001    /* code from: http://iharder.sourceforge.net/current/java/filedrop/
002      (public domain) with only very small additions */
003    package org.openstreetmap.josm.gui;
004    
005    import java.awt.datatransfer.DataFlavor;
006    import java.io.BufferedReader;
007    import java.io.File;
008    import java.io.IOException;
009    import java.io.PrintStream;
010    import java.io.Reader;
011    import java.util.Arrays;
012    import java.util.List;
013    
014    import javax.swing.BorderFactory;
015    
016    import org.openstreetmap.josm.Main;
017    import org.openstreetmap.josm.actions.OpenFileAction;
018    
019    /**
020     * This class makes it easy to drag and drop files from the operating
021     * system to a Java program. Any <tt>java.awt.Component</tt> can be
022     * dropped onto, but only <tt>javax.swing.JComponent</tt>s will indicate
023     * the drop event with a changed border.
024     * <p/>
025     * To use this class, construct a new <tt>FileDrop</tt> by passing
026     * it the target component and a <tt>Listener</tt> to receive notification
027     * when file(s) have been dropped. Here is an example:
028     * <p/>
029     * <code><pre>
030     *      JPanel myPanel = new JPanel();
031     *      new FileDrop( myPanel, new FileDrop.Listener()
032     *      {   public void filesDropped( java.io.File[] files )
033     *          {
034     *              // handle file drop
035     *              ...
036     *          }   // end filesDropped
037     *      }); // end FileDrop.Listener
038     * </pre></code>
039     * <p/>
040     * You can specify the border that will appear when files are being dragged by
041     * calling the constructor with a <tt>javax.swing.border.Border</tt>. Only
042     * <tt>JComponent</tt>s will show any indication with a border.
043     * <p/>
044     * You can turn on some debugging features by passing a <tt>PrintStream</tt>
045     * object (such as <tt>System.out</tt>) into the full constructor. A <tt>null</tt>
046     * value will result in no extra debugging information being output.
047     * <p/>
048     *
049     * <p>I'm releasing this code into the Public Domain. Enjoy.
050     * </p>
051     * <p><em>Original author: Robert Harder, rharder@usa.net</em></p>
052     * <p>2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.</p>
053     *
054     * @author  Robert Harder
055     * @author  rharder@users.sf.net
056     * @version 1.0.1
057     */
058    public class FileDrop
059    {
060        private transient javax.swing.border.Border normalBorder;
061        private transient java.awt.dnd.DropTargetListener dropListener;
062    
063        /** Discover if the running JVM is modern enough to have drag and drop. */
064        private static Boolean supportsDnD;
065    
066        // Default border color
067        private static java.awt.Color defaultBorderColor = new java.awt.Color( 0f, 0f, 1f, 0.25f );
068    
069        /* Constructor for JOSM file drop */
070        public FileDrop(final java.awt.Component c){
071            this(
072                    null,  // Logging stream
073                    c,     // Drop target
074                    BorderFactory.createMatteBorder( 2, 2, 2, 2, defaultBorderColor ), // Drag border
075                    true, // Recursive
076                    new FileDrop.Listener(){
077                        public void filesDropped( java.io.File[] files ){
078                            // start asynchronous loading of files
079                            OpenFileAction.OpenFileTask task = new OpenFileAction.OpenFileTask(Arrays.asList(files), null);
080                            task.setRecordHistory(true);
081                            Main.worker.submit(task);
082                        }
083                    }
084            );
085        }
086    
087        /**
088         * Constructs a {@link FileDrop} with a default light-blue border
089         * and, if <var>c</var> is a {@link java.awt.Container}, recursively
090         * sets all elements contained within as drop targets, though only
091         * the top level container will change borders.
092         *
093         * @param c Component on which files will be dropped.
094         * @param listener Listens for <tt>filesDropped</tt>.
095         * @since 1.0
096         */
097        public FileDrop(
098                final java.awt.Component c,
099                final Listener listener )
100        {   this( null,  // Logging stream
101                c,     // Drop target
102                javax.swing.BorderFactory.createMatteBorder( 2, 2, 2, 2, defaultBorderColor ), // Drag border
103                true, // Recursive
104                listener );
105        }   // end constructor
106    
107        /**
108         * Constructor with a default border and the option to recursively set drop targets.
