JTable Cell data validation/blank cell problem

[Yash Sharma]

I am fairly new to Swings. I have a JTable that has to do some validations before its data is saved:
(1) Each row of the Table allows values within a set range ex:0.5 to 100
(2) The cell may allow blank (later replaced before save with the lower range value)

All cell data will be Float data. My questions:

(a) Right now I am iterating through JTable cells and checking each row-wise cell to see if they are within range. What is the correct way to do such validations?
(b) JTable by default is not allowing me to leave the cell blank (the focus remains on the cell if I try to leave it blank). How can I allow blank cell entries?
(c) If user enters an invalid data (say a String) in the cell that expects Float value, the text stays in the cell even though I clear the TableModel and repopulate the data. Any idea how to get over this?
[ October 07, 2004: Message edited by: Yash Sharma ]

[Yash Sharma]

Ranchers, I need a helping hand on this.

[Craig Wood]

import java.awt.*;
import java.util.Random;
import javax.swing.*;
import javax.swing.table.*;
public class FloatTest
{
public FloatTest()
{
int rows = 32;
int cols = 4;
String[] headers = { "columm 1", "column 2", "column 3", "column 4" };
FloatModel model = new FloatModel();
Float[][] data = model.getData(rows, cols);
model.setDataVector(data, headers);
JTable table = new JTable(model);
TableColumnModel columnModel = table.getColumnModel();
for(int j = 0; j < cols; j++)
{
TableColumn col = columnModel.getColumn(j);
col.setCellEditor(new FloatEditor());
}
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new JScrollPane(table));
f.setSize(500,400);
f.setLocation(200,200);
f.setVisible(true);
}
public static void main(String[] args)
{
new FloatTest();
}
}
class FloatEditor extends AbstractCellEditor implements TableCellEditor
{
JTextField textField;
public FloatEditor()
{
textField = new JTextField();
}
public Component getTableCellEditorComponent(JTable table,
Object value,
boolean isSelected,
int row, int col)
{
textField.setText(String.valueOf(value));
return textField;
}
public Object getCellEditorValue()
{
String s = textField.getText();
if(s.equals(""))
s = "0.5";
try
{
float f = Float.parseFloat(s);
}
catch(NumberFormatException nfe)
{
System.out.println("bad entry: " + nfe.getMessage());
return Float.valueOf("0.5");
}
return Float.valueOf(s);
}
public boolean stopCellEditing()
{
float f = ((Float)getCellEditorValue()).floatValue();
if(f < 0.5f || f > 100.0f)
{
fireEditingCanceled();
return false;
}
return super.stopCellEditing();
}
}
class FloatModel extends DefaultTableModel
{
Random seed;
public FloatModel()
{
seed = new Random();
}
public Class getColumnClass(int col)
{
int row = 0;
Object o = getValueAt(row, col);
if(o == null)
return Object.class;
else
return o.getClass();
}
public Float[][] getData(int rows, int cols)
{
float floor = 0.50f;
float ceil = 100.0f - floor;
Float[][] f = new Float[rows][cols];
for(int row = 0; row < rows; row++)
for(int col = 0; col < cols; col++)
f[row][col] = new Float(floor + seed.nextFloat() * (ceil + 1));
return f;
}
}

[Yash Sharma]

Thanks for the code. I think that also reflects the problem I am facing namely: I am not able to leave the cell blank (NumberFormatException : Empty String). I must have some valid float value in any case. How to avoid this?

[luo ware]

Hey ,try as following:
check the object value returned by getCellEditorValue() within fuction
stopCellEditing().
Object obj=getCellEditorValue();
if(obj.toString.length()<1){super.stopEditing;return ture;}