) {
322 // If it's a Swing component, set its border
323 if (c instanceof JComponent) {
324 JComponent jc = (JComponent) c;
325 normalBorder = jc.getBorder();
326 Main.trace("FileDrop: normal border saved.");
327 jc.setBorder(dragBorder);
328 Main.trace("FileDrop: drag border set.");
329 }
330
331 // Acknowledge that it's okay to enter
332 evt.acceptDrag(DnDConstants.ACTION_COPY);
333 Main.trace("FileDrop: event accepted.");
334 } else {
335 // Reject the drag event
336 evt.rejectDrag();
337 Main.trace("FileDrop: event rejected.");
338 }
339 }
340
341 @Override
342 public void dragOver(DropTargetDragEvent evt) {
343 // This is called continually as long as the mouse is over the drag target.
344 }
345
346 @Override
347 public void drop(DropTargetDropEvent evt) {
348 Main.trace("FileDrop: drop event.");
349 try {
350 // Get whatever was dropped
351 Transferable tr = evt.getTransferable();
352
353 // Is it a file list?
354 if (tr.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
355
356 // Say we'll take it.
357 evt.acceptDrop(DnDConstants.ACTION_COPY);
358 Main.trace("FileDrop: file list accepted.");
359
360 // Get a useful list
361 List<?> fileList = (List<?>) tr.getTransferData(DataFlavor.javaFileListFlavor);
362
363 // Convert list to array
364 final File[] files = fileList.toArray(new File[fileList.size()]);
365
366 // Alert listener to drop.
367 if (listener != null) {
368 listener.filesDropped(files);
369 }
370
371 // Mark that drop is completed.
372 evt.getDropTargetContext().dropComplete(true);
373 Main.trace("FileDrop: drop complete.");
374 } else {
375 // this section will check for a reader flavor.
376 // Thanks, Nathan!
377 // BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
378 DataFlavor[] flavors = tr.getTransferDataFlavors();
379 boolean handled = false;
380 for (DataFlavor flavor : flavors) {
381 if (flavor.isRepresentationClassReader()) {
382 // Say we'll take it.
383 evt.acceptDrop(DnDConstants.ACTION_COPY);
384 Main.trace("FileDrop: reader accepted.");
385
386 Reader reader = flavor.getReaderForText(tr);
387
388 BufferedReader br = new BufferedReader(reader);
389
390 if (listener != null) {
391 listener.filesDropped(createFileArray(br));
392 }
393
394 // Mark that drop is completed.
395 evt.getDropTargetContext().dropComplete(true);
396 Main.trace("FileDrop: drop complete.");
397 handled = true;
398 break;
399 }
400 }
401 if (!handled) {
402 Main.trace("FileDrop: not a file list or reader - abort.");
403 evt.rejectDrop();
404 }
405 // END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
406 }
407 } catch (IOException | UnsupportedFlavorException e) {
408 Main.warn("FileDrop: "+e.getClass().getSimpleName()+" - abort:");
409 Main.error(e);
410 try {
411 evt.rejectDrop();
412 } catch (InvalidDnDOperationException ex) {
413 // Catch InvalidDnDOperationException to fix #11259
414 Main.error(ex);
415 }
416 } finally {
417 // If it's a Swing component, reset its border
418 if (c instanceof JComponent) {
419 JComponent jc = (JComponent) c;
420 jc.setBorder(normalBorder);
421 Main.debug("FileDrop: normal border restored.");
422 }
423 }
424 }
425
426 @Override
427 public void dragExit(DropTargetEvent evt) {
428 Main.debug("FileDrop: dragExit event.");
429 // If it's a Swing component, reset its border
430 if (c instanceof JComponent) {
431 JComponent jc = (JComponent) c;
432 jc.setBorder(normalBorder);
433 Main.debug("FileDrop: normal border restored.");
434 }
435 }
436
437 @Override
438 public void dropActionChanged(DropTargetDragEvent evt) {
439 Main.debug("FileDrop: dropActionChanged event.");
440 // Is this an acceptable drag event?