109         * If your component is a <tt>java.awt.Container</tt>, then each of its children
110         * components will also listen for drops, though only the parent will change borders.
111         *
112         * @param c Component on which files will be dropped.
113         * @param recursive Recursively set children as drop targets.
114         * @param listener Listens for <tt>filesDropped</tt>.
115         * @since 1.0
116         */
117        public FileDrop(
118                final java.awt.Component c,
119                final boolean recursive,
120                final Listener listener )
121        {   this( null,  // Logging stream
122                c,     // Drop target
123                javax.swing.BorderFactory.createMatteBorder( 2, 2, 2, 2, defaultBorderColor ), // Drag border
124                recursive, // Recursive
125                listener );
126        }   // end constructor
127    
128        /**
129         * Constructor with a default border and debugging optionally turned on.
130         * With Debugging turned on, more status messages will be displayed to
131         * <tt>out</tt>. A common way to use this constructor is with
132         * <tt>System.out</tt> or <tt>System.err</tt>. A <tt>null</tt> value for
133         * the parameter <tt>out</tt> will result in no debugging output.
134         *
135         * @param out PrintStream to record debugging info or null for no debugging.
136         * @param c Component on which files will be dropped.
137         * @param listener Listens for <tt>filesDropped</tt>.
138         * @since 1.0
139         */
140        public FileDrop(
141                final java.io.PrintStream out,
142                final java.awt.Component c,
143                final Listener listener )
144        {   this( out,  // Logging stream
145                c,    // Drop target
146                javax.swing.BorderFactory.createMatteBorder( 2, 2, 2, 2, defaultBorderColor ),
147                false, // Recursive
148                listener );
149        }   // end constructor
150    
151        /**
152         * Constructor with a default border, debugging optionally turned on
153         * and the option to recursively set drop targets.
154         * If your component is a <tt>java.awt.Container</tt>, then each of its children
155         * components will also listen for drops, though only the parent will change borders.
156         * With Debugging turned on, more status messages will be displayed to
157         * <tt>out</tt>. A common way to use this constructor is with
158         * <tt>System.out</tt> or <tt>System.err</tt>. A <tt>null</tt> value for
159         * the parameter <tt>out</tt> will result in no debugging output.
160         *
161         * @param out PrintStream to record debugging info or null for no debugging.
162         * @param c Component on which files will be dropped.
163         * @param recursive Recursively set children as drop targets.
164         * @param listener Listens for <tt>filesDropped</tt>.
165         * @since 1.0
166         */
167        public FileDrop(
168                final java.io.PrintStream out,
169                final java.awt.Component c,
170                final boolean recursive,
171                final Listener listener)
172        {   this( out,  // Logging stream
173                c,    // Drop target
174                javax.swing.BorderFactory.createMatteBorder( 2, 2, 2, 2, defaultBorderColor ), // Drag border
175                recursive, // Recursive
176                listener );
177        }   // end constructor
178    
179        /**
180         * Constructor with a specified border
181         *
182         * @param c Component on which files will be dropped.
183         * @param dragBorder Border to use on <tt>JComponent</tt> when dragging occurs.
184         * @param listener Listens for <tt>filesDropped</tt>.
185         * @since 1.0
186         */
187        public FileDrop(
188                final java.awt.Component c,
189                final javax.swing.border.Border dragBorder,
190                final Listener listener)
191        {   this(
192                null,   // Logging stream
193                c,      // Drop target
194                dragBorder, // Drag border
195                false,  // Recursive
196                listener );
197        }   // end constructor
198    
199        /**
200         * Constructor with a specified border and the option to recursively set drop targets.
201         * If your component is a <tt>java.awt.Container</tt>, then each of its children
202         * components will also listen for drops, though only the parent will change borders.
203         *
204         * @param c Component on which files will be dropped.
205         * @param dragBorder Border to use on <tt>JComponent</tt> when dragging occurs.
206         * @param recursive Recursively set children as drop targets.
207         * @param listener Listens for <tt>filesDropped</tt>.
208         * @since 1.0
209         */
210        public FileDrop(
211                final java.awt.Component c,
212                final javax.swing.border.Border dragBorder,
213                final boolean recursive,
214                final Listener listener)
215        {   this(
216                null,
217                c,
218                dragBorder,
219                recursive,
220                listener );
221        }   // end constructor
222    
223        /**
224         * Constructor with a specified border and debugging optionally turned on.
