if (clipboard == null) {  Toolkit.getDefaultToolkit().beep(); return; }
    public void actionPerformed(ActionEvent event)    {      JComponent component = (JComponent) event.getSource();      TransferHandler transferHandler = component.getTransferHandler();      Clipboard clipboard = getClipboard(component);      if (command.equals(COMMAND_COPY))	transferHandler.exportToClipboard(component, clipboard, COPY);      else if (command.equals(COMMAND_CUT))	transferHandler.exportToClipboard(component, clipboard, MOVE);      else if (command.equals(COMMAND_PASTE))	{	  Transferable transferable = clipboard.getContents(null);	  if (transferable != null)	    transferHandler.importData(component, transferable);	}    }