/* code from: http://iharder.sourceforge.net/current/java/filedrop/
(public domain) with only very small additions */
package org.openstreetmap.josm.gui;
import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.awt.event.HierarchyEvent;
import java.awt.event.HierarchyListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.Reader;
import java.net.URI;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.TooManyListenersException;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.border.Border;
import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.actions.OpenFileAction;
/**
* This class makes it easy to drag and drop files from the operating
* system to a Java program. Any {@link java.awt.Component} can be
* dropped onto, but only {@link javax.swing.JComponent}s will indicate
* the drop event with a changed border.
* <p>
* To use this class, construct a new <tt>FileDrop</tt> by passing
* it the target component and a <tt>Listener</tt> to receive notification
* when file(s) have been dropped. Here is an example:
* <p>
* <code>
* JPanel myPanel = new JPanel();
* new FileDrop( myPanel, new FileDrop.Listener()
* { public void filesDropped( java.io.File[] files )
* {
* // handle file drop
* ...
* } // end filesDropped
* }); // end FileDrop.Listener
* </code>
* <p>
* You can specify the border that will appear when files are being dragged by
* calling the constructor with a {@link javax.swing.border.Border}. Only
* <tt>JComponent</tt>s will show any indication with a border.
* <p>
* You can turn on some debugging features by passing a <tt>PrintStream</tt>
* object (such as <tt>System.out</tt>) into the full constructor. A <tt>null</tt>
* value will result in no extra debugging information being output.
* <p>
*
* <p>I'm releasing this code into the Public Domain. Enjoy.
* </p>
* <p><em>Original author: Robert Harder, rharder@usa.net</em></p>
* <p>2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.</p>
*
* @author Robert Harder
* @author rharder@users.sf.net
* @version 1.0.1
* @since 1231
*/
public class FileDrop
{
private transient Border normalBorder;
private transient DropTargetListener dropListener;
/** Discover if the running JVM is modern enough to have drag and drop. */
private static Boolean supportsDnD;
// Default border color
private static Color defaultBorderColor = new Color( 0f, 0f, 1f, 0.25f );
/**
* Constructor for JOSM file drop
* @param c The drop target
*/
public FileDrop(final Component c){
this(
c, // Drop target
BorderFactory.createMatteBorder( 2, 2, 2, 2, defaultBorderColor ), // Drag border
true, // Recursive
new FileDrop.Listener(){
@Override
public void filesDropped( File[] files ){
// start asynchronous loading of files
OpenFileAction.OpenFileTask task = new OpenFileAction.OpenFileTask(Arrays.asList(files), null);
task.setRecordHistory(true);
Main.worker.submit(task);
}
}
);
}
/**
* Full constructor with a specified border and debugging optionally turned on.
* With Debugging turned on, more status messages will be displayed to
* <tt>out</tt>. A common way to use this constructor is with
* <tt>System.out</tt> or <tt>System.err</tt>. A <tt>null</tt> value for
* the parameter <tt>out</tt> will result in no debugging output.
*
* @param c Component on which files will be dropped.
* @param dragBorder Border to use on <tt>JComponent</tt> when dragging occurs.
* @param recursive Recursively set children as drop targets.
* @param listener Listens for <tt>filesDropped</tt>.
*/
public FileDrop(
final Component c,
final Border dragBorder,
final boolean recursive,
final Listener listener)
{
if( supportsDnD() )
{ // Make a drop listener
dropListener = new DropTargetListener()
{ @Override
public void dragEnter( DropTargetDragEvent evt )
{ Main.trace("FileDrop: dragEnter event." );
// Is this an acceptable drag event?
if( isDragOk( evt ) )
{
// If it's a Swing component, set its border
if( c instanceof JComponent )
{ JComponent jc = (JComponent) c;
normalBorder = jc.getBorder();
Main.trace("FileDrop: normal border saved." );
jc.setBorder( dragBorder );
Main.trace("FileDrop: drag border set." );
} // end if: JComponent
// Acknowledge that it's okay to enter
evt.acceptDrag( DnDConstants.ACTION_COPY );
Main.trace("FileDrop: event accepted." );
} // end if: drag ok
else
{ // Reject the drag event
evt.rejectDrag();
Main.trace("FileDrop: event rejected." );
} // end else: drag not ok
} // end dragEnter
@Override
public void dragOver( DropTargetDragEvent evt )
{ // This is called continually as long as the mouse is
// over the drag target.
