Synchronize JProgressBar and OutputStream
Hello;
I read a file via a FileInputStream and I write byte[] in a DataOutputStream over the network (via HTTPURLconnection and not a Java socket). I implements a JProgressBar to know the size is send, but it seems that the progressbar read the size is read and not the size is send. My question is: is there a way to know exactelly the byte size really send over a HttpUrlConnection at a time ?
thanks a lot
Here's some psuedocode on how you should be doing it..
regards,
Owen
progressbar.setMaximum ( 0 );
progressbar.setMaximum ( 100 );
long fileSize = file.getSize();
long sentByteCount = 0;
while ( sent != fileSize )
{
sentByteCount + = outstream.write ( whatever );
// working in percentages
progressbar.setValue ( (int) ( (sent / fileSize) * 100.0 );
}
progressbar.setValue ( 100 );
You might want to create a thread that asks the outputstream for its progress periodically instead. If you write to a file, for instance, and update the progressbar every time write read a byte, you might end up with about a million calls to repaint, which isn't good.
So create an outputstream:
public class ProgressOutputStream extends OutputStream
{
OutputStream source;
int bytesWritten;
public ProgressOutputStream(OutputStream source)
{
this.source = source;
}
public void write(int n) throws IOException
{
bytesWritten += 1;
source.write(n);
}
public int getBytesWritten()
{
return bytesWritten;
}
}
And this:
public class StreamProgressBar extends JProgressBar
{
OutputStream stream;
public StreamProgressBar(OutputStream out, int size)
{
stream = new ProgressOutputStream(out);
setMinimumValue(0);
setMaximumValue(size);
}
private class ProgressMonitorThread extends Thread
{
public void run()
{
try{Thread.sleep(100);}catch(Exception e){e.printStackTrace();}
setValue(out.getBytesWritten());
}
}
}
This is just an example, and can be made much nicer...
Regards,
Nille
