Maps and Separate Classes

Question

Hi again :D hehe
Any idea how I can transfer the file reading into an empty java class say ReadFile.java. And access the Map set from the first main gui java class (im using netbeans, if this helps :D)
Thank you!
steve
p.s. the txt file it reads if the following flights.txt - e.g. aberdeen,london,50 (start,destination,cost) aberdeen,manchester,21 - london,brighton,12
    Map<String,Map<String,Integer>> flights = new HashMap<String,Map<String,Integer>>();
    private void buttonOpenFileActionPerformed(java.awt.event.ActionEvent evt) {                                              
                   // load the first line from a file into the firstlineBox textbox
        JFileChooser fileChooser = new JFileChooser();      // create a file chooser
        int returnVal = fileChooser.showOpenDialog(this); // show an open file dialogue
        if (returnVal == JFileChooser.APPROVE_OPTION) {   // was it successful (not cancelled)
            File file = fileChooser.getSelectedFile();    // if so, get selected file
            try {                                         // catch I/O errors
                FileReader fr = new FileReader(file);       // set up file reader
                LineNumberReader input = new LineNumberReader(fr); // line number reader supports readLine
                // all set up, now we can read!
            while (true) {
                    String line = input.readLine();     // read first line
                    if (line==null)
                        break;
                    String[] s = line.split(",");
                    Map<String,Integer> cityMap = flights.get(s[0]);
                    if (cityMap==null)
                        cityMap=new HashMap<String,Integer>();
                        flights.put(s[0],cityMap);
                    cityMap.put(s[1],Integer.parseInt(s[2]));
            } catch (IOException ex) {                    // catch I/O errors
                JOptionPane.showMessageDialog(this,"I/O error: " + ex.toString());  // show error message
    }

Answer 1

... i worked it out myself with the help of your code... works a treat
cheers
here is the answer:
    private void buttonOpenFileActionPerformed(java.awt.event.ActionEvent evt) {                                              
        // load the first line from a file into the firstlineBox textbox
        JFileChooser fileChooser = new JFileChooser();      // create a file chooser
        int returnVal = fileChooser.showOpenDialog(this); // show an open file dialogue
        if (returnVal == JFileChooser.APPROVE_OPTION) {   // was it successful (not cancelled)
            File file = fileChooser.getSelectedFile();    // if so, get selected file
            try {                                         // catch I/O errors
                FileReader fr = new FileReader(file);       // set up file reader
                MyFileReader readFile = new MyFileReader();
                readFile.readFile(fr);
            } catch (IOException ex) {                    // catch I/O errors
                  IOErrorMsg(ex);                 // show error message
    }