bcv-vf/src/main/java/the/bytecode/club/bytecodeviewer/util/FileDrop.java

package the.bytecode.club.bytecodeviewer.util;

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.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.PrintStream;
import java.io.Reader;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.border.Border;
import the.bytecode.club.bytecodeviewer.BytecodeViewer;

/***************************************************************************
 * Bytecode Viewer (BCV) - Java & Android Reverse Engineering Suite        *
 * Copyright (C) 2014 Kalen 'Konloch' Kinloch - http://bytecodeviewer.com  *
 *                                                                         *
 * This program is free software: you can redistribute it and/or modify    *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation, either version 3 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
 ***************************************************************************/

/**
 * This class makes it easy to drag and drop files from the operating system to
 * a Java program. Any <tt>Component</tt> can be dropped onto, but only
 * <tt>JComponent</tt>s will indicate the drop event with a changed
 * border.
 *
 * 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:
 *
 *      JPanel myPanel = new JPanel();
 *      new FileDrop( myPanel, new FileDrop.Listener()
 *      {   public void filesDropped( File[] files )
 *          {
 *              // handle file drop
 *              ...
 *          }   // end filesDropped
 *      }); // end FileDrop.Listener
 *
 * You can specify the border that will appear when files are being dragged by
 * calling the constructor with a <tt>Border</tt>. Only
 * <tt>JComponent</tt>s will show any indication with a border.
 *
 * 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.
 * 
 * I'm releasing this code into the Public Domain. Enjoy.
 *
 * <em>Original author: Robert Harder, rharder@usa.net</em>
 *
 * 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.
 *
 * @author Robert Harder
 * @author rharder@users.sf.net
 * @version 1.0.1
 */
@SuppressWarnings({"rawtypes", "unused", "unchecked"})
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 final Color defaultBorderColor = new Color(0f,
            0f, 1f, 0.25f);

    /**
     * Constructs a {@link FileDrop} with a default light-blue border and, if
     * <var>c</var> is a {@link Container}, recursively sets all
     * elements contained within as drop targets, though only the top level
     * container will change borders.
     *
     * @param c        Component on which files will be dropped.
     * @param listener Listens for <tt>filesDropped</tt>.
     * @since 1.0
     */
    public FileDrop(final Component c, final Listener listener) {
        this(null, // Logging stream
                c, // Drop target
                BorderFactory.createMatteBorder(2, 2, 2, 2,
                        defaultBorderColor), // Drag border
                true, // Recursive
                listener);
    } // end constructor

    /**
     * Constructor with a default border and the option to recursively set drop
     * targets. If your component is a <tt>Container</tt>, then each of
     * its children components will also listen for drops, though only the
     * parent will change borders.
     *
     * @param c         Component on which files will be dropped.
     * @param recursive Recursively set children as drop targets.
     * @param listener  Listens for <tt>filesDropped</tt>.
     * @since 1.0
     */
    public FileDrop(final Component c, final boolean recursive,
                    final Listener listener) {
        this(null, // Logging stream
                c, // Drop target
                BorderFactory.createMatteBorder(2, 2, 2, 2,
                        defaultBorderColor), // Drag border
                recursive, // Recursive
                listener);
    } // end constructor

    /**
     * Constructor with a default 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 out      PrintStream to record debugging info or null for no debugging.
     * @param c        Component on which files will be dropped.
     * @param listener Listens for <tt>filesDropped</tt>.
     * @since 1.0
     */
    public FileDrop(final PrintStream out, final Component c,
                    final Listener listener) {
        this(out, // Logging stream
                c, // Drop target
                BorderFactory.createMatteBorder(2, 2, 2, 2,
                        defaultBorderColor), false, // Recursive
                listener);
    } // end constructor