225         * With Debugging turned on, more status messages will be displayed to
226         * <tt>out</tt>. A common way to use this constructor is with
227         * <tt>System.out</tt> or <tt>System.err</tt>. A <tt>null</tt> value for
228         * the parameter <tt>out</tt> will result in no debugging output.
229         *
230         * @param out PrintStream to record debugging info or null for no debugging.
231         * @param c Component on which files will be dropped.
232         * @param dragBorder Border to use on <tt>JComponent</tt> when dragging occurs.
233         * @param listener Listens for <tt>filesDropped</tt>.
234         * @since 1.0
235         */
236        public FileDrop(
237                final java.io.PrintStream out,
238                final java.awt.Component c,
239                final javax.swing.border.Border dragBorder,
240                final Listener listener)
241        {   this(
242                out,    // Logging stream
243                c,      // Drop target
244                dragBorder, // Drag border
245                false,  // Recursive
246                listener );
247        }   // end constructor
248    
249        /**
250         * Full constructor with a specified border and debugging optionally turned on.
251         * With Debugging turned on, more status messages will be displayed to
252         * <tt>out</tt>. A common way to use this constructor is with
253         * <tt>System.out</tt> or <tt>System.err</tt>. A <tt>null</tt> value for
254         * the parameter <tt>out</tt> will result in no debugging output.
255         *
256         * @param out PrintStream to record debugging info or null for no debugging.
257         * @param c Component on which files will be dropped.
258         * @param dragBorder Border to use on <tt>JComponent</tt> when dragging occurs.
259         * @param recursive Recursively set children as drop targets.
260         * @param listener Listens for <tt>filesDropped</tt>.
261         * @since 1.0
262         */
263        public FileDrop(
264                final java.io.PrintStream out,
265                final java.awt.Component c,
266                final javax.swing.border.Border dragBorder,
267                final boolean recursive,
268                final Listener listener)
269        {
270    
271            if( supportsDnD() )
272            {   // Make a drop listener
273                dropListener = new java.awt.dnd.DropTargetListener()
274                {   public void dragEnter( java.awt.dnd.DropTargetDragEvent evt )
275                {       log( out, "FileDrop: dragEnter event." );
276    
277                // Is this an acceptable drag event?
278                if( isDragOk( out, evt ) )
279                {
280                    // If it's a Swing component, set its border
281                    if( c instanceof javax.swing.JComponent )
282                    {   javax.swing.JComponent jc = (javax.swing.JComponent) c;
283                    normalBorder = jc.getBorder();
284                    log( out, "FileDrop: normal border saved." );
285                    jc.setBorder( dragBorder );
286                    log( out, "FileDrop: drag border set." );
287                    }   // end if: JComponent
288    
289                    // Acknowledge that it's okay to enter
290                    //evt.acceptDrag( java.awt.dnd.DnDConstants.ACTION_COPY_OR_MOVE );
291                    evt.acceptDrag( java.awt.dnd.DnDConstants.ACTION_COPY );
292                    log( out, "FileDrop: event accepted." );
293                }   // end if: drag ok
294                else
295                {   // Reject the drag event
296                    evt.rejectDrag();
297                    log( out, "FileDrop: event rejected." );
298                }   // end else: drag not ok
299                }   // end dragEnter
300    
301                public void dragOver( java.awt.dnd.DropTargetDragEvent evt )
302                {   // This is called continually as long as the mouse is
303                    // over the drag target.
304                }   // end dragOver
305    
306                public void drop( java.awt.dnd.DropTargetDropEvent evt )
307                {   log( out, "FileDrop: drop event." );
308                try
309                {   // Get whatever was dropped
310                    java.awt.datatransfer.Transferable tr = evt.getTransferable();
311    
312                    // Is it a file list?
313                    if (tr.isDataFlavorSupported (java.awt.datatransfer.DataFlavor.javaFileListFlavor))
314                    {
315                        // Say we'll take it.
316                        //evt.acceptDrop ( java.awt.dnd.DnDConstants.ACTION_COPY_OR_MOVE );
317                        evt.acceptDrop ( java.awt.dnd.DnDConstants.ACTION_COPY );
318                        log( out, "FileDrop: file list accepted." );
319    
320                        // Get a useful list
321                        List<?> fileList = (List<?>)tr.getTransferData(java.awt.datatransfer.DataFlavor.javaFileListFlavor);
322    
323                        // Convert list to array
324                        final File[] files = fileList.toArray(new File[fileList.size()]);
325    
326                        // Alert listener to drop.
