Limiting entry in a JTextField to numeric value and "%" value

Question

Hi,
I want to allow the user to enter numeric value and % value
How can I limit the user to make such a entry in JTextField

Answer 1

Use the code given below to make your textfield accept only numeric values. You can modify itto include % values too.
textField.setDocument( new TextFieldVerifier() );     
class TextFieldVerifier extends PlainDocument {
public void insertString( int offset, String str, AttributeSet attSet ) throws BadLocationException {           
boolean valid = false;          
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 );
try {
/* check if the new string is a valid integer */
Integer.parseInt( newStr );               
valid = true;
} catch ( NumberFormatException ne ) {          
/* invalid, if not an integer */
valid = false;
Toolkit.getDefaultToolkit().beep();           
if ( valid ) {
super.insertString( offset, str, attSet );
}