Save/Load into Jtable

Question

How can I load data and save data from Jtable in a comma delimited format?
And how can I execute a calculation by writing r1c3+r1c2 in a Jtextfield. R1 means row1 c3 means column3. What method or class can I use to locate the data on the JTable and do the calculation.
public class SpreadSheetEditor extends JFrame  implements ActionListener
     JFileChooser chooser = new JFileChooser();
      * This constructs the GUI.  It is not a public method to be called by other
      * classes.
     protected SpreadSheetEditor()
          // Set title bar text and close box functionality on the JFrame
          super("SpreadSheetEditor");
          // Add content pane to JFrame and set to Border Layout
          Container contentPane = this.getContentPane();
          contentPane.setLayout(new BorderLayout(20,20));
          // Add JScrollPane to center of ContentPane and set scroll bar policy
          JScrollPane myScrollPane = new JScrollPane();
          myScrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
          myScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
          contentPane.add(myScrollPane, BorderLayout.CENTER);
          // Add JTable to ScrollPane
          JTable myTable = new JTable(20,10);
          TableColumn column = new TableColumn();
          myScrollPane.setViewportView(myTable);
          myTable.setRowHeight(20);
          column.setPreferredWidth(50);
          // Add JPanel to bottom (south) of content pane for buttons
          JPanel myPanel = new JPanel();
          myPanel.setLayout(new FlowLayout(FlowLayout.CENTER));
          contentPane.add(myPanel, BorderLayout.SOUTH);
          // Add TextField
          JTextField textField = new JTextField(20);
          contentPane.add(textField, BorderLayout.SOUTH);
          // Create and add load and save and execute buttons to JPanel
          JButton loadButton = new JButton("Load");
          JButton saveButton = new JButton("Save");
          JButton executeButton = new JButton("Execute");
          myPanel.add(executeButton);
          myPanel.add(loadButton);
          myPanel.add(saveButton);
          // Crerate a JMenu
          JMenu menu = new JMenu("File");
          JMenuItem m;
          m= new JMenuItem("Clear SpreadSheet");
          m.addActionListener(this);
          menu.add(m);
          m= new JMenuItem("Exit Editor");
           m.addActionListener(this);
          menu.add(m);
          JMenuBar mBar = new JMenuBar();
          mBar.add(menu);
          setJMenuBar(mBar);
          // Add action listeners to buttons
          loadButton.addActionListener(this);
          saveButton.addActionListener(this);
           executeButton.addActionListener(this);
          // Set frame size and make visible
          super.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          super.setSize(500,500);
          super.setVisible(true);
      * This method calls either loadFile or saveFile in reponse
      * to the buttons being pushed.
      * @param e the event from the button push
     public void actionPerformed(ActionEvent e)
          if (e.getActionCommand().equals("Load"))
               loadFile();
          else if (e.getActionCommand().equals("Save"))
               saveFile();
          else if(e.getActionCommand().equals("Exit Editor"))
               System.exit(1);
     //     else if(e.getActionCommand().equals("Clear SpreadSheet"))
     //          theText.setText("");
      * This pops the file chooser and then calls the loadFile(File) method.
     protected void loadFile()
          int returnVal = chooser.showOpenDialog(this);
          if(returnVal == JFileChooser.APPROVE_OPTION)
               loadFile(chooser.getSelectedFile());
      * This loads the file and displays it in the textArea.
      * @param fileToLoad the file to load in to the text area
     protected void loadFile(File fileToLoad)
          try
               FileReader freader = new FileReader(fileToLoad);
               BufferedReader breader = new BufferedReader(freader);
              String line;
              while ((line = breader.readLine()) != null)
              //     myJTable.append(line + "\n");
              breader.close();
          catch (IOException ioe)
               ioe.printStackTrace();
      * This takes what is in the JTable and saves it to a file.