327                        if( listener != null ) {
328                            listener.filesDropped( files );
329                        }
330    
331                        // Mark that drop is completed.
332                        evt.getDropTargetContext().dropComplete(true);
333                        log( out, "FileDrop: drop complete." );
334                    }   // end if: file list
335                    else // this section will check for a reader flavor.
336                    {
337                        // Thanks, Nathan!
338                        // BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
339                        DataFlavor[] flavors = tr.getTransferDataFlavors();
340                        boolean handled = false;
341                        for (int zz = 0; zz < flavors.length; zz++) {
342                            if (flavors[zz].isRepresentationClassReader()) {
343                                // Say we'll take it.
344                                //evt.acceptDrop ( java.awt.dnd.DnDConstants.ACTION_COPY_OR_MOVE );
345                                evt.acceptDrop(java.awt.dnd.DnDConstants.ACTION_COPY);
346                                log(out, "FileDrop: reader accepted.");
347    
348                                Reader reader = flavors[zz].getReaderForText(tr);
349    
350                                BufferedReader br = new BufferedReader(reader);
351    
352                                if(listener != null) {
353                                    listener.filesDropped(createFileArray(br, out));
354                                }
355    
356                                // Mark that drop is completed.
357                                evt.getDropTargetContext().dropComplete(true);
358                                log(out, "FileDrop: drop complete.");
359                                handled = true;
360                                break;
361                            }
362                        }
363                        if(!handled){
364                            log( out, "FileDrop: not a file list or reader - abort." );
365                            evt.rejectDrop();
366                        }
367                        // END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
368                    }   // end else: not a file list
369                }   // end try
370                catch ( java.io.IOException io)
371                {   log( out, "FileDrop: IOException - abort:" );
372                io.printStackTrace( out );
373                evt.rejectDrop();
374                }   // end catch IOException
375                catch (java.awt.datatransfer.UnsupportedFlavorException ufe)
376                {   log( out, "FileDrop: UnsupportedFlavorException - abort:" );
377                ufe.printStackTrace( out );
378                evt.rejectDrop();
379                }   // end catch: UnsupportedFlavorException
380                finally
381                {
382                    // If it's a Swing component, reset its border
383                    if( c instanceof javax.swing.JComponent )
384                    {   javax.swing.JComponent jc = (javax.swing.JComponent) c;
385                    jc.setBorder( normalBorder );
386                    log( out, "FileDrop: normal border restored." );
387                    }   // end if: JComponent
388                }   // end finally
389                }   // end drop
390    
391                public void dragExit( java.awt.dnd.DropTargetEvent evt )
392                {   log( out, "FileDrop: dragExit event." );
393                // If it's a Swing component, reset its border
394                if( c instanceof javax.swing.JComponent )
395                {   javax.swing.JComponent jc = (javax.swing.JComponent) c;
396                jc.setBorder( normalBorder );
397                log( out, "FileDrop: normal border restored." );
398                }   // end if: JComponent
399                }   // end dragExit
400    
401                public void dropActionChanged( java.awt.dnd.DropTargetDragEvent evt )
402                {   log( out, "FileDrop: dropActionChanged event." );
403                // Is this an acceptable drag event?
