How to get the progress when copying a file using BufferedOutputStream & SwingWorker

Question

I am copying a file from my computer to an external device, such as an SD card, and I would like to get the progress during the file copying process. I am using SwingWorker so that I can have multiple files copying at the same time. I am not sure how to get the current progress and send it to the SwingWorker publish() method. Here is my code to copy the file:

FileInputStream finStream = new FileInputStream(sourceFile);
FileOutputStream foutStream = new FileOutputStream(destFile);

/*
 * Adapted from http://www.java2s.com/Code/Java/File-Input Output/UseBufferedInputStreamandBufferedOutputStreamtocopybytearray.html
 */
BufferedInputStream bufIS = new BufferedInputStream(finStream);     
BufferedOutputStream bufOS = new BufferedOutputStream(foutStream);

byte[] byteBuff = new byte[32 * 1024];
int len;
while ((len = bufIS.read(byteBuff)) > 0){
    bufOS.write(byteBuff, 0, len);
    publish(/*What do I put here?*/);
}

bufIS.close();
bufOS.close();

Answer 1

Swingworker has already a "progress feature", use it instead of publish/process

long size = file.length();

int count = 0;
int progress;
while ((len = bufIS.read(byteBuff)) > 0) {
  ...
  count += len;
  if (size > 0L) {
    progress = (int) ((count * 100) / size);
    setProgress(progress);
  }
}

Then you can use worker.getProgress() in EDT or a PropertyChangeListener with a progressBar or whatever

E.g:

public class MyWorker extends SwingWorker<Void, Void> implements PropertyChangeListener {

    public MyWorker() {
      addPropertyChangeListener(this);
    }

    ....
    /* Your code */
    ....

   @Override
   public void propertyChange(PropertyChangeEvent evt) {

      if ("progress".equals(evt.getPropertyName())) {
        myProgressBar.setValue((Integer) evt.getNewValue());
      }
   }

}

Or

MyWorker worker = new MyWorker();
worker.addPropertyChangeListener(new PropertyChangeListener() {

    @Override
    public void propertyChange(PropertyChangeEvent evt) {
        if ("progress".equals(evt.getPropertyName())) {
            myProgressBar.setValue((Integer) evt.getNewValue());
        }
    }
}

If you prefer publish/process then public class MyWorker extends SwingWorker<Void, Integer> and you will be able to call publish with an Integer

Answer 2

1. first find the size of the file. Use the length method in java.io.File
2. Use the 'len' variable to determine how many bytes have been copied in the current iteration of the loop.
3. Use that data to compute the percentage and use that.

NOTE: The data written may be to the buffer and will be flushed depending upon the size of buffer allocated (this should not hinder the calculation though).