Need some help. I want to have this FindPrimes program to be able to redo its sunction without having to restart the program. Here is the text of the program. Esentaially what I am asking for is a addition to this program that will erase the textbox and allow the user to enter a quantity and have the program display the prime numbers.

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

class FindPrimes extends JFrame implements Runnable, ActionListener {
Thread go;
JLabel howManyLabel = new JLabel("Quantity: ");
JTextField howMany = new JTextField("400", 10);
JButton display = new JButton("Display Primes");
JTextArea primes = new JTextArea(8, 40);

FindPrimes() {
super("Find Prime Numbers");
setSize(400, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container content = getContentPane();
BorderLayout bord = new BorderLayout();
content.setLayout(bord);
display.addActionListener(this);
JPanel topPanel = new JPanel();
topPanel.add(howManyLabel);
topPanel.add(howMany);
topPanel.add(display);
content.add(topPanel, BorderLayout.NORTH);
primes.setLineWrap(true);
JScrollPane textPane = new JScrollPane(primes);
content.add(textPane, BorderLayout.CENTER);
setVisible(true);
}

public void actionPerformed(ActionEvent evt) {
display.setEnabled(false);
if (go == null) {
go = new Thread(this);
go.start();
}
}

public void run() {
int quantity = Integer.parseInt(howMany.getText());
int numPrimes = 0;
// candidate: the number that might be prime
int candidate = 2;
primes.append("First " + quantity + " primes:");
while (numPrimes < quantity) {
if (isPrime(candidate)) {
primes.append(candidate + " ");
numPrimes++;

}
candidate++;
}
}

public static boolean isPrime(int checkNumber) {
double root = Math.sqrt(checkNumber);
for (int i = 2; i<= root; i++) {
if(checkNumber % i == 0)
return false;

}
return true;
}

public static void main(String[] arguments) {
FindPrimes fp = new FindPrimes();
}
}

Thanks for any help you can give