Limit number of chars per line

Question

Hi ,
how to limit the number of chars per Line in a textArea or RTFEditableText?
I have to do the following:
Allow 25 Chars for first line,
any other line should have max. 28 chars.
First line should have a bold font.
Not an easy thing..
I tried to use a textarea fpr input and put the text into a datagrid in the textarea.change() event.
This works, but I lose a lot of the standard features of the textarea (hyphenation etc.)
The idea is to use only the textarea or a RTFEditor for applying the rules mentioned above.
Thanks
thorsten

Answer 1

extend PlainDocument class to restrict the number of characters per line.
Set this class as model to TextArea.
Below is a class which does this. May be its useful
import javax.swing.*;
import javax.swing.text.*;
import java.awt.*;
public class FixedNumericDocument extends PlainDocument {
private int maxLength = 9999;
private String max="";
public FixedNumericDocument(int maxLength) {
super();
this.maxLength = maxLength;
//this is where we'll control all input to our document.
//If the text that is being entered passes our criteria, then we'll just call
//super.insertString(...)
public void insertString(int offset, String str, AttributeSet attr)
throws BadLocationException {
if (getLength() + str.length() > maxLength) {
return;
else {
try {
//check if str is numeric only
int value = Integer.parseInt(str);
//if we get here then str contains only numbers
//chk if it is less than 65535 so that it can be inserted
super.insertString(offset, str, attr);
catch(NumberFormatException exp) {
return;
return;