} // end dragOver
@Override
public void drop( DropTargetDropEvent evt )
{ Main.trace("FileDrop: drop event." );
try
{ // Get whatever was dropped
Transferable tr = evt.getTransferable();
// Is it a file list?
if (tr.isDataFlavorSupported (DataFlavor.javaFileListFlavor))
{
// Say we'll take it.
evt.acceptDrop ( DnDConstants.ACTION_COPY );
Main.trace("FileDrop: file list accepted." );
// Get a useful list
List<?> fileList = (List<?>)tr.getTransferData(DataFlavor.javaFileListFlavor);
// Convert list to array
final File[] files = fileList.toArray(new File[fileList.size()]);
// Alert listener to drop.
if( listener != null ) {
listener.filesDropped( files );
}
// Mark that drop is completed.
evt.getDropTargetContext().dropComplete(true);
Main.trace("FileDrop: drop complete." );
} // end if: file list
else // this section will check for a reader flavor.
{
// Thanks, Nathan!
// BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
DataFlavor[] flavors = tr.getTransferDataFlavors();
boolean handled = false;
for (DataFlavor flavor : flavors) {
if (flavor.isRepresentationClassReader()) {
// Say we'll take it.
evt.acceptDrop(DnDConstants.ACTION_COPY);
Main.trace("FileDrop: reader accepted.");
Reader reader = flavor.getReaderForText(tr);
BufferedReader br = new BufferedReader(reader);
if (listener != null) {
listener.filesDropped(createFileArray(br));
}
// Mark that drop is completed.
evt.getDropTargetContext().dropComplete(true);
Main.trace("FileDrop: drop complete.");
handled = true;
break;
}
}
if(!handled){
Main.trace("FileDrop: not a file list or reader - abort." );
evt.rejectDrop();
}
// END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
} // end else: not a file list
} // end try
catch ( IOException io)
{ Main.warn("FileDrop: IOException - abort:" );
Main.error(io);
evt.rejectDrop();
} // end catch IOException
catch (UnsupportedFlavorException ufe)
{ Main.warn("FileDrop: UnsupportedFlavorException - abort:" );
Main.error(ufe);
evt.rejectDrop();
} // end catch: UnsupportedFlavorException
finally
{
// If it's a Swing component, reset its border
if( c instanceof JComponent )
{ JComponent jc = (JComponent) c;
jc.setBorder( normalBorder );
Main.debug("FileDrop: normal border restored." );
} // end if: JComponent
} // end finally
} // end drop
@Override
public void dragExit( DropTargetEvent evt )
{ Main.debug("FileDrop: dragExit event." );
// If it's a Swing component, reset its border
if( c instanceof JComponent )
{ JComponent jc = (JComponent) c;
jc.setBorder( normalBorder );
Main.debug("FileDrop: normal border restored." );
} // end if: JComponent
} // end dragExit
@Override
public void dropActionChanged( DropTargetDragEvent evt )
{ Main.debug("FileDrop: dropActionChanged event." );
// Is this an acceptable drag event?