404                if( isDragOk( out, evt ) )
405                {   //evt.acceptDrag( java.awt.dnd.DnDConstants.ACTION_COPY_OR_MOVE );
406                    evt.acceptDrag( java.awt.dnd.DnDConstants.ACTION_COPY );
407                    log( out, "FileDrop: event accepted." );
408                }   // end if: drag ok
409                else
410                {   evt.rejectDrag();
411                log( out, "FileDrop: event rejected." );
412                }   // end else: drag not ok
413                }   // end dropActionChanged
414                }; // end DropTargetListener
415    
416                // Make the component (and possibly children) drop targets
417                makeDropTarget( out, c, recursive );
418            }   // end if: supports dnd
419            else
420            {   log( out, "FileDrop: Drag and drop is not supported with this JVM" );
421            }   // end else: does not support DnD
422        }   // end constructor
423    
424        private static boolean supportsDnD()
425        {   // Static Boolean
426            if( supportsDnD == null )
427            {
428                boolean support = false;
429                try {
430                    Class.forName( "java.awt.dnd.DnDConstants" );
431                    support = true;
432                } catch( Exception e ) {
433                    support = false;
434                }
435                supportsDnD = support;
436            }   // end if: first time through
437            return supportsDnD.booleanValue();
438        }   // end supportsDnD
439    
440        // BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
441        private static String ZERO_CHAR_STRING = "" + (char)0;
442        private static File[] createFileArray(BufferedReader bReader, PrintStream out)
443        {
444            try {
445                java.util.List<File> list = new java.util.ArrayList<File>();
446                java.lang.String line = null;
447                while ((line = bReader.readLine()) != null) {
448                    try {
449                        // kde seems to append a 0 char to the end of the reader
450                        if(ZERO_CHAR_STRING.equals(line)) {
451                            continue;
452                        }
453    
454                        java.io.File file = new java.io.File(new java.net.URI(line));
455                        list.add(file);
456                    } catch (Exception ex) {
457                        log(out, "Error with " + line + ": " + ex.getMessage());
458                    }
459                }
460    
461                return list.toArray(new File[list.size()]);
462            } catch (IOException ex) {
463                log(out, "FileDrop: IOException");
464            }
465            return new File[0];
466        }
467        // END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
468    
469        private void makeDropTarget( final java.io.PrintStream out, final java.awt.Component c, boolean recursive )
470        {
471            // Make drop target
472            final java.awt.dnd.DropTarget dt = new java.awt.dnd.DropTarget();
473            try
474            {   dt.addDropTargetListener( dropListener );
475            }   // end try
476            catch( java.util.TooManyListenersException e )
477            {   e.printStackTrace();
478            log(out, "FileDrop: Drop will not work due to previous error. Do you have another listener attached?" );
479            }   // end catch
480    
481            // Listen for hierarchy changes and remove the drop target when the parent gets cleared out.
482            c.addHierarchyListener( new java.awt.event.HierarchyListener()
483            {   public void hierarchyChanged( java.awt.event.HierarchyEvent evt )
484            {   log( out, "FileDrop: Hierarchy changed." );
485            java.awt.Component parent = c.getParent();
486            if( parent == null )
487            {   c.setDropTarget( null );
488            log( out, "FileDrop: Drop target cleared from component." );
489            }   // end if: null parent
490            else
491            {   new java.awt.dnd.DropTarget(c, dropListener);
492            log( out, "FileDrop: Drop target added to component." );
493            }   // end else: parent not null
494            }   // end hierarchyChanged
495            }); // end hierarchy listener
496            if( c.getParent() != null ) {
497                new java.awt.dnd.DropTarget(c, dropListener);
498            }
499    
500            if( recursive && (c instanceof java.awt.Container ) )
501            {
502                // Get the container
503                java.awt.Container cont = (java.awt.Container) c;
504    
505                // Get it's components
506                java.awt.Component[] comps = cont.getComponents();
507    
508                // Set it's components as listeners also
509                for( int i = 0; i < comps.length; i++ ) {
510                    makeDropTarget( out, comps[i], recursive );
511                }
512            }   // end if: recursively set components as listener
513        }   // end dropListener
514    
515        /** Determine if the dragged data is a file list. */
516        private boolean isDragOk( final java.io.PrintStream out, final java.awt.dnd.DropTargetDragEvent evt )
517        {   boolean ok = false;
518    
519        // Get data flavors being dragged
520        java.awt.datatransfer.DataFlavor[] flavors = evt.getCurrentDataFlavors();
521    
522        // See if any of the flavors are a file list
523        int i = 0;
524        while( !ok && i < flavors.length )
525        {
526            // BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
527            // Is the flavor a file list?
528            final DataFlavor curFlavor = flavors[i];
529            if( curFlavor.equals( java.awt.datatransfer.DataFlavor.javaFileListFlavor ) ||
530                    curFlavor.isRepresentationClassReader()){
531                ok = true;
532            }
533            // END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
534            i++;
535        }   // end while: through flavors
536    
537        // If logging is enabled, show data flavors
538        if( out != null )
539        {   if( flavors.length == 0 ) {
540            log( out, "FileDrop: no data flavors." );
541        }
542        for( i = 0; i < flavors.length; i++ ) {
543            log( out, flavors[i].toString() );
544        }
545        }   // end if: logging enabled
546    
547        return ok;
548        }   // end isDragOk
549    
550        /** Outputs <tt>message</tt> to <tt>out</tt> if it's not null. */
551        private static void log( java.io.PrintStream out, String message )
552        {   // Log message if requested
553            if( out != null ) {
554                out.println( message );
555            }
556        }   // end log
557    
558        /**
559         * Removes the drag-and-drop hooks from the component and optionally
560         * from the all children. You should call this if you add and remove
561         * components after you've set up the drag-and-drop.
