jtable getvalueat does not recognize changed value

From:
vlenin66 <vlenin66@hotmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Tue, 27 May 2008 02:12:26 -0700 (PDT)
Message-ID:
<f3139a5a-7d1a-490b-aad7-faa246dde3c6@k30g2000hse.googlegroups.com>
Hi,

I have a table, add a row to it:
These are the results after having added a new row: (ccc 1,2,3,4 4000)
  Setting value at 2,1 to 1.2.3.4 (an instance of class
java.lang.String)
  New value of data:
    row 0: Cluster1 localhost 4000
    row 1: Cluster4 linux-suse103-2 4000
    row 2: ccc 1.2.3.4 4000
    row 3: 4000
    row 4: 4000
   ...
    row 29: 4000
  --------------------------
  Rows:30
   -----------------------------------------------------
However, the read out ( mtm.getValueAt(index, 1)) does not work:
  ----------------------------------------------------

   index:0 rechner:localhost
   localhost true
   index:1 rechner:linux-suse103-2
   linux-suse103-2 true
   index:2 rechner:
  -----------------------------------------

Can anybody help me, why does mtm.getValueAt not work?

Thanks in advance.

Here the complete program (sorry for the long list):
--------------------------------------------------------------------------
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.table.AbstractTableModel;

public class gridmonGuiConf1 extends JPanel {
    private JButton checkHosts;
    private JButton submit;
    private JTable clusterTable;
    private JList results;
    private DefaultListModel listModel;
    private JScrollPane listScrollPane;
    private JScrollPane scrollPane;

    private boolean DEBUG = true;

    public gridmonGuiConf1() {
        //construct preComponents
         String[] resultsItems = {"Item 1"};

        //construct components
        listModel = new DefaultListModel();
        listModel.addElement("linux-suse103-2");
        results = new JList (listModel);
        results.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        results.setSelectedIndex(0);
        results.setVisibleRowCount(7);
        listScrollPane = new JScrollPane(results);

        checkHosts = new JButton ("CheckHosts");
        submit = new JButton ("Submit");
        JTable clusterTable = new JTable(new MyTableModel());
        clusterTable.setPreferredScrollableViewportSize(new
Dimension(500,400));
        clusterTable.setFillsViewportHeight(true);
        clusterTable.setAutoCreateRowSorter(true);
        JScrollPane scrollPane = new JScrollPane(clusterTable);

        //adjust size and set layout
        setPreferredSize (new Dimension (409, 318));
        setLayout (null);

        //add components
        add (checkHosts);
        add (submit);
        add (scrollPane);
        add (listScrollPane);

        //set component bounds (only needed by Absolute Positioning)
        checkHosts.setBounds (130, 300, 110, 20);
        submit.setBounds (245, 300, 100, 20);
        scrollPane.setBounds (10, 5, 455, 290);
        listScrollPane.setBounds (10, 325, 455, 125);

       checkHosts.setMnemonic(KeyEvent.VK_C);
       submit.setMnemonic(KeyEvent.VK_S);

        CheckHostsListener checkHostsListener = new
CheckHostsListener();
        checkHosts.addActionListener(checkHostsListener);

    }
    class CheckHostsListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            Boolean result;
            //This method can be called only if
            //there's a valid selection
            //so go ahead and remove whatever's selected.
            int index = 0;
            NetworkHost nwh = new NetworkHost();
            MyTableModel mtm = new MyTableModel();
            int lsize = mtm.getRowCount();
            System.out.println("Rows:"+lsize);
            listModel.removeAllElements();
           while(index < lsize){
                 String rechner = mtm.getValueAt(index, 1).toString();
                 System.out.println("index:"+index+"
rechner:"+rechner);
                 if(rechner.length() > 0){
                  result = nwh.CheckHost(rechner);
                  System.out.println(rechner +" "+result);
                  if(result == false) {
                   listModel.addElement( rechner +" "+result);
                  }
                }
                 ++index;
            }

            System.out.println("CheckHosts");
        }
    }

    class MyTableModel extends AbstractTableModel {
        private String[] columnNames = {"Cluster Name",
                                        "Server name",
                                        "port"};
        private Object[][] data = {
            {"Cluster1",
             "localhost", new Integer(4000)},
            {"Cluster4",
             "linux-suse103-2", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
            {"",
             "", new Integer(4000)},
         };

        public int getColumnCount() {
            return columnNames.length;
        }

        public int getRowCount() {
            return data.length;
        }

        public String getColumnName(int col) {
            return columnNames[col];
        }

        public Object getValueAt(int row, int col) {
            return data[row][col];
        }

        /*
         * JTable uses this method to determine the default renderer/
         * editor for each cell. If we didn't implement this method,
         * then the last column would contain text ("true"/"false"),
         * rather than a check box.
         */
        public Class getColumnClass(int c) {
            return getValueAt(0, c).getClass();
        }

        public boolean isCellEditable(int row, int col) {
            //Note that the data/cell address is constant,
            //no matter where the cell appears onscreen.
            if (col < 0) {
                return false;
            } else {
                return true;
            }
        }

        public void setValueAt(Object value, int row, int col) {
            if (DEBUG) {
                System.out.println("Setting value at " + row + "," +
col
                                   + " to " + value
                                   + " (an instance of "
                                   + value.getClass() + ")");
            }

            data[row][col] = value;
            fireTableCellUpdated(row, col);

            if (DEBUG) {
                System.out.println("New value of data:");
                printDebugData();
            }
        }

        private void printDebugData() {
            int numRows = getRowCount();
            int numCols = getColumnCount();

            for (int i=0; i < numRows; i++) {
                System.out.print(" row " + i + ":");
                for (int j=0; j < numCols; j++) {
                    System.out.print(" " + data[i][j]);
                }
                System.out.println();
            }
            System.out.println("--------------------------");
        }
    }

    public static void main (String[] args) {
        JFrame frame = new JFrame ("gridmonGuiConf1");
        frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add (new gridmonGuiConf1());
        frame.pack();
        frame.setVisible (true);
    }
}

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