if( isDragOk( evt ) )
{
evt.acceptDrag( DnDConstants.ACTION_COPY );
Main.debug("FileDrop: event accepted." );
} // end if: drag ok
else
{ evt.rejectDrag();
Main.debug("FileDrop: event rejected." );
} // end else: drag not ok
} // end dropActionChanged
}; // end DropTargetListener
// Make the component (and possibly children) drop targets
makeDropTarget( c, recursive );
} // end if: supports dnd
else
{ Main.info("FileDrop: Drag and drop is not supported with this JVM" );
} // end else: does not support DnD
} // end constructor
private static boolean supportsDnD()
{ // Static Boolean
if( supportsDnD == null )
{
boolean support = false;
try {
Class.forName( "java.awt.dnd.DnDConstants" );
support = true;
} catch( Exception e ) {
support = false;
}
supportsDnD = support;
} // end if: first time through
return supportsDnD.booleanValue();
} // end supportsDnD
// BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
private static final String ZERO_CHAR_STRING = "" + (char)0;
private static File[] createFileArray(BufferedReader bReader)
{
try {
List<File> list = new ArrayList<>();
String line = null;
while ((line = bReader.readLine()) != null) {
try {
// kde seems to append a 0 char to the end of the reader
if (ZERO_CHAR_STRING.equals(line)) {
continue;
}
File file = new File(new URI(line));
list.add(file);
} catch (Exception ex) {
Main.warn("Error with " + line + ": " + ex.getMessage());
}
}
return list.toArray(new File[list.size()]);
} catch (IOException ex) {
Main.warn("FileDrop: IOException");
}
return new File[0];
}
// END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
private void makeDropTarget( final Component c, boolean recursive )
{
// Make drop target
final DropTarget dt = new DropTarget();
try
{ dt.addDropTargetListener( dropListener );
} // end try
catch( TooManyListenersException e )
{ Main.error(e);
Main.warn("FileDrop: Drop will not work due to previous error. Do you have another listener attached?" );
} // end catch
// Listen for hierarchy changes and remove the drop target when the parent gets cleared out.
c.addHierarchyListener( new HierarchyListener()
{ @Override
public void hierarchyChanged( HierarchyEvent evt )
{ Main.trace("FileDrop: Hierarchy changed." );
Component parent = c.getParent();
if( parent == null )
{ c.setDropTarget( null );
Main.trace("FileDrop: Drop target cleared from component." );
} // end if: null parent
else
{ new DropTarget(c, dropListener);
Main.trace("FileDrop: Drop target added to component." );
} // end else: parent not null
} // end hierarchyChanged
}); // end hierarchy listener
if( c.getParent() != null ) {
new DropTarget(c, dropListener);
}
if( recursive && (c instanceof Container ) )
{
// Get the container
Container cont = (Container) c;
// Get it's components
Component[] comps = cont.getComponents();
// Set it's components as listeners also
for (Component comp : comps) {
makeDropTarget( comp, recursive);
}
} // end if: recursively set components as listener
} // end dropListener
/** Determine if the dragged data is a file list. */
private boolean isDragOk( final DropTargetDragEvent evt )
{ boolean ok = false;
// Get data flavors being dragged
DataFlavor[] flavors = evt.getCurrentDataFlavors();
// See if any of the flavors are a file list
int i = 0;
while( !ok && i < flavors.length )
{
// BEGIN 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
// Is the flavor a file list?
final DataFlavor curFlavor = flavors[i];
if( curFlavor.equals( DataFlavor.javaFileListFlavor ) ||
curFlavor.isRepresentationClassReader()){
ok = true;
}
// END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
i++;
} // end while: through flavors
// show data flavors
if( flavors.length == 0 ) {
Main.trace("FileDrop: no data flavors." );
}
for( i = 0; i < flavors.length; i++ ) {
Main.trace(flavors[i].toString() );
}
return ok;
} // end isDragOk
/**
* Removes the drag-and-drop hooks from the component and optionally
* from the all children. You should call this if you add and remove
* components after you've set up the drag-and-drop.
* This will recursively unregister all components contained within
* <var>c</var> if <var>c</var> is a {@link java.awt.Container}.
*
* @param c The component to unregister as a drop target
* @return {@code true} if at least one item has been removed, {@code false} otherwise
*/
public static boolean remove( Component c)
{ return remove( c, true );
} // end remove
/**
* Removes the drag-and-drop hooks from the component and optionally
* from the all children. You should call this if you add and remove
* components after you've set up the drag-and-drop.
