JTable, reloading the table...

[Chris Stewart]

I want to reload the table at certain times in my application. I didn't find a reload method, so I tried doing this but it didn't work. Any ideas?

studentList = new JTable(getAllStudents(students), columnData);

- getAllStudents returns a 2D object array with all of my info.
- columnData is a 1D object array with the column names.

[Chris Stewart]

Update...
I'm not sure how to update the table, so I'm just using the setValueAt methods from the TableModel object. Problem is my event code continues to run in a loop because I'm changing the table inside of my tableChanged event. Does anyone know how I can get this to work like I want to?

public void tableChanged(TableModelEvent event)
  {
    Student s;
    int row = event.getFirstRow();
    int col = event.getColumn();
    String colName = model.getColumnName(col);
    Object data = model.getValueAt(row, col);
    System.out.println("Row: " + row);
    /*System.out.println("Col: " + col);
    System.out.println("New Data: " + data);
    System.out.println("That ID: " + model.getValueAt(row, 0) + "\n");*/
    s = students[Integer.parseInt((String)model.getValueAt(row, 0))];
    s.setFName((String)model.getValueAt(row, 1));
    s.setLName((String)model.getValueAt(row, 2));
    s.setSSN((String)model.getValueAt(row, 3));
    JOptionPane.showMessageDialog(null,
      "Student '" + model.getValueAt(row, 1) + " " + model.getValueAt(row, 2) + "' has been updated!",
      "Student updated!", JOptionPane.INFORMATION_MESSAGE);
    model.setValueAt(s.getFName(), row, 1);
    model.setValueAt(s.getLName(), row, 2);
    model.setValueAt(s.getSSN(), row, 3);
    //studentList = new JTable(getAllStudents(students), columnData);
    //studentList.repaint();
    //studentList.revalidate();
    /*for(int i = 1; i < students.length; i++)
    {
      Student n;
      n = students[i];
      System.out.println(n.getID() + " " + n.getFName() + " " + n.getLName() + " " + n.getSSN());
    }*/
   // updateStudentComboBox.u.updateUI(); // = new JComboBox(getAllNames(students));
    //deleteStudentComboBox = new JComboBox(getAllNames(students));
  }

[Abhik Sarkar]

Hi Chris,
If your table's data is going to be dynamic, I would stronly suggest that you write your own TableModel... it will give you a lot more control and I can assure you that it will be worth the additional effort.
However, if you must use the array, this might work...
1. Don't put anything in the event handling code.
2. Change the values directly in the array.
Then,

DefaultTableModel model = (DefaultTableModel) table.getModel();
model.fireTableDataChanged();

You should see the updated values in the table.
Hope this helps. I will try and give a working example when I have the time.
Regards,
Abhik.

[Chris Stewart]

I'm getting a ClassCastException on this line of code:

DefaultTableModel model = (DefaultTableModel) table.getModel();

[Garandi Garandi]

If you have extended "AbstractTableModel", then cast to sub-class of AbstractTableModel.

  
class MyModel extends AbstractTableModel{
}
.
.
.
MyModel model = (MyModel) table.getModel();
model.fireTableDataChanged();

This should do it.
Thank you
Garandi
Now in your code do

[Chris Stewart]

I can't extend anything else because I'm already extending JFrame. Would making another class work?
[ June 20, 2003: Message edited by: Chris Stewart ]

[Chris Stewart]

I tried creating a second class called myModel and extending AbstractTableModel, but on this line:
MyModel model = (MyModel) table.getModel();
I'm getting a ClassCastException.

[Gregg Bolinger]

Originally posted by Chris Stewart:
I'm getting a ClassCastException on this line of code:

DefaultTableModel model = (DefaultTableModel) table.getModel();

Why are you casting? I don't think you need to.

[Chris Stewart]

Ok, I got it working. Here is the myModel class:

package vcu.info350.homework2;
import javax.swing.table.AbstractTableModel;
/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: </p>
 * @author unascribed
 * @version 1.0
 */
public class myModel extends AbstractTableModel {
    private String[] columnData = new String[] {"ID", "First Name", "Last Name", "SSN"};
    private Object[][] data = null;
    public myModel(Student[] students)
    {
      data = new Object[50][4];
      Student s = null;
      int j = 0;
      // Add parts
      for(int i = 1; i < Student.getStudentCount(); i++)
      {
        s = students[i];
        try
        {
          data[j][0] = String.valueOf(s.getID());
          data[j][1] = s.getFName();
          data[j][2] = s.getLName();
          data[j++][3] = s.getSSN();
        }
        catch(NullPointerException ex)
        {
          //data[j++][0] = "Deleted";
        }
      }
    }
    public int getColumnCount() {
        return columnData.length;
    }
    public int getRowCount() {
        return data.length;
    }
    public String getColumnName(int col) {
        return columnData[col];
    }
    public Object getValueAt(int row, int col) {
        return data[row][col];
    }
    public Class getColumnClass(int c) {
        return getValueAt(0, c).getClass();
    }
    /*
     * Don't need to implement this method unless your table's
     * editable.
     */
    public boolean isCellEditable(int row, int col)
    {
        //Note that the data/cell address is constant,
        //no matter where the cell appears onscreen.
        if (col < 2) {
            return false;
        } else {
            return true;
        }
    }
    /*
     * Don't need to implement this method unless your table's
     * data can change.
     */
    public void setValueAt(Object value, int row, int col)
    {
        //...//debugging code not shown...
        //...//ugly special handling of Integers not shown...
        data[row][col] = value;
        fireTableCellUpdated(row, col);
        //...//debugging code not shown...
    }
}

Then in my Layout class, I use this to reload it:

model = new myModel(students);
studentList.setModel(model);
this.repaint();