562         * This will recursively unregister all components contained within
563         * <var>c</var> if <var>c</var> is a {@link java.awt.Container}.
564         *
565         * @param c The component to unregister as a drop target
566         * @since 1.0
567         */
568        public static boolean remove( java.awt.Component c)
569        {   return remove( null, c, true );
570        }   // end remove
571    
572        /**
573         * Removes the drag-and-drop hooks from the component and optionally
574         * from the all children. You should call this if you add and remove
575         * components after you've set up the drag-and-drop.
576         *
577         * @param out Optional {@link java.io.PrintStream} for logging drag and drop messages
578         * @param c The component to unregister
579         * @param recursive Recursively unregister components within a container
580         * @since 1.0
581         */
582        public static boolean remove( java.io.PrintStream out, java.awt.Component c, boolean recursive )
583        {   // Make sure we support dnd.
584            if( supportsDnD() )
585            {   log( out, "FileDrop: Removing drag-and-drop hooks." );
586            c.setDropTarget( null );
587            if( recursive && ( c instanceof java.awt.Container ) )
588            {   java.awt.Component[] comps = ((java.awt.Container)c).getComponents();
589            for( int i = 0; i < comps.length; i++ ) {
590                remove( out, comps[i], recursive );
591            }
592            return true;
593            }   // end if: recursive
594            else return false;
595            }   // end if: supports DnD
596            else return false;
597        }   // end remove
598    
599        /* ********  I N N E R   I N T E R F A C E   L I S T E N E R  ******** */
600    
601        /**
602         * Implement this inner interface to listen for when files are dropped. For example
603         * your class declaration may begin like this:
604         * <code><pre>
605         *      public class MyClass implements FileDrop.Listener
606         *      ...
607         *      public void filesDropped( java.io.File[] files )
608         *      {
609         *          ...
610         *      }   // end filesDropped
611         *      ...
612         * </pre></code>
613         *
614         * @since 1.1
615         */
616        public static interface Listener {
617    
618            /**
619             * This method is called when files have been successfully dropped.
620             *
621             * @param files An array of <tt>File</tt>s that were dropped.
622             * @since 1.0
623             */
624            public abstract void filesDropped( java.io.File[] files );
625    
626        }   // end inner-interface Listener
627    
628        /* ********  I N N E R   C L A S S  ******** */
629    
630        /**
631         * This is the event that is passed to the
632         * {@link FileDropListener#filesDropped filesDropped(...)} method in
633         * your {@link FileDropListener} when files are dropped onto
634         * a registered drop target.
635         *
636         * <p>I'm releasing this code into the Public Domain. Enjoy.</p>
637         *
638         * @author  Robert Harder
639         * @author  rob@iharder.net
640         * @version 1.2
641         */
642        public static class Event extends java.util.EventObject {
643    
644            private java.io.File[] files;
645    
646            /**
647             * Constructs an {@link Event} with the array
648             * of files that were dropped and the
649             * {@link FileDrop} that initiated the event.
650             *
651             * @param files The array of files that were dropped
652             * @source The event source
653             * @since 1.1
654             */
655            public Event( java.io.File[] files, Object source ) {
656                super( source );
657                this.files = files;
658            }   // end constructor
659    
660            /**
661             * Returns an array of files that were dropped on a
662             * registered drop target.
663             *
664             * @return array of files that were dropped
665             * @since 1.1
666             */
667            public java.io.File[] getFiles() {
668                return files;
669            }   // end getFiles
670    
671        }   // end inner class Event
672    
673        /* ********  I N N E R   C L A S S  ******** */
674    
675        /**
676         * At last an easy way to encapsulate your custom objects for dragging and dropping
677         * in your Java programs!
678         * When you need to create a {@link java.awt.datatransfer.Transferable} object,
679         * use this class to wrap your object.