*
* @param c The component to unregister
* @param recursive Recursively unregister components within a container
* @return {@code true} if at least one item has been removed, {@code false} otherwise
*/
public static boolean remove( Component c, boolean recursive )
{ // Make sure we support dnd.
if (supportsDnD()) {
Main.trace("FileDrop: Removing drag-and-drop hooks.");
c.setDropTarget(null);
if (recursive && (c instanceof Container)) {
for (Component comp : ((Container) c).getComponents()) {
remove(comp, recursive);
}
return true;
} // end if: recursive
else return false;
} // end if: supports DnD
else return false;
} // end remove
/* ******** I N N E R I N T E R F A C E L I S T E N E R ******** */
/**
* Implement this inner interface to listen for when files are dropped. For example
* your class declaration may begin like this:
* <code>
* public class MyClass implements FileDrop.Listener
* ...
* public void filesDropped( java.io.File[] files )
* {
* ...
* } // end filesDropped
* ...
* </code>
*/
public static interface Listener {
/**
* This method is called when files have been successfully dropped.
*
* @param files An array of <tt>File</tt>s that were dropped.
*/
public abstract void filesDropped( File[] files );
} // end inner-interface Listener
/* ******** I N N E R C L A S S ******** */
/**
* At last an easy way to encapsulate your custom objects for dragging and dropping
* in your Java programs!
* When you need to create a {@link java.awt.datatransfer.Transferable} object,
* use this class to wrap your object.
* For example:
* <pre><code>
* ...
* MyCoolClass myObj = new MyCoolClass();
* Transferable xfer = new TransferableObject( myObj );
* ...
* </code></pre>
* Or if you need to know when the data was actually dropped, like when you're
* moving data out of a list, say, you can use the {@link TransferableObject.Fetcher}
* inner class to return your object Just in Time.
* For example:
* <pre><code>
* ...
* final MyCoolClass myObj = new MyCoolClass();
*
* TransferableObject.Fetcher fetcher = new TransferableObject.Fetcher()
* { public Object getObject(){ return myObj; }
* }; // end fetcher
*
* Transferable xfer = new TransferableObject( fetcher );
* ...
* </code></pre>
*
* The {@link java.awt.datatransfer.DataFlavor} associated with
* {@link TransferableObject} has the representation class
* <tt>net.iharder.dnd.TransferableObject.class</tt> and MIME type
* <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
* This data flavor is accessible via the static
* {@link #DATA_FLAVOR} property.
*
*
* <p>I'm releasing this code into the Public Domain. Enjoy.</p>
*
* @author Robert Harder
* @author rob@iharder.net
* @version 1.2
*/
public static class TransferableObject implements Transferable {
/**
* The MIME type for {@link #DATA_FLAVOR} is
* <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
*/
public static final String MIME_TYPE = "application/x-net.iharder.dnd.TransferableObject";
/**
* The default {@link java.awt.datatransfer.DataFlavor} for
* {@link TransferableObject} has the representation class
* <tt>net.iharder.dnd.TransferableObject.class</tt>
* and the MIME type
* <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
*/
public static final DataFlavor DATA_FLAVOR =
new DataFlavor( FileDrop.TransferableObject.class, MIME_TYPE );
private Fetcher fetcher;
private Object data;
private DataFlavor customFlavor;
/**
* Creates a new {@link TransferableObject} that wraps <var>data</var>.
* Along with the {@link #DATA_FLAVOR} associated with this class,
* this creates a custom data flavor with a representation class
* determined from <code>data.getClass()</code> and the MIME type
* <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
*
* @param data The data to transfer
*/
public TransferableObject( Object data )
{ this.data = data;
this.customFlavor = new DataFlavor( data.getClass(), MIME_TYPE );
} // end constructor
/**
* Creates a new {@link TransferableObject} that will return the
* object that is returned by <var>fetcher</var>.
* No custom data flavor is set other than the default
* {@link #DATA_FLAVOR}.
*
* @see Fetcher
* @param fetcher The {@link Fetcher} that will return the data object
*/
public TransferableObject( Fetcher fetcher )
{ this.fetcher = fetcher;
} // end constructor
/**
* Creates a new {@link TransferableObject} that will return the
* object that is returned by <var>fetcher</var>.
