Show progress with I/O

Question

I have the following piece of code within an event which does a lot of reading and writing from and into different files. The process takes about 10 seconds.
ProgBar p = new ProgBar(jProgressBar1);
void okbutton_actionPerformed(ActionEvent e)
    temp = usernametextfield.getText().trim(); //temp is a string
    if (temp.length()>0)
      p.start();
      load();
      saveData();
      savewelcomeframe();
      savedeleteframe();
      savemainframe();
      retrievewelcomeframe();
      this.dispose();
    else JOptionPane.showMessageDialog(jOptionPane1, "Invalid Entries. Try again.","Error Message", JOptionPane.ERROR_MESSAGE);
  }On the frame where the okbutton is I want to use a JProgressBar in an Indeterminate mode. I wrote the following piece of code that returns a JProgressBar.
import java.awt.*;
import javax.swing.*;
public class ProgBar extends Thread {
  JProgressBar progbar1 = new JProgressBar();
  public ProgBar(JProgressBar prog) {
    progbar1 = prog;
  public void run(){
      progbar1.setIndeterminate(true);
      progbar1.setString("Loading...");
} It doesn't work. If I remove this.dispose() from the first piece of code, the progressbar works but only after all the reading and writing is done. In effect it looks like that my code works but not as independent threads.
I have read in the tutorial that I/O blocks progress bars, is that true in this case. and if it is? is there a way around it.
I don't want to use ProgressMonitorInputStream in a pop up window. Can you help?

Answer 1

Here's what I did:
1. I set up my I/O stuff working in a low priority thread. It looked something like:
int totallength = ...
int have = 0;
Inputstream in = ...
byte[] buf = new byte[4000];
while (have!=totallength) {
  int b = in.read(buf);
  if (b==-1) break; //some sort of error
  have+=b;
  ProgressBar.setValue(have/totallength);
}