How to set the maximum length in a JTextField component.

Question

Hi This is a basic doubt. How can i set the maximum lenght in a JTextField.. I tried the setColumns() method. It doesnt do anything.. Pls Help.
Thanks
Rajeev

Answer 1

Here's an example using PlainDocument.
textField.setDocuemnt( new TextFieldVerifier() );
class TextFieldVerifier extends PlainDocument {
int requiredLength = 10; // whatever length you want
public void insertString( int offset, String str, AttributeSet attSet ) throws BadLocationException {           
boolean valid = true;          
if (str == null) {
return;
String old = getText( 0, getLength() );
/* insert the new string at the given offset, into the old string */     
String newStr = old.substring( 0, offset ) + str + old.substring( offset );
if (newStr.length() > requiredLength)
valid = false;
Toolkit.getDefaultToolkit().beep();
if ( valid )
super.insertString( offset, str, attSet );
}