    /**
     * Constructor with a default border, debugging optionally turned on and the
     * option to recursively set drop targets. If your component is a
     * <tt>Container</tt>, then each of its children components will
     * also listen for drops, though only the parent will change borders. 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 out       PrintStream to record debugging info or null for no debugging.
     * @param c         Component on which files will be dropped.
     * @param recursive Recursively set children as drop targets.
     * @param listener  Listens for <tt>filesDropped</tt>.
     * @since 1.0
     */
    public FileDrop(final PrintStream out, final Component c,
                    final boolean recursive, final Listener listener) {
        this(out, // Logging stream
                c, // Drop target
                BorderFactory.createMatteBorder(2, 2, 2, 2,
                        defaultBorderColor), // Drag border
                recursive, // Recursive
                listener);
    } // end constructor

    /**
     * Constructor with a specified border
     *
     * @param c          Component on which files will be dropped.
     * @param dragBorder Border to use on <tt>JComponent</tt> when dragging occurs.
     * @param listener   Listens for <tt>filesDropped</tt>.
     * @since 1.0
     */
    public FileDrop(final Component c,
                    final Border dragBorder, final Listener listener) {
        this(null, // Logging stream
                c, // Drop target
                dragBorder, // Drag border
                false, // Recursive
                listener);
    } // end constructor

    /**
     * Constructor with a specified border and the option to recursively set
     * drop targets. If your component is a <tt>Container</tt>, then
     * each of its children components will also listen for drops, though only
     * the parent will change borders.
     *
     * @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>.
     * @since 1.0
     */
    public FileDrop(final Component c,
                    final Border dragBorder,
                    final boolean recursive, final Listener listener) {
        this(null, c, dragBorder, recursive, listener);
    } // end constructor

    /**
     * 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 out        PrintStream to record debugging info or null for no debugging.
     * @param c          Component on which files will be dropped.
     * @param dragBorder Border to use on <tt>JComponent</tt> when dragging occurs.
     * @param listener   Listens for <tt>filesDropped</tt>.
     * @since 1.0
     */
    public FileDrop(final PrintStream out, final Component c,
                    final Border dragBorder, final Listener listener) {
        this(out, // Logging stream
                c, // Drop target
                dragBorder, // Drag border
                false, // Recursive
                listener);
    } // end constructor

    /**
     * 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 out        PrintStream to record debugging info or null for no debugging.
     * @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>.
     * @since 1.0
     */
    public FileDrop(final PrintStream out, 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(final DropTargetDragEvent evt) {
                    log(out, "FileDrop: dragEnter event.");

                    // Is this an acceptable drag event?
                    if (isDragOk(out, evt)) {
                        // If it's a Swing component, set its border
                        if (c instanceof JComponent) {
                            final JComponent jc = (JComponent) c;
                            normalBorder = jc.getBorder();
                            log(out, "FileDrop: normal border saved.");
                            jc.setBorder(dragBorder);
                            log(out, "FileDrop: drag border set.");
                        } // end if: JComponent

                        // Acknowledge that it's okay to enter
                        // evt.acceptDrag(
                        // DnDConstants.ACTION_COPY_OR_MOVE );
                        evt.acceptDrag(DnDConstants.ACTION_COPY);
                        log(out, "FileDrop: event accepted.");
                    } // end if: drag ok
                    else { // Reject the drag event
                        evt.rejectDrag();
                        log(out, "FileDrop: event rejected.");
                    } // end else: drag not ok
                } // end dragEnter

                @Override
                public void dragOver(final DropTargetDragEvent evt) { // This
                    // is
                    // called
                    // continually
                    // as
                    // long
                    // as
                    // the
                    // mouse
                    // is
                    // over
                    // the
                    // drag
                    // target.
                } // end dragOver

                @Override
                public void drop(final DropTargetDropEvent evt) {
                    log(out, "FileDrop: drop event.");
                    try { // Get whatever was dropped
                        final Transferable tr = evt
                                .getTransferable();

                        // Is it a file list?
                        if (tr.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
                            // Say we'll take it.
                            // evt.acceptDrop (
                            // DnDConstants.ACTION_COPY_OR_MOVE );
                            evt.acceptDrop(DnDConstants.ACTION_COPY);
                            log(out, "FileDrop: file list accepted.");

