How do i update a JTextfield from a file in Java

Question

I have a program that looks into a single Notepad file which contains information similar to:

Cardiff : 3245658
Bristol : 4726485
Manchester : 4728945

These places and numbers are coming out of a automatic system, and the numbers change every 20 seconds or so. I need to create a loop (I'm guessing) so that when the numbers change, my program will look back into the notepad file and update the number in the JTextField

If this isn't clear please ask questions.

P.S. I have already created the program so that it looks into the file, gets the information needs and puts it in the correct place, using an Arraylist,

All I need help with is how to make the code automatically update when there is a change in the file, and I need to do this without using any sort of Jbuttons, it just needs to do it by itself.

My whole code as it stands

package window;

import java.awt.Color;
import java.awt.EventQueue;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class MapTest {

    private JFrame frame;
    private JTextField txtCardiff;
    private JTextField txtBristol;
    private JTextField txtSheffield;
    private JTextField txtDerby;
    private JTextField txtGlasgow;
    private JTextField txtFalkirk;
    private JTextField txtNewcastle;
    private JTextField txtLeeds;
    private JTextField txtPreston;
    private JTextField txtManchester;
    private JTextField txtWolverhampton;
    private JTextField txtBirmingham;
    private JTextField txtMiltonKeynes;
    private JTextField txtPeterborough;
    private JTextField txtColindale;
    private JTextField txtStepneyGreen;
    private JTextField txtSlough;
    private JTextField txtFaraday;
    private JTextField txtGuildford;
    private JTextField txtSouthbank;
    BufferedReader CSVFile = new BufferedReader(new FileReader(Filepath);
    ArrayList<String> csv = new ArrayList<String>();

    private final ScheduledExecutorService scheduler =
               Executors.newScheduledThreadPool(1);

    /** * Launch the application. */
    public static void main(String[] args) {
         try {
                UIManager.setLookAndFeel(
                            UIManager.getSystemLookAndFeelClassName());

            } catch (ClassNotFoundException e1) {
                e1.printStackTrace();

            } catch (InstantiationException e1) {
                e1.printStackTrace();

            } catch (IllegalAccessException e1) {
                e1.printStackTrace();

            } catch (UnsupportedLookAndFeelException e1) {
                e1.printStackTrace();
            }
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    MapTest window = new MapTest();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });

    }

    /**
     * Create the application.
     * 
     * @throws IOException
     */
    public MapTest() throws IOException {
        try {
            initialize();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

    /**
     * Initialise the contents of the frame.
     * 
     * @param output
     * @throws IOException
     */

    private void initialize() throws IOException {


                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());
                csv.add(CSVFile.readLine());

                System.out.println(csv.get(0));
                System.out.println(csv.get(1));
                System.out.println(csv.get(2));
                System.out.println(csv.get(3));
                System.out.println(csv.get(4));
                System.out.println(csv.get(5));
                System.out.println(csv.get(6));
                System.out.println(csv.get(7));
                System.out.println(csv.get(8));
                System.out.println(csv.get(9));
                System.out.println(csv.get(10));
                System.out.println(csv.get(11));
                System.out.println(csv.get(12));
                System.out.println(csv.get(13));
                System.out.println(csv.get(14));
                System.out.println(csv.get(15));
                System.out.println(csv.get(16));
                System.out.println(csv.get(17));
                System.out.println(csv.get(18));
                System.out.println(csv.get(19));
                // above system.out's are to check to see if it was reading the right line


        frame = new JFrame();
        frame.setBounds(0, 0, 1000, 1086);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);
        frame.setBackground(Color.CYAN);

        txtCardiff = new JTextField();
        txtCardiff.setText(csv.get(0));
        txtCardiff.setBackground(Color.GREEN);
        txtCardiff.setBounds(305, 699, 102, 20);
        frame.getContentPane().add(txtCardiff);
        txtCardiff.setColumns(10);

        txtBristol = new JTextField();
        txtBristol.setText(csv.get(1));
        txtBristol.setBackground(Color.GREEN);
        txtBristol.setBounds(416, 780, 102, 20);
        frame.getContentPane().add(txtBristol);
        txtBristol.setColumns(10);

        txtSheffield = new JTextField();
        txtSheffield.setText(csv.get(2));
        txtSheffield.setBackground(Color.GREEN);
        txtSheffield.setBounds(517, 356, 110, 20);
        frame.getContentPane().add(txtSheffield);
        txtSheffield.setColumns(10);

        txtDerby = new JTextField();
        txtDerby.setText(csv.get(3));
        txtDerby.setBackground(Color.GREEN);
        txtDerby.setBounds(582, 451, 90, 20);
        frame.getContentPane().add(txtDerby);
        txtDerby.setColumns(10);

        txtGlasgow = new JTextField();// makes the textfield
        txtGlasgow.setText(csv.get(4)); 
        txtGlasgow.setBackground(Color.GREEN); 
        txtGlasgow.setBounds(250, 94, 102, 20);
        frame.getContentPane().add(txtGlasgow);
        txtGlasgow.setColumns(10);

        txtFalkirk = new JTextField();
        txtFalkirk.setText(csv.get(5));
        txtFalkirk.setColumns(10);
        txtFalkirk.setBackground(Color.GREEN);
        txtFalkirk.setBounds(331, 41, 102, 20);
        frame.getContentPane().add(txtFalkirk);

