swing中实现组织机构图拖拽功能的问题

import java.awt.BorderLayout;  
import java.awt.Dimension;  
import java.awt.Rectangle;  
import java.awt.datatransfer.DataFlavor;  
import java.awt.datatransfer.UnsupportedFlavorException;  
import java.awt.event.ActionEvent;  
import java.awt.event.ActionListener;  
import java.awt.event.MouseAdapter;  
import java.awt.event.MouseEvent;  
import java.io.IOException;  

import javax.swing.BorderFactory;  
import javax.swing.Box;  
import javax.swing.BoxLayout;  
import javax.swing.DefaultListModel;  
import javax.swing.DropMode;  
import javax.swing.JCheckBoxMenuItem;  
import javax.swing.JFrame;  
import javax.swing.JLabel;  
import javax.swing.JList;  
import javax.swing.JMenu;  
import javax.swing.JMenuBar;  
import javax.swing.JMenuItem;  
import javax.swing.JPanel;  
import javax.swing.JScrollPane;  
import javax.swing.JTable;  
import javax.swing.ListSelectionModel;  
import javax.swing.SwingUtilities;  
import javax.swing.TransferHandler;  
import javax.swing.UIManager;  
import javax.swing.table.DefaultTableModel;  

public class FillViewportHeightDemo extends JFrame implements ActionListener {  

  private DefaultListModel model = new DefaultListModel();  
  private int count = 0;  
  private JTable table;  
  private JCheckBoxMenuItem fillBox;  
  private DefaultTableModel tableModel;  

  private static String getNextString(int count) {  
    StringBuffer buf = new StringBuffer();  
    for (int i = 0; i < 5; i++) {  
      buf.append(String.valueOf(count));  
      buf.append(",");  
    }  

    // remove last newline  
    buf.deleteCharAt(buf.length() - 1);  
    return buf.toString();  
  }  

  private static DefaultTableModel getDefaultTableModel() {  
    String[] cols = { "Foo", "Toto", "Kala", "Pippo", "Boing" };  
    return new DefaultTableModel(null, cols);  
  }  

  public FillViewportHeightDemo() {  
    super("Empty Table DnD Demo");  

    tableModel = getDefaultTableModel();  
    table = new JTable(tableModel);  
    table.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);  
    table.setDropMode(DropMode.INSERT_ROWS);  

    //增加表格拖动事件  
    table.setTransferHandler(new TransferHandler() {  

      //指示一个组件在实际尝试导入给定数据 flavor 的集合之前是否接受导入。  
      public boolean canImport(TransferSupport support) {  
        // for the demo, we'll only support drops (not clipboard paste)  
        if (!support.isDrop()) {  
          return false;  
        }  

        // we only import Strings  
        if (!support.isDataFlavorSupported(DataFlavor.stringFlavor)) {  
          return false;  
        }  

        return true;  
      }  

      //导致从剪贴板或 DND 放置操作向组件的传输。  
      public boolean importData(TransferSupport support) {  
        // if we can't handle the import, say so  
        if (!canImport(support)) {  
          return false;  
        }  

        // fetch the drop location  
        JTable.DropLocation dl = (JTable.DropLocation) support  
            .getDropLocation();  

        int row = dl.getRow();  

        // fetch the data and bail if this fails  
        String data;  
        try {  
          //获得拖动数据  
          data = (String) support.getTransferable().getTransferData(  
              DataFlavor.stringFlavor);  
        } catch (UnsupportedFlavorException e) {  
          return false;  
        } catch (IOException e) {  
          return false;  
        }  

        String[] rowData = data.split(",");  
         
        //将数据增加到表格中  
        tableModel.insertRow(row, rowData);  

        Rectangle rect = table.getCellRect(row, 0, false);  
        if (rect != null) {  
          table.scrollRectToVisible(rect);  
        }  

        // demo stuff - remove for blog  
        model.removeAllElements();  
        model.insertElementAt(getNextString(count++), 0);  
        // end demo stuff  

        return true;  
      }  
    });  

    JList dragFrom = new JList(model);  
    dragFrom.setFocusable(false);  
    dragFrom.setPrototypeCellValue(getNextString(100));  
    model.insertElementAt(getNextString(count++), 0);  
    dragFrom.setDragEnabled(true);  
    dragFrom.setBorder(BorderFactory.createLoweredBevelBorder());  

    dragFrom.addMouseListener(new MouseAdapter() {  
      public void mouseClicked(MouseEvent me) {  
        if (SwingUtilities.isLeftMouseButton(me) && me.getClickCount() % 2 == 0) {  
          String text = (String) model.getElementAt(0);  
          String[] rowData = text.split(",");  
          tableModel.insertRow(table.getRowCount(), rowData);  
          model.removeAllElements();  
          model.insertElementAt(getNextString(count++), 0);  
        }  
      }  
    });  

    JPanel p = new JPanel();  
    p.setLayout(new BoxLayout(p, BoxLayout.X_AXIS));  
    JPanel wrap = new JPanel();  
    wrap.add(new JLabel("Drag from here:"));  
    wrap.add(dragFrom);  
    p.add(Box.createHorizontalStrut(4));  
    p.add(Box.createGlue());  
    p.add(wrap);  
    p.add(Box.createGlue());  
    p.add(Box.createHorizontalStrut(4));  
    getContentPane().add(p, BorderLayout.NORTH);  

    JScrollPane sp = new JScrollPane(table);  
    getContentPane().add(sp, BorderLayout.CENTER);  
    fillBox = new JCheckBoxMenuItem("Fill Viewport Height");  
    fillBox.addActionListener(this);  

    JMenuBar mb = new JMenuBar();  
    JMenu options = new JMenu("Options");  
    mb.add(options);  
    setJMenuBar(mb);  

    JMenuItem clear = new JMenuItem("Reset");  
    clear.addActionListener(this);  
    options.add(clear);  
    options.add(fillBox);  

    getContentPane().setPreferredSize(new Dimension(260, 180));  
  }  

  public void actionPerformed(ActionEvent ae) {  
    if (ae.getSource() == fillBox) {  
      table.setFillsViewportHeight(fillBox.isSelected());  
    } else {  
      tableModel.setRowCount(0);  
      count = 0;  
      model.removeAllElements();  
      model.insertElementAt(getNextString(count++), 0);  
    }  
  }  

  private static void createAndShowGUI() {  
    // Create and set up the window.  
    FillViewportHeightDemo test = new FillViewportHeightDemo();  
    test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  

    // Display the window.  
    test.pack();  
    test.setVisible(true);  
  }  

  public static void main(String[] args) {  
    SwingUtilities.invokeLater(new Runnable() {  
      public void run() {  
        // Turn off metal's use of bold fonts  
        UIManager.put("swing.boldMetal", Boolean.FALSE);  
        createAndShowGUI();  
      }  
    });  
  }  
}