                            // Get a useful list
                            final java.util.List fileList = (java.util.List) tr
                                    .getTransferData(DataFlavor.javaFileListFlavor);
                            final java.util.Iterator iterator = fileList
                                    .iterator();

                            // Convert list to array
                            final File[] filesTemp = new File[fileList
                                    .size()];
                            fileList.toArray(filesTemp);

                            // Alert listener to drop.
                            if (listener != null) {
                                listener.filesDropped(filesTemp);
                            }

                            // Mark that drop is completed.
                            evt.getDropTargetContext().dropComplete(true);
                            log(out, "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.
                            final DataFlavor[] flavors = tr
                                    .getTransferDataFlavors();
                            boolean handled = false;
                            for (DataFlavor flavor : flavors) {
                                if (flavor.isRepresentationClassReader()) {
                                    // Say we'll take it.
                                    // evt.acceptDrop (
                                    // DnDConstants.ACTION_COPY_OR_MOVE
                                    // );
                                    evt.acceptDrop(DnDConstants.ACTION_COPY);
                                    log(out, "FileDrop: reader accepted.");

                                    final Reader reader = flavor
                                            .getReaderForText(tr);

                                    final BufferedReader br = new BufferedReader(
                                            reader);

                                    if (listener != null) {
                                        listener.filesDropped(createFileArray(
                                                br, out));
                                    }

                                    // Mark that drop is completed.
                                    evt.getDropTargetContext().dropComplete(
                                            true);
                                    log(out, "FileDrop: drop complete.");
                                    handled = true;
                                    break;
                                }
                            }
                            if (!handled) {
                                log(out,
                                        "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 (final IOException io) {
                        log(out, "FileDrop: IOException - abort:");
                        BytecodeViewer.handleException(io);
                        evt.rejectDrop();
                    } // end catch IOException
                    catch (final UnsupportedFlavorException ufe) {
                        log(out,
                                "FileDrop: UnsupportedFlavorException - abort:");
                        BytecodeViewer.handleException(
                                ufe);
                        evt.rejectDrop();
                    } // end catch: UnsupportedFlavorException
                    finally {
                        // If it's a Swing component, reset its border
                        if (c instanceof JComponent) {
                            final JComponent jc = (JComponent) c;
                            jc.setBorder(normalBorder);
                            log(out, "FileDrop: normal border restored.");
                        } // end if: JComponent
                    } // end finally
                } // end drop

                @Override
                public void dragExit(final DropTargetEvent evt) {
                    log(out, "FileDrop: dragExit event.");
                    // If it's a Swing component, reset its border
                    if (c instanceof JComponent) {
                        final JComponent jc = (JComponent) c;
                        jc.setBorder(normalBorder);
                        log(out, "FileDrop: normal border restored.");
                    } // end if: JComponent
                } // end dragExit

                @Override
                public void dropActionChanged(
                        final DropTargetDragEvent evt) {
                    log(out, "FileDrop: dropActionChanged event.");
                    // Is this an acceptable drag event?
                    if (isDragOk(out, evt)) { // evt.acceptDrag(
                        // DnDConstants.ACTION_COPY_OR_MOVE
                        // );
                        evt.acceptDrag(DnDConstants.ACTION_COPY);
                        log(out, "FileDrop: event accepted.");
                    } // end if: drag ok
                    else {
                        evt.rejectDrag();
                        log(out, "FileDrop: event rejected.");
                    } // end else: drag not ok
                } // end dropActionChanged
            }; // end DropTargetListener