441 if (isDragOk(evt)) {
442 evt.acceptDrag(DnDConstants.ACTION_COPY);
443 Main.debug("FileDrop: event accepted.");
444 } else {
445 evt.rejectDrag();
446 Main.debug("FileDrop: event rejected.");
447 }
448 }
449 }
450
451 /**
452 * Implement this inner interface to listen for when files are dropped. For example
453 * your class declaration may begin like this:
454 * <code>
455 * public class MyClass implements FileDrop.Listener
456 * ...
457 * public void filesDropped( java.io.File[] files )
458 * {
459 * ...
460 * } // end filesDropped
461 * ...
462 * </code>
463 */
464 public interface Listener {
465
466 /**
467 * This method is called when files have been successfully dropped.
468 *
469 * @param files An array of <tt>File</tt>s that were dropped.
470 */
471 void filesDropped(File[] files);
472 }
473
474 /* ******** I N N E R C L A S S ******** */
475
476 /**
477 * At last an easy way to encapsulate your custom objects for dragging and dropping
478 * in your Java programs!
479 * When you need to create a {@link java.awt.datatransfer.Transferable} object,
480 * use this class to wrap your object.
481 * For example:
482 * <pre><code>
483 * ...
484 * MyCoolClass myObj = new MyCoolClass();
485 * Transferable xfer = new TransferableObject( myObj );
486 * ...
487 * </code></pre>
488 * Or if you need to know when the data was actually dropped, like when you're
489 * moving data out of a list, say, you can use the {@link TransferableObject.Fetcher}
490 * inner class to return your object Just in Time.
491 * For example:
492 * <pre><code>
493 * ...
494 * final MyCoolClass myObj = new MyCoolClass();
495 *
496 * TransferableObject.Fetcher fetcher = new TransferableObject.Fetcher()
497 * { public Object getObject() { return myObj; }
498 * }; // end fetcher
499 *
500 * Transferable xfer = new TransferableObject( fetcher );
501 * ...
502 * </code></pre>
503 *
504 * The {@link java.awt.datatransfer.DataFlavor} associated with
505 * {@link TransferableObject} has the representation class
506 * <tt>net.iharder.dnd.TransferableObject.class</tt> and MIME type
507 * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
508 * This data flavor is accessible via the static
509 * {@link #DATA_FLAVOR} property.
510 *
511 *
512 * <p>I'm releasing this code into the Public Domain. Enjoy.</p>
513 *
514 * @author Robert Harder
515 * @author rob@iharder.net
516 * @version 1.2
517 */
518 public static class TransferableObject implements Transferable {
519
520 /**
521 * The MIME type for {@link #DATA_FLAVOR} is
522 * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
523 */
524 public static final String MIME_TYPE = "application/x-net.iharder.dnd.TransferableObject";
525
526 /**
527 * The default {@link java.awt.datatransfer.DataFlavor} for
528 * {@link TransferableObject} has the representation class
529 * <tt>net.iharder.dnd.TransferableObject.class</tt>
530 * and the MIME type
531 * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
532 */
533 public static final DataFlavor DATA_FLAVOR =
534 new DataFlavor(TransferableObject.class, MIME_TYPE);
535
536 private Fetcher fetcher;
537 private Object data;
538
539 private DataFlavor customFlavor;
540
541 /**
542 * Creates a new {@link TransferableObject} that wraps <var>data</var>.
543 * Along with the {@link #DATA_FLAVOR} associated with this class,
544 * this creates a custom data flavor with a representation class
545 * determined from <code>data.getClass()</code> and the MIME type
546 * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
547 *
548 * @param data The data to transfer
549 */
550 public TransferableObject(Object data) {
551 this.data = data;
552 this.customFlavor = new DataFlavor(data.getClass(), MIME_TYPE);
553 }
554
555 /**
556 * Creates a new {@link TransferableObject} that will return the
557 * object that is returned by <var>fetcher</var>.
558 * No custom data flavor is set other than the default
559 * {@link #DATA_FLAVOR}.
560 *
561 * @param fetcher The {@link Fetcher} that will return the data object
562 * @see Fetcher
563 */
564 public TransferableObject(Fetcher fetcher) {
565 this.fetcher = fetcher;
566 }
567
568 /**
569 * Creates a new {@link TransferableObject} that will return the
570 * object that is returned by <var>fetcher</var>.