680         * For example:
681         * <pre><code>
682         *      ...
683         *      MyCoolClass myObj = new MyCoolClass();
684         *      Transferable xfer = new TransferableObject( myObj );
685         *      ...
686         * </code></pre>
687         * Or if you need to know when the data was actually dropped, like when you're
688         * moving data out of a list, say, you can use the {@link TransferableObject.Fetcher}
689         * inner class to return your object Just in Time.
690         * For example:
691         * <pre><code>
692         *      ...
693         *      final MyCoolClass myObj = new MyCoolClass();
694         *
695         *      TransferableObject.Fetcher fetcher = new TransferableObject.Fetcher()
696         *      {   public Object getObject(){ return myObj; }
697         *      }; // end fetcher
698         *
699         *      Transferable xfer = new TransferableObject( fetcher );
700         *      ...
701         * </code></pre>
702         *
703         * The {@link java.awt.datatransfer.DataFlavor} associated with
704         * {@link TransferableObject} has the representation class
705         * <tt>net.iharder.dnd.TransferableObject.class</tt> and MIME type
706         * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
707         * This data flavor is accessible via the static
708         * {@link #DATA_FLAVOR} property.
709         *
710         *
711         * <p>I'm releasing this code into the Public Domain. Enjoy.</p>
712         *
713         * @author  Robert Harder
714         * @author  rob@iharder.net
715         * @version 1.2
716         */
717        public static class TransferableObject implements java.awt.datatransfer.Transferable
718        {
719            /**
720             * The MIME type for {@link #DATA_FLAVOR} is
721             * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
722             *
723             * @since 1.1
724             */
725            public final static String MIME_TYPE = "application/x-net.iharder.dnd.TransferableObject";
726    
727            /**
728             * The default {@link java.awt.datatransfer.DataFlavor} for
729             * {@link TransferableObject} has the representation class
730             * <tt>net.iharder.dnd.TransferableObject.class</tt>
731             * and the MIME type
732             * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
733             *
734             * @since 1.1
735             */
736            public final static java.awt.datatransfer.DataFlavor DATA_FLAVOR =
737                new java.awt.datatransfer.DataFlavor( FileDrop.TransferableObject.class, MIME_TYPE );
738    
739            private Fetcher fetcher;
740            private Object data;
741    
742            private java.awt.datatransfer.DataFlavor customFlavor;
743    
744            /**
745             * Creates a new {@link TransferableObject} that wraps <var>data</var>.
746             * Along with the {@link #DATA_FLAVOR} associated with this class,
747             * this creates a custom data flavor with a representation class
748             * determined from <code>data.getClass()</code> and the MIME type
749             * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
750             *
751             * @param data The data to transfer
752             * @since 1.1
753             */
754            public TransferableObject( Object data )
755            {   this.data = data;
756            this.customFlavor = new java.awt.datatransfer.DataFlavor( data.getClass(), MIME_TYPE );
757            }   // end constructor
758    
759            /**
760             * Creates a new {@link TransferableObject} that will return the
761             * object that is returned by <var>fetcher</var>.
762             * No custom data flavor is set other than the default
763             * {@link #DATA_FLAVOR}.
764             *
765             * @see Fetcher
766             * @param fetcher The {@link Fetcher} that will return the data object
767             * @since 1.1
768             */
769            public TransferableObject( Fetcher fetcher )
770            {   this.fetcher = fetcher;
771            }   // end constructor
772    
773            /**
774             * Creates a new {@link TransferableObject} that will return the
775             * object that is returned by <var>fetcher</var>.
776             * Along with the {@link #DATA_FLAVOR} associated with this class,
777             * this creates a custom data flavor with a representation class <var>dataClass</var>
778             * and the MIME type
779             * <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
780             *
781             * @see Fetcher
782             * @param dataClass The {@link java.lang.Class} to use in the custom data flavor
783             * @param fetcher The {@link Fetcher} that will return the data object
784             * @since 1.1
785             */
786            public TransferableObject(Class<?> dataClass, Fetcher fetcher )
787            {   this.fetcher = fetcher;
788            this.customFlavor = new java.awt.datatransfer.DataFlavor( dataClass, MIME_TYPE );
789            }   // end constructor
790    
791            /**
792             * Returns the custom {@link java.awt.datatransfer.DataFlavor} associated
793             * with the encapsulated object or <tt>null</tt> if the {@link Fetcher}
794             * constructor was used without passing a {@link java.lang.Class}.
