DecimalFormat decimal places

Question

Currently, I have BigDecimal values with 3 decimal places shown in a JTable. When i get values as 2.500 or 1.000, I want to have 2.5 and 1.0 instead. That's why I tried this:

                    BigDecimal value;
                BigDecimal value3 = new BigDecimal((String)model.getValueAt(e.getLastRow(), 1)).setScale(3, BigDecimal.ROUND_HALF_UP);
                BigDecimal value2 = new BigDecimal((String)model.getValueAt(e.getLastRow(), 1)).setScale(2, BigDecimal.ROUND_HALF_UP);
                if(valor3.equals(value2))
                {
                    BigDecimal value1 = new BigDecimal((String)model.getValueAt(e.getLastRow(), 1)).setScale(1, BigDecimal.ROUND_HALF_UP);
                    if(value3.equals(value1))
                        value = valuer1;
                    else
                        value = value2;
                }
                else
                    value = value3;

But it doesn't work. It looks like '2.500'.equals('2.5') were false.

I also tried to give format to the JTable at its renderer:

 class paramRenderer extends DefaultTableCellRenderer
{
    private final DecimalFormat formatter = new DecimalFormat( "#.000" );

    public void setValue() {    
        formatter.setMinimumFractionDigits(1);
        formatter.setMaximumFractionDigits(3);
    }
}

But it makes no difference at all.

Any other idea?

EDIT: Finaly I found over the Internet a solution:

BigDecimal trim(BigDecimal n)
{
    try
    {
        while (true)
        {
            n = n.setScale(n.scale()-1);
        }
    }
    catch (ArithmeticException e)
    {
        // Not "real" error: No more trailing zeroes -> Just exit // setScale() tries to eliminate a non-zero digit -> Out of the loop // Remember exceptions are not recommended for exiting loops, but this seems to be the best way...
    }

    return n;
}

And works great! Thank you very much for the help anyway :)

http://stackoverflow.com/questions/6556651/jtable-cell-editor-number-format/6556681#6556681 — mKorbel, Jul 11 '11 at 11:17

score 0 · Answer 1 · answered Jul 11 '11 at 11:15

0

Try this format #.0## for the formatter

answered Jul 11 '11 at 11:15

denis.solonenko

11,645
2
28
23

It doesn't work. I'm updating the JTable values with TableModel.setValueAt(float value, int row, int column), while I'm extending the setValue method at the renderer... I know I'm doing wrong, but where shall I fix this? – Roman Rdgz Jul 11 '11 at 11:22

score 0 · Accepted Answer · answered Jul 11 '11 at 11:17

the first comparison is false, because you have different scales - value2 has 2 and value3 has 3. If you make them the same, it works
you don't need BigDecimal if you only want to display things. The decimal format should work, but you should also set the maximum fraction digits to 1

score 0 · Answer 3 · answered Jul 11 '11 at 11:22

0

Try to do like this,

DecimalFormat df = new DecimalFormat("#.#");
df.format(2.500);   // returns 2.5
df.format(1.000);   // returns 1.0

answered Jul 11 '11 at 11:22

Saurabh Gokhale

53,625
36
139
164

does not work for BigDecimal... and I want to have 3 decimal places when needed, not one always – Roman Rdgz Jul 11 '11 at 11:25

DecimalFormat decimal places

3 Answers3