571 * Along with the {@link #DATA_FLAVOR} associated with this class,
572 * this creates a custom data flavor with a representation class <var>dataClass</var>
573 * and the MIME type
574 * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
575 *
576 * @param dataClass The {@link java.lang.Class} to use in the custom data flavor
577 * @param fetcher The {@link Fetcher} that will return the data object
578 * @see Fetcher
579 */
580 public TransferableObject(Class<?> dataClass, Fetcher fetcher) {
581 this.fetcher = fetcher;
582 this.customFlavor = new DataFlavor(dataClass, MIME_TYPE);
583 }
584
585 /**
586 * Returns the custom {@link java.awt.datatransfer.DataFlavor} associated
587 * with the encapsulated object or <tt>null</tt> if the {@link Fetcher}
588 * constructor was used without passing a {@link java.lang.Class}.
589 *
590 * @return The custom data flavor for the encapsulated object
591 */
592 public DataFlavor getCustomDataFlavor() {
593 return customFlavor;
594 }
595
596 /* ******** T R A N S F E R A B L E M E T H O D S ******** */
597
598 /**
599 * Returns a two- or three-element array containing first
600 * the custom data flavor, if one was created in the constructors,
601 * second the default {@link #DATA_FLAVOR} associated with
602 * {@link TransferableObject}, and third the
603 * {@link java.awt.datatransfer.DataFlavor#stringFlavor}.
604 *
605 * @return An array of supported data flavors
606 */
607 @Override
608 public DataFlavor[] getTransferDataFlavors() {
609 if (customFlavor != null)
610 return new DataFlavor[] {
611 customFlavor,
612 DATA_FLAVOR,
613 DataFlavor.stringFlavor};
614 else
615 return new DataFlavor[] {
616 DATA_FLAVOR,
617 DataFlavor.stringFlavor};
618 }
619
620 /**
621 * Returns the data encapsulated in this {@link TransferableObject}.
622 * If the {@link Fetcher} constructor was used, then this is when
623 * the {@link Fetcher#getObject getObject()} method will be called.
624 * If the requested data flavor is not supported, then the
625 * {@link Fetcher#getObject getObject()} method will not be called.
626 *
627 * @param flavor The data flavor for the data to return
628 * @return The dropped data
629 */
630 @Override
631 public Object getTransferData(DataFlavor flavor)
632 throws UnsupportedFlavorException, IOException {
633 // Native object
634 if (flavor.equals(DATA_FLAVOR))
635 return fetcher == null ? data : fetcher.getObject();
636
637 // String
638 if (flavor.equals(DataFlavor.stringFlavor))
639 return fetcher == null ? data.toString() : fetcher.getObject().toString();
640
641 // We can't do anything else
642 throw new UnsupportedFlavorException(flavor);
643 }
644
645 /**
646 * Returns <tt>true</tt> if <var>flavor</var> is one of the supported
647 * flavors. Flavors are supported using the <code>equals(...)</code> method.
648 *
649 * @param flavor The data flavor to check
650 * @return Whether or not the flavor is supported
651 */
652 @Override
653 public boolean isDataFlavorSupported(DataFlavor flavor) {
654 // Native object
655 if (flavor.equals(DATA_FLAVOR))
656 return true;
657
658 // String
659 if (flavor.equals(DataFlavor.stringFlavor))
660 return true;
661
662 // We can't do anything else
663 return false;
664 }
665
666 /* ******** I N N E R I N T E R F A C E F E T C H E R ******** */
667
668 /**
669 * Instead of passing your data directly to the {@link TransferableObject}
670 * constructor, you may want to know exactly when your data was received
671 * in case you need to remove it from its source (or do anyting else to it).
672 * When the {@link #getTransferData getTransferData(...)} method is called
673 * on the {@link TransferableObject}, the {@link Fetcher}'s
674 * {@link #getObject getObject()} method will be called.
675 *
676 * @author Robert Harder
677 */
678 public interface Fetcher {
679 /**
680 * Return the object being encapsulated in the
681 * {@link TransferableObject}.
682 *
683 * @return The dropped object
684 */
685 Object getObject();
686 }
687 }
688}
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