795             *
796             * @return The custom data flavor for the encapsulated object
797             * @since 1.1
798             */
799            public java.awt.datatransfer.DataFlavor getCustomDataFlavor()
800            {   return customFlavor;
801            }   // end getCustomDataFlavor
802    
803            /* ********  T R A N S F E R A B L E   M E T H O D S  ******** */
804    
805            /**
806             * Returns a two- or three-element array containing first
807             * the custom data flavor, if one was created in the constructors,
808             * second the default {@link #DATA_FLAVOR} associated with
809             * {@link TransferableObject}, and third the
810             * {@link java.awt.datatransfer.DataFlavor.stringFlavor}.
811             *
812             * @return An array of supported data flavors
813             * @since 1.1
814             */
815            public java.awt.datatransfer.DataFlavor[] getTransferDataFlavors()
816            {
817                if( customFlavor != null )
818                    return new java.awt.datatransfer.DataFlavor[]
819                                                                {   customFlavor,
820                        DATA_FLAVOR,
821                        java.awt.datatransfer.DataFlavor.stringFlavor
822                                                                };  // end flavors array
823                else
824                    return new java.awt.datatransfer.DataFlavor[]
825                                                                {   DATA_FLAVOR,
826                        java.awt.datatransfer.DataFlavor.stringFlavor
827                                                                };  // end flavors array
828            }   // end getTransferDataFlavors
829    
830            /**
831             * Returns the data encapsulated in this {@link TransferableObject}.
832             * If the {@link Fetcher} constructor was used, then this is when
833             * the {@link Fetcher#getObject getObject()} method will be called.
834             * If the requested data flavor is not supported, then the
835             * {@link Fetcher#getObject getObject()} method will not be called.
836             *
837             * @param flavor The data flavor for the data to return
838             * @return The dropped data
839             * @since 1.1
840             */
841            public Object getTransferData( java.awt.datatransfer.DataFlavor flavor )
842            throws java.awt.datatransfer.UnsupportedFlavorException, java.io.IOException
843            {
844                // Native object
845                if( flavor.equals( DATA_FLAVOR ) )
846                    return fetcher == null ? data : fetcher.getObject();
847    
848                // String
849                if( flavor.equals( java.awt.datatransfer.DataFlavor.stringFlavor ) )
850                    return fetcher == null ? data.toString() : fetcher.getObject().toString();
851    
852                    // We can't do anything else
853                    throw new java.awt.datatransfer.UnsupportedFlavorException(flavor);
854            }   // end getTransferData
855    
856            /**
857             * Returns <tt>true</tt> if <var>flavor</var> is one of the supported
858             * flavors. Flavors are supported using the <code>equals(...)</code> method.
859             *
860             * @param flavor The data flavor to check
861             * @return Whether or not the flavor is supported
862             * @since 1.1
863             */
864            public boolean isDataFlavorSupported( java.awt.datatransfer.DataFlavor flavor )
865            {
866                // Native object
867                if( flavor.equals( DATA_FLAVOR ) )
868                    return true;
869    
870                // String
871                if( flavor.equals( java.awt.datatransfer.DataFlavor.stringFlavor ) )
872                    return true;
873    
874                // We can't do anything else
875                return false;
876            }   // end isDataFlavorSupported
877    
878            /* ********  I N N E R   I N T E R F A C E   F E T C H E R  ******** */
879    
880            /**
881             * Instead of passing your data directly to the {@link TransferableObject}
882             * constructor, you may want to know exactly when your data was received
883             * in case you need to remove it from its source (or do anyting else to it).
884             * When the {@link #getTransferData getTransferData(...)} method is called
885             * on the {@link TransferableObject}, the {@link Fetcher}'s
886             * {@link #getObject getObject()} method will be called.
887             *
888             * @author Robert Harder
889             * @copyright 2001
890             * @version 1.1
891             * @since 1.1
892             */
893            public static interface Fetcher
894            {
895                /**
896                 * Return the object being encapsulated in the
897                 * {@link TransferableObject}.
898                 *
899                 * @return The dropped object
900                 * @since 1.1
901                 */
902                public abstract Object getObject();
903            }   // end inner interface Fetcher
904    
905        }   // end class TransferableObject
906    
907    }   // end class FileDrop