source: trunk/src/org/expeditee/gio/swing/SwingDragAndDropManager.java@ 1436

package org.expeditee.gio.swing;

import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.File;
import java.io.IOException;
import java.util.List;

import javax.swing.TransferHandler;

import org.expeditee.Util;
import org.expeditee.core.Point;
import org.expeditee.gio.DragAndDropManager;
import org.expeditee.gui.DisplayController;
import org.expeditee.gui.MessageBay;

public class SwingDragAndDropManager extends DragAndDropManager {

        /** Singleton instance. */
        private static SwingDragAndDropManager _instance = null;
        
        /** Singleton instantiator. */
        public static SwingDragAndDropManager getInstance()
        {
                if (_instance == null) _instance = new SwingDragAndDropManager();
                
                return _instance;
        }

        // GNOME and KDE desktops have a specialized way of DNDing files
        private DataFlavor _URIListDataflavorString;

        private DataFlavor _URIListDataflavorCharArray;
        
        private ExpediteeTransferHandler _transferHandler;
        
        private SwingDragAndDropManager()
        {
                // Wire up the transfer handler
                if (Util.isMinimumVersion6()) {
                        _transferHandler = new ExpediteeTransferHandler();
                        SwingMiscManager.getIfUsingSwingGraphicsManager().setTransferHandler(_transferHandler);
                } else {
                        System.err.println("Upgrade to a (minimum) of Java 1.6 to enable drag and drop support in Expeditee");
                }
                
                try {
                        _URIListDataflavorString = new DataFlavor("text/uri-list;class=java.lang.String");
                        _URIListDataflavorCharArray = new DataFlavor("text/uri-list;class=\"[C\"");
                        
                // This would never happen, java.lang.String is always present
                } catch (ClassNotFoundException e) {
                        e.printStackTrace();
                        _URIListDataflavorString = null;
                }
                assert (_URIListDataflavorString != null);
                assert (_URIListDataflavorCharArray != null);
        }
        
        private class ExpediteeTransferHandler extends TransferHandler {
                
                /** Auto-generated serialisation ID#. */
                private static final long serialVersionUID = 6552099431345591756L;

                @Override
                public boolean canImport(TransferSupport support) {

                        if (!support.isDrop()) {
                                return false;
                        }

                        // we only import Strings
                        if (    support.isDataFlavorSupported(DataFlavor.stringFlavor) ||
                                        support.isDataFlavorSupported(DataFlavor.javaFileListFlavor) ||
                                        support.isDataFlavorSupported(_URIListDataflavorString) ||
                                        support.isDataFlavorSupported(_URIListDataflavorCharArray))
                        {
                                // check if the source actions (a bitwise-OR of supported actions)
                                // contains the COPY action
                                boolean copySupported = (COPY & support.getSourceDropActions()) == COPY;
                                if (copySupported) {
                                        support.setDropAction(COPY);
                                        return true;
                                }
                        }

                        // Reject transfer
                        return false;
                }
                
                @Override
                public boolean importData(TransferSupport support)
                {
                        if (!canImport(support) || DisplayController.getCurrentFrame() == null) return false;

                        // Get the location of where to drop the import
                        DropLocation location = support.getDropLocation();

                        // Convert it into expeditee space
                        Point expediteeDropPoint = SwingConversions.fromSwingPoint(location.getDropPoint());

                        try {

                                // The list of data flavors are ordered by most rich to least ..
                                // keep trying until first
                                // data flavor recognized.
                                DataFlavor[] flavors = support.getTransferable().getTransferDataFlavors();
                                for (DataFlavor df : flavors) {

                                        System.out.println(df);

                                        if (df == DataFlavor.stringFlavor) { // import as text item

                                                String str = (String) support.getTransferable().getTransferData(DataFlavor.stringFlavor);

                                                if (str != null && str.length() > 0) {
                                                        importString(str, expediteeDropPoint, false);
                                                        return true;
                                                }

                                        // Usually Windows and MAC enviroments
                                        // Windows has other random types...
                                        } else if (df == DataFlavor.javaFileListFlavor || df.getSubType().equals("x-java-file-list")) {

                                                List<? extends File> files = (List<? extends File>) support.getTransferable().getTransferData(DataFlavor.javaFileListFlavor);

                                                importFileList(files, expediteeDropPoint, false);

                                                return true;

                                        // Usually GNOME and KDE enviroments
                                        } else if (df.equals(_URIListDataflavorString)) {

                                                String data = (String) support.getTransferable().getTransferData(_URIListDataflavorString);

                                                List<File> files = textURIListToFileList(data);

                                                importFileList(files, expediteeDropPoint, false);

                                                return true;

                                        } else if (df.equals(_URIListDataflavorCharArray)) {

                                                char[] data = (char[]) support.getTransferable().getTransferData(_URIListDataflavorCharArray);

                                                String uriString = new String(data);

                                                List<File> files = textURIListToFileList(uriString);

                                                importFileList(files, expediteeDropPoint, false);

                                                return true;
                                        }
                                }

                        } catch (UnsupportedFlavorException e) {
                                MessageBay.displayMessage("Drag and drop for that type of data is not supported");
                        } catch (IOException e) {
                                e.printStackTrace();
                                MessageBay.displayMessage("Failed to import data in Expeditee");
                        }

                        return false;
                }
                
        }

}