set automatically expiration date in a JTextField

How can I set automatically expiration date in a JTextField if i already know current date-dd/mm/yyyy ( from a JTextFiled) and frequency(monthly etc)?

Thank you!

[174 byte] By [denisaa] at [2007-11-27 10:48:43]
# 1

SimpleDateFormat? setText()? JFormattedTextField?

CeciNEstPasUnProgrammeura at 2007-7-28 22:29:00 > top of Java-index,Java Essentials,Java Programming...
# 2

This is the code

public void actionPerformed(ActionEvent ae){

String data=tf10.getText();

DateFormat df=DateFormat.getDateInstance(DateFormat.SHORT);

try{

df.parse(data);

}catch(ParseException nf){

JOptionPane.showMessageDialog(this,"Complet data");

return;

}

and after I press the button i want to display in next JtextField expiration date. I don`t know if it is good how I have created it

denisaa at 2007-7-28 22:29:00 > top of Java-index,Java Essentials,Java Programming...