        txtNewcastle = new JTextField();
        txtNewcastle.setText(csv.get(6));
        txtNewcastle.setColumns(10);
        txtNewcastle.setBackground(Color.GREEN);
        txtNewcastle.setBounds(424, 141, 111, 20);
        frame.getContentPane().add(txtNewcastle);

        txtLeeds = new JTextField();
        txtLeeds.setText(csv.get(7));
        txtLeeds.setColumns(10);
        txtLeeds.setBackground(Color.GREEN);
        txtLeeds.setBounds(481, 244, 102, 20);
        frame.getContentPane().add(txtLeeds);

        txtPreston = new JTextField();
        txtPreston.setText(csv.get(8));
        txtPreston.setColumns(10);
        txtPreston.setBackground(Color.GREEN);
        txtPreston.setBounds(356, 221, 102, 20);
        frame.getContentPane().add(txtPreston);

        txtManchester = new JTextField();
        txtManchester.setText(csv.get(9));
        txtManchester.setColumns(10);
        txtManchester.setBackground(Color.GREEN);
        txtManchester.setBounds(394, 394, 124, 20);
        frame.getContentPane().add(txtManchester);

        txtWolverhampton = new JTextField();
        txtWolverhampton.setText(csv.get(10));
        txtWolverhampton.setColumns(10);
        txtWolverhampton.setBackground(Color.GREEN);
        txtWolverhampton.setBounds(360, 486, 153, 20);
        frame.getContentPane().add(txtWolverhampton);

        txtBirmingham = new JTextField();
        txtBirmingham.setText(csv.get(11));
        txtBirmingham.setColumns(10);
        txtBirmingham.setBackground(Color.GREEN);
        txtBirmingham.setBounds(424, 553, 128, 20);
        frame.getContentPane().add(txtBirmingham);

        txtMiltonKeynes = new JTextField();
        txtMiltonKeynes.setText(csv.get(12));
        txtMiltonKeynes.setColumns(10);
        txtMiltonKeynes.setBackground(Color.GREEN);
        txtMiltonKeynes.setBounds(474, 604, 135, 20);
        frame.getContentPane().add(txtMiltonKeynes);

        txtPeterborough = new JTextField();
        txtPeterborough.setText(csv.get(13));
        txtPeterborough.setColumns(10);
        txtPeterborough.setBackground(Color.GREEN);
        txtPeterborough.setBounds(655, 576, 135, 20);
        frame.getContentPane().add(txtPeterborough);

        txtColindale = new JTextField();
        txtColindale.setText(csv.get(14));
        txtColindale.setColumns(10);
        txtColindale.setBackground(Color.GREEN);
        txtColindale.setBounds(541, 699, 107, 20);
        frame.getContentPane().add(txtColindale);

        txtStepneyGreen = new JTextField();
        txtStepneyGreen.setText(csv.get(15));
        txtStepneyGreen.setColumns(10);
        txtStepneyGreen.setBackground(Color.GREEN);
        txtStepneyGreen.setBounds(667, 699, 137, 20);
        frame.getContentPane().add(txtStepneyGreen);

        txtSlough = new JTextField();
        txtSlough.setText(csv.get(16));
        txtSlough.setColumns(10);
        txtSlough.setBackground(Color.GREEN);
        txtSlough.setBounds(525, 756, 102, 20);
        frame.getContentPane().add(txtSlough);

        txtFaraday = new JTextField();
        txtFaraday.setText(csv.get(17));
        txtFaraday.setColumns(10);
        txtFaraday.setBackground(Color.GREEN);
        txtFaraday.setBounds(650, 756, 102, 20);
        frame.getContentPane().add(txtFaraday);

        txtGuildford = new JTextField();
        txtGuildford.setText(csv.get(18));
        txtGuildford.setColumns(10);
        txtGuildford.setBackground(Color.GREEN);
        txtGuildford.setBounds(525, 822, 102, 20);
        frame.getContentPane().add(txtGuildford);

        txtSouthbank = new JTextField();
        txtSouthbank.setText(csv.get(19));
        txtSouthbank.setColumns(10);
        txtSouthbank.setBackground(Color.GREEN);
        txtSouthbank.setBounds(655, 807, 115, 20);
        frame.getContentPane().add(txtSouthbank);

        JLabel lblNewLabel = new JLabel("New label");
        lblNewLabel.setForeground(Color.BLACK);
        lblNewLabel.setBackground(Color.BLACK);
        lblNewLabel
                .setIcon(new ImageIcon(
                        "FilePath
        lblNewLabel.setBounds(33, 11, 890, 1086);
        frame.getContentPane().add(lblNewLabel);
    }
}

Hello All, this might be a duplicate, but no need of downvote. +1 from me to remove the down vote — PeakGen, Mar 06 '13 at 17:39

score 0 · Answer 1 · answered Mar 05 '13 at 20:03

0

This is an easy task. I don't know anything about WatchService, but this can be done using the Timer as well. Create a Timer which will seek the notepad for every 20 seconds. You have to programatically check whether the numbers has been changed or not.

answered Mar 05 '13 at 20:03

PeakGen

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How would you code the Timer ? ive never used it before, thanks for any more help you can give me – Wilson Mar 06 '13 at 08:53
@Wilson: Schedule a task using the Timer. This contains an example http://stackoverflow.com/questions/4044729/java-timer-task-schedule – PeakGen Mar 06 '13 at 17:33

How do i update a JTextfield from a file in Java

1 Answers1