      * Pops a JChooser to determine the file name.
     protected void saveFile()
          int returnVal = chooser.showSaveDialog(this);
          if(returnVal == JFileChooser.APPROVE_OPTION)
               try
                    FileWriter fwriter = new FileWriter(chooser.getSelectedFile());
                    BufferedWriter bwriter = new BufferedWriter(fwriter);
               //     bwriter.write(myJTable.getText());
                    bwriter.close();
               catch (IOException ioe)
                    ioe.printStackTrace();
      * The main method creates an instance of SpreadSheetEditor.
     public static void main(String[] args)
          SpreadSheetEditor myEditor = new SpreadSheetEditor();
}

Answer 1

First a suggestion, break up your GUI into a couple of classes. It would be perferable if in your constructor you had something more like
super("SpreadSheet Editor");
setJMenuBar(new myOwnMenuBar());
getContentPane.add(new mySpreadsheetPanel());and then the SpreadsheetPanel would be broken up into the JTable, and maybe a panel with some buttons on it if you need them. Just a suggestion, it tends to make the code much easier to debugg and change/add functionality to later.
As for loading a file, you should know the format of the data. I would store it something like
rowcol, data, rowcol, data, rowcol, data
then just read it in and fill it into the table where needed.
You should create your own TableModel which should be a subclass of AbstractTableModel. This will make your life easier. The TabelModel is where the JTable gets/stores all its data, and it is what is used to update the JTable.
As for the calculations here is a class I wrote for doing a similar project. There are a couple of classes used but they are mostly small classes and if you need more explenation on them just let me know.
import java.util.StringTokenizer;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
  *@author
  *@version 1.0 3/5/03
  *the ExpressionTree class is used to evaluate and hold a mathmatical expression
public class ExpressionTree{
     SimpleStack numberstack, opstack, cellrefs;
     String originalexpression;
     Token root;
     Graph graph;
       *creates an Expression tree
       *@param expression the expression to be evaluated
       *@param graph a reference to the Graph where cells are stored
       *@throws MalformedCellException thrown if the expression is invalid
     ExpressionTree(String expression, Graph graph)throws MalformedCellException{
          originalexpression      = expression;
          this.graph              = graph;
          StringTokenizer extoken = new StringTokenizer(expression, OperatorToken.OPERATORS, true);
          String[] tokens         = new String[extoken.countTokens()];
          for(int i=0;i<tokens.length;i++){
               tokens=extoken.nextToken();
          buildTree(tokens);
     //creates the tree from the array of tokens each token is a portion of the expression
     private void buildTree(String[] tokens)throws MalformedCellException{
          boolean checkunaryminus = true;
          boolean unaryminus = false;
          numberstack = new SimpleStack(13);
          opstack = new SimpleStack(13);
          cellrefs = new SimpleStack(13);
          for(int i=0;i<tokens.length;i++){
               if(LiteralToken.isLiteral(tokens[i])){
                    if(unaryminus){
                         numberstack.push(new LiteralToken(-1*Double.parseDouble(tokens[i])));
                         opstack.pop();
                         unaryminus = false;
                    }else{
                         numberstack.push(new LiteralToken(Double.parseDouble(tokens[i])));
                    checkunaryminus = false;
               }else if(CellToken.isCell(tokens[i])){
                    Cell tempcell = getCell(tokens[i]);
                    cellrefs.push(tempcell);
                    Token temp = new CellToken(tempcell);
                    if(unaryminus){
                         temp = buildSubTree(new LiteralToken(0), (OperatorToken)opstack.pop(), temp);
                         unaryminus = false;
                    numberstack.push(temp);
                    checkunaryminus = false;
               }else if(OperatorToken.isOperator(tokens[i])){
                    if(unaryminus) throw new MalformedCellException("illegal expression operator after minus");
                    char op = tokens[i].charAt(0);
                    if(checkunaryminus){
                         if(op=='-'){
                              opstack.push(new OperatorToken(op));
                              checkunaryminus = false;
                              unaryminus = true;
                         }else{
                              opstack.push(new OperatorToken(op));
                    }else{
                         if(op=='('){
                              opstack.push(new OperatorToken(op));
                         }else if(op==')'){
                              OperatorToken temp = (OperatorToken)opstack.pop();