            // Make the component (and possibly children) drop targets
            makeDropTarget(out, c, recursive);
        } // end if: supports dnd
        else {
            log(out, "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;
            try {
                final Class arbitraryDndClass = Class
                        .forName("java.awt.dnd.DnDConstants");
                support = true;
            } // end try
            catch (final Throwable t) {
                support = false;
            } // end catch
            supportsDnD = support;
        } // end if: first time through
        return supportsDnD;
    } // 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(final BufferedReader bReader,
                                          final PrintStream out) {
        try {
            final java.util.List list = new java.util.ArrayList();
            java.lang.String line;
            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;
                    }

                    final File file = new File(
                            new java.net.URI(line));
                    list.add(file);
                } catch (final Exception ex) {
                    log(out, "Error with " + line + ": " + ex.getMessage());
                }
            }

            return (File[]) list.toArray(new File[0]);
        } catch (final IOException ex) {
            log(out, "FileDrop: IOException");
        }
        return new File[0];
    }

    // END 2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.

    private void makeDropTarget(final PrintStream out,
                                final Component c, final boolean recursive) {
        // Make drop target
        final DropTarget dt = new DropTarget();
        try {
            dt.addDropTargetListener(dropListener);
        } // end try
        catch (final java.util.TooManyListenersException e) {
            BytecodeViewer.handleException(e);
            log(out,
                    "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.
        // end hierarchyChanged
        c.addHierarchyListener(evt -> {
            log(out, "FileDrop: Hierarchy changed.");
            final Component parent = c.getParent();
            if (parent == null) {
                c.setDropTarget(null);
                log(out, "FileDrop: Drop target cleared from component.");
            } // end if: null parent
            else {
                new DropTarget(c, dropListener);
                log(out, "FileDrop: Drop target added to component.");
            } // end else: parent not null
        }); // end hierarchy listener
        if (c.getParent() != null) {
            new DropTarget(c, dropListener);
        }

        if (recursive && (c instanceof Container)) {
            // Get the container
            final Container cont = (Container) c;

            // Get its components
            final Component[] comps = cont.getComponents();

            // Set its components as listeners also
            for (Component comp : comps) {
                makeDropTarget(out, comp, true);
            }
        } // end if: recursively set components as listener
    } // end dropListener

    /**
     * Determine if the dragged data is a file list.
     */
    private boolean isDragOk(final PrintStream out,
                             final DropTargetDragEvent evt) {
        boolean ok = false;

        // Get data flavors being dragged
        final 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

        // If logging is enabled, show data flavors
        if (out != null) {
            if (flavors.length == 0) {
                log(out, "FileDrop: no data flavors.");
            }
            for (i = 0; i < flavors.length; i++) {
                log(out, flavors[i].toString());
            }
        } // end if: logging enabled

        return ok;
    } // end isDragOk

    /**
     * Outputs <tt>message</tt> to <tt>out</tt> if it's not null.
     */
    private static void log(final PrintStream out, final String message) { // Log
        // message
        // if
        // requested
        if (out != null) {
            out.println(message);
        }
    } // end log

    /**
     * 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 Container}.
     *
     * @param c The component to unregister as a drop target
     * @since 1.0
     */
    public static boolean remove(final Component c) {
        return remove(null, 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 out       Optional {@link PrintStream} for logging drag and drop
     *                  messages
     * @param c         The component to unregister
     * @param recursive Recursively unregister components within a container
     * @since 1.0
     */
    public static boolean remove(final PrintStream out,
                                 final Component c, final boolean recursive) { // Make sure
        // we
        // support
        // 
        if (supportsDnD()) {
            log(out, "FileDrop: Removing drag-and-drop hooks.");
            c.setDropTarget(null);
            if (recursive && (c instanceof Container)) {
                final Component[] comps = ((Container) c)
                        .getComponents();
                for (Component comp : comps) {
                    remove(out, comp, true);
                }
                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><pre>
     *      public class MyClass implements FileDrop.Listener
     *      ...
     *      public void filesDropped( File[] files )
     *      {
     *          ...
     *      }   // end filesDropped
     *      ...
     * </pre></code>
     *
     * @since 1.1
     */
    public interface Listener {

