code: package swing.common;
  
  //import cic.cs.unb.ca.uup.ui.Constants;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.swing.*;
  import java.awt.*;
  import java.awt.event.ActionEvent;
  import java.awt.event.ActionListener;
  import java.io.File;
  import java.util.Vector;
  
  public class CsvPickerPane extends JPanel{
      protected static final Logger logger = LoggerFactory.getLogger(CsvPickerPane.class);
  
      private JFileChooser fileChooser;
      private TextFileFilter fileChooserFilter;
      private JComboBox<CsvFileWrapper> cmbCSVFile;
      private Vector<CsvFileWrapper> cmbCSVFileEle;
      private JButton btnBrowse;
      private JButton btnOK;
      private CsvSelect selectListener;
  
      public CsvPickerPane(Container parent) {
  
          initComponent();
  
          setLayout(new BoxLayout(this,BoxLayout.Y_AXIS));
          //setBorder(Constants.LINEBORDER);
  
          Box baseBox = Box.createVerticalBox();
  
          Box cmbBox = Box.createHorizontalBox();
  
          cmbBox.add(cmbCSVFile);
          cmbBox.add(Box.createHorizontalStrut(20));
          cmbBox.add(btnBrowse);
          cmbBox.add(Box.createHorizontalStrut(20));
          cmbBox.add(btnOK);
          cmbBox.add(Box.createHorizontalStrut(10));
  
          baseBox.add(cmbBox);
  
          add(baseBox);
      }
  
      private void initComponent(){
          fileChooser = new JFileChooser(new File(System.getProperty("user.dir")));
          fileChooserFilter = new TextFileFilter("CSV File (*.csv)",new String[]{"csv"});
          fileChooser.setFileFilter(fileChooserFilter);
          cmbCSVFileEle = new Vector<>();
          cmbCSVFile = new  JComboBox<>(cmbCSVFileEle);
          btnBrowse = new JButton("Browse");
          btnBrowse.addActionListener(mActionListener);
          btnOK = new JButton("OK");
          btnOK.addActionListener(mActionListener);
      }
  
      public void setPickerEnabled(boolean b){
          btnOK.setEnabled(b);
      }
  
      public void setFilter(CharSequence... searchCharSequences) {
          fileChooserFilter = new TextFileFilter("CSV File (*.csv)",new String[]{"csv"},searchCharSequences);
          fileChooser.setFileFilter(fileChooserFilter);
      }
  
      public void setSelectListener(CsvSelect listener) {
          selectListener = listener;
      }
  
      private ActionListener mActionListener = new ActionListener() {
  
          @Override
          public void actionPerformed(ActionEvent e) {
              switch (e.getActionCommand()) {
                  case "Browse":
                      int action = fileChooser.showOpenDialog(CsvPickerPane.this);
                      if (action == JFileChooser.APPROVE_OPTION) {
                          File f = fileChooser.getSelectedFile();
  
                          File csvFilePath;
  
                          if(f.isDirectory()) {
                              csvFilePath = f;
                          }else {
                              csvFilePath = f.getParentFile();
                          }
  
                          cmbCSVFileEle.clear();
                          cmbCSVFileEle.addAll(CsvFileWrapper.loadCSVFile(csvFilePath,fileChooserFilter.getFileNameFilter()));
  
                          cmbCSVFile.setSelectedIndex(0);
                          for(int i=0;i<cmbCSVFileEle.size();i++) {
                              CsvFileWrapper csvF = cmbCSVFileEle.get(i);
  
                              if (csvF.getFile().getPath().equals(f.getPath())) {
                                  cmbCSVFile.setSelectedIndex(i);
                                  break;
                              }
                          }
  
                      }
                      break;
                  case "OK":
  
                      CsvFileWrapper csvfile = (CsvFileWrapper) cmbCSVFile.getSelectedItem();
  
                      if (csvfile != null && selectListener != null) {
                          selectListener.onSelected(csvfile.getFile());
                      }
                      break;
              }
          }
      };
  
      public interface CsvSelect{
          void onSelected(File file);
      }
  
      private static void createAndShowGUI() {
          //Create and set up the window.
          JFrame frame = new JFrame("CsvPickerPane");
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          CsvPickerPane demopane = new CsvPickerPane(frame);
          frame.getContentPane().add(demopane);
  
          //Display the window.
          frame.pack();
          frame.setVisible(true);
      }
  
      public static void main(String[] args) {
          javax.swing.SwingUtilities.invokeLater(() -> createAndShowGUI());
      }
  
  
  }
  