Exact length of a JTextField

Question

Hi,
I have a program where I read integer value from the database & create a JTextField on the GUI side. Number of characters user should enters in the JTextField should be equal to the value I have got from the database & only JTextField with columns 10 should be displayed
e.g If I get integer value 10 , I create a JTextField & call setColumns(10);
here is my program:
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
public class test extends javax.swing.JFrame
     public test(String title) throws Exception
          super(title);
          this.setLayout(new java.awt.FlowLayout());
          javax.swing.JTextField tf = new javax.swing.JTextField();
          tf.setDocument(new LimitDocument(2));
          tf.setMargin(new Insets(0,0,0,0));
          tf.setColumns(2);
          this.getContentPane().add(tf);
     public static void main(String[] args) throws Exception
          test t = new test("Test");
          t.setSize(new java.awt.Dimension(500,500));
          t.setVisible(true);
//Inner Class
class LimitDocument extends PlainDocument {
private int limit;
public LimitDocument(int limit) {
super();
setLimit(limit); // store the limit
public final int getLimit(){
return limit;
public void insertString(int offset, String s, AttributeSet attributeSet) throws BadLocationException {
if(offset < limit){ // if we haven't reached the limit, insert the string
super.insertString(offset,s,attributeSet);
} // otherwise, just lose the string
public final void setLimit(int newValue) {
this.limit = newValue;
after running this propgram , I found that even if user is able to enter only the number of characters specified , but still JTextField leaves some SPACE after number of characters entered
In above example , I have Limit number of characters to be entered to 2
but after entering 2 chars , it showd some SPACE in the end, I dont want to show this SPACE to the user.
Pleae guide me
Thanks in advance
NJP

Answer 1

In above example , I have Limit number of characters to be entered to 2
but after entering 2 chars , it showd some SPACE in the end, I dont want to show this SPACE to the user.
Type "mm" into the field and you'll see that the string fills the box. Naturally, with a proportional font, "ii" etc won't.
By the way, the logic in your LimitDocument is flawed: as an illustraction, paste a string in there - or type two characters, move the cursor left and carry on typing.