        /**
         * This method is called when files have been successfully dropped.
         *
         * @param files An array of <tt>File</tt>s that were dropped.
         * @since 1.0
         */
        void filesDropped(File[] files);

    } // end inner-interface Listener

    /* ******** I N N E R C L A S S ******** */

    /**
     * This is the event that is passed to the
     * FileDropListener#filesDropped filesDropped(...) method in your
     * FileDropListener when files are dropped onto a registered drop
     * target.
     * <p>
     * <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 Event extends java.util.EventObject {

        private static final long serialVersionUID = -2175361562828864378L;
        private final File[] files;

        /**
         * Constructs an {@link Event} with the array of files that were dropped
         * and the {@link FileDrop} that initiated the event.
         *
         * @param files The array of files that were dropped
         * @param source The event source
         * @since 1.1
         */
        public Event(final File[] files, final Object source) {
            super(source);
            this.files = files;
        } // end constructor

        /**
         * Returns an array of files that were dropped on a registered drop
         * target.
         *
         * @return array of files that were dropped
         * @since 1.1
         */
        public File[] getFiles() {
            return files;
        } // end getFiles

    } // end inner class Event

    /* ******** 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 Transferable} object, use this class to wrap
     * your object. For example:
     * <p>
     * <pre>
     * <code>
     *      ...
     *      MyCoolClass myObj = new MyCoolClass();
     *      Transferable xfer = new TransferableObject( myObj );
     *      ...
     * </code>
     * </pre>
     * <p>
     * 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:
     * <p>
     * <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>
     * <p>
     * The {@link DataFlavor} associated with
     * {@link TransferableObject} has the representation class
     * <tt>net.iharder.TransferableObject.class</tt> and MIME type
     * <tt>application/x-net.iharder.TransferableObject</tt>. This data
     * flavor is accessible via the static {@link #DATA_FLAVOR} property.
     * <p>
     * <p>
     * <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.TransferableObject</tt>.
         *
         * @since 1.1
         */
        public final static String MIME_TYPE = "application/x-net.iharder.TransferableObject";

        /**
         * The default {@link DataFlavor} for
         * {@link TransferableObject} has the representation class
         * <tt>net.iharder.TransferableObject.class</tt> and the MIME type
         * <tt>application/x-net.iharder.TransferableObject</tt>.
         *
         * @since 1.1
         */
        public final static 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.TransferableObject</tt>.
         *
         * @param data The data to transfer
         * @since 1.1
         */
        public TransferableObject(final 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}.
         *
         * @param fetcher The {@link Fetcher} that will return the data object
         * @see Fetcher
         * @since 1.1
         */
        public TransferableObject(final 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.TransferableObject</tt>.
         *
         * @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
         * @see Fetcher
         * @since 1.1
         */
        public TransferableObject(final Class dataClass, final Fetcher fetcher) {
            this.fetcher = fetcher;
            this.customFlavor = new DataFlavor(dataClass,
                    MIME_TYPE);
        } // end constructor

        /**
         * Returns the custom {@link 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
         * @since 1.1
         */
        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
         * DataFlavor.stringFlavor.
         *
         * @return An array of supported data flavors
         * @since 1.1
         */
        @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
         * @since 1.1
         */
        @Override
        public Object getTransferData(
                final DataFlavor flavor)
                throws UnsupportedFlavorException {
            // 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
         * @since 1.1
         */
        @Override
        public boolean isDataFlavorSupported(
                final DataFlavor flavor) {
            // Native object
            if (flavor.equals(DATA_FLAVOR))
                return true;

            // String
            return flavor.equals(DataFlavor.stringFlavor);

            // We can't do anything else
        } // 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
         * @version 1.1
         * @copyright 2001
         * @since 1.1
         */
        public interface Fetcher {
            /**
             * Return the object being encapsulated in the
             * {@link TransferableObject}.
             *
             * @return The dropped object
             * @since 1.1
             */
            Object getObject();
        } // end inner interface Fetcher

    } // end class TransferableObject

} // end class FileDrop