                              while(temp.instancePriority() != OperatorToken.getPriority('(')){
                                   if(numberstack.numObjects()<2){
                                        throw new MalformedCellException("Incefficient Numbers");
                                   Token r = (Token)numberstack.pop();
                                   Token l = (Token)numberstack.pop();
                                   numberstack.push(buildSubTree(l, temp, r));
                                   temp = (OperatorToken)opstack.pop();
                         }else{
                              if(!opstack.isEmpty()){
                                   OperatorToken ot = (OperatorToken)opstack.peek();
                                   if(OperatorToken.getPriority(op)<ot.instancePriority()){
                                        if(numberstack.numObjects()<2){
                                             throw new MalformedCellException("Incefficient Numbers");
                                        Token r = (Token)numberstack.pop();
                                        Token l = (Token)numberstack.pop();
                                        numberstack.push(buildSubTree(l, (OperatorToken)opstack.pop(), r));
                              opstack.push(new OperatorToken(op));
                         checkunaryminus = true;
               }else{
                    throw new MalformedCellException("illegal expression Failed all tests");
          while(!opstack.isEmpty()){
               if(numberstack.numObjects()<2){
                    throw new MalformedCellException("Incefficient Numbers");
               Token r = (Token)numberstack.pop();
               Token l = (Token)numberstack.pop();
               numberstack.push(buildSubTree(l, (OperatorToken)opstack.pop(), r));
          root = (Token)numberstack.peek();
     *gets the value of this expression
     *@return String returns the value of this expression in a String
     public String getValue(){
          double temp = root.getValue();
          return String.valueOf(temp);
     *gets the original expression that was parsed
     *@return String the original expression
     public String getEquation(){
          return originalexpression;
     *get the cells that are reference in this expression
     *@return Cell[] array of cells this expression holds
     public Cell[] getReferences(){
          Cell[] returncells = new Cell[cellrefs.numObjects()];
          int index = 0;
          while(!cellrefs.isEmpty()){
               returncells[index++]=(Cell)cellrefs.pop();
          return returncells;
     //builds one three node subtree
     private Token buildSubTree(Token l, OperatorToken ot, Token r){
          ot.setLeftChild(l);
          ot.setRightChild(r);
          return ot;
     //uses buildSubTree to create a tree until more of the expression needs to be parsed
     private Token buildSubTrees(char op)throws MalformedCellException{
          if(op==')'){
               OperatorToken ot = (OperatorToken)opstack.peek();
               while(ot.instancePriority()!=0){
                    if(numberstack.numObjects()<2){
                         throw new MalformedCellException("Incefficient Numbers");
                    Token r = (Token)numberstack.pop();
                    Token l = (Token)numberstack.pop();
                    numberstack.push(buildSubTree(l, (OperatorToken)opstack.pop(), r));
          }else{
               OperatorToken ot = (OperatorToken)opstack.peek();
               while(OperatorToken.getPriority(op)<ot.instancePriority()){
                    if(numberstack.numObjects()<2){
                         throw new MalformedCellException("Incefficient Numbers");
                    Token r = (Token)numberstack.pop();
                    Token l = (Token)numberstack.pop();
                    numberstack.push(buildSubTree(l, (OperatorToken)opstack.pop(), r));
          return (Token)numberstack.peek();
     //gets or creates cell that is referenced in expression
     private Cell getCell(String cellname)throws MalformedCellException{
          int row = 0;
          int col = 0;
          Pattern colpatt = Pattern.compile("[a-zA-Z]+");
          Pattern rowpatt = Pattern.compile("\\d+");
          Matcher m = colpatt.matcher(cellname);
          m.find();
          String columnstring = m.group().toUpperCase();
          m = rowpatt.matcher(cellname);
          m.find();
          String rowstring = m.group();
          row = Integer.parseInt(rowstring);
          row--;
          char[] colchar = columnstring.toCharArray();
          for(int j=colchar.length-1;j>=0;j--){
               col+=colchar[j]-'A'*Math.pow(26, j);
          if(row<0||col<0){
               throw new MalformedCellException("illegal expression");
          Vertex v = graph.doesCellExist(col, row);
          if(v!=null){
               return v.getCell();
          return new Cell(col, row, "0", graph);