protected void doExportData() { FileDialog dialog = new FileDialog(this, "Export Data File...", FileDialog.SAVE); dialog.setVisible(true); if (dialog.getFile() != null) { File file = new File(dialog.getDirectory(), dialog.getFile()); Writer writer = null; try { writer = new PrintWriter(file); treesPanel.writeDataFile(writer); writer.close(); } catch (IOException ioe) { JOptionPane.showMessageDialog( this, "Error writing data file: " + ioe.getMessage(), "Export Error", JOptionPane.ERROR_MESSAGE); } } }