* Along with the {@link #DATA_FLAVOR} associated with this class,
* this creates a custom data flavor with a representation class <var>dataClass</var>
* and the MIME type
* <tt>application/x-net.iharder.dnd.TransferableObject</tt>.
*
* @see Fetcher
* @param dataClass The {@link java.lang.Class} to use in the custom data flavor
* @param fetcher The {@link Fetcher} that will return the data object
*/
public TransferableObject(Class<?> dataClass, Fetcher fetcher )
{ this.fetcher = fetcher;
this.customFlavor = new DataFlavor( dataClass, MIME_TYPE );
} // end constructor
/**
* Returns the custom {@link java.awt.datatransfer.DataFlavor} associated
* with the encapsulated object or <tt>null</tt> if the {@link Fetcher}
* constructor was used without passing a {@link java.lang.Class}.
*
* @return The custom data flavor for the encapsulated object
*/
public DataFlavor getCustomDataFlavor()
{ return customFlavor;
} // end getCustomDataFlavor
/* ******** T R A N S F E R A B L E M E T H O D S ******** */
/**
* Returns a two- or three-element array containing first
* the custom data flavor, if one was created in the constructors,
* second the default {@link #DATA_FLAVOR} associated with
* {@link TransferableObject}, and third the
* {@link java.awt.datatransfer.DataFlavor#stringFlavor}.
*
* @return An array of supported data flavors
*/
@Override
public DataFlavor[] getTransferDataFlavors()
{
if( customFlavor != null )
return new DataFlavor[]
{ customFlavor,
DATA_FLAVOR,
DataFlavor.stringFlavor
}; // end flavors array
else
return new DataFlavor[]
{ DATA_FLAVOR,
DataFlavor.stringFlavor
}; // end flavors array
} // end getTransferDataFlavors
/**
* Returns the data encapsulated in this {@link TransferableObject}.
* If the {@link Fetcher} constructor was used, then this is when
* the {@link Fetcher#getObject getObject()} method will be called.
* If the requested data flavor is not supported, then the
* {@link Fetcher#getObject getObject()} method will not be called.
*
* @param flavor The data flavor for the data to return
* @return The dropped data
*/
@Override
public Object getTransferData( DataFlavor flavor )
throws UnsupportedFlavorException, IOException
{
// Native object
if( flavor.equals( DATA_FLAVOR ) )
return fetcher == null ? data : fetcher.getObject();
// String
if( flavor.equals( DataFlavor.stringFlavor ) )
return fetcher == null ? data.toString() : fetcher.getObject().toString();
// We can't do anything else
throw new UnsupportedFlavorException(flavor);
} // end getTransferData
/**
* Returns <tt>true</tt> if <var>flavor</var> is one of the supported
* flavors. Flavors are supported using the <code>equals(...)</code> method.
*
* @param flavor The data flavor to check
* @return Whether or not the flavor is supported
*/
@Override
public boolean isDataFlavorSupported( DataFlavor flavor )
{
// Native object
if( flavor.equals( DATA_FLAVOR ) )
return true;
// String
if( flavor.equals( DataFlavor.stringFlavor ) )
return true;
// We can't do anything else
return false;
} // end isDataFlavorSupported
/* ******** I N N E R I N T E R F A C E F E T C H E R ******** */
/**
* Instead of passing your data directly to the {@link TransferableObject}
* constructor, you may want to know exactly when your data was received
* in case you need to remove it from its source (or do anyting else to it).
* When the {@link #getTransferData getTransferData(...)} method is called
* on the {@link TransferableObject}, the {@link Fetcher}'s
* {@link #getObject getObject()} method will be called.
*
* @author Robert Harder
*/
public static interface Fetcher
{
/**
* Return the object being encapsulated in the
* {@link TransferableObject}.
*
* @return The dropped object
*/
public abstract Object getObject();
} // end inner interface Fetcher
} // end class TransferableObject
} // end class FileDrop