Re: Help with OutputStream.send() method. I want to know how much data this method already sent.
Dalton Barreto wrote:
So the class that sends the data has to know about the class that
implements the
progress bar, right?? This way the sender class will update the
progress directly, and
not the other way (the progress bar checking for total transfered
data), what is the
best way do implement this??
I tried to do something like this:
the class that sends the data increments a private variable, and the
class tha implements
the pBar keeps checking how much was sent so far. but this is bad,
because the only
way that I see to do this is: sleep some seconds e check again, then
get the totalBytes
transfered and do a += on the progerss status. But this is wrong,
because if the connection
is bad and the OS doesn't send any data in a short time slice the
progress bar would show
a inconsistent status (more data than actually transfered).
Is there any other way to do this 'comunication', between the sender
class and the pBar class, so the second show always a consistent status
value?
Thanks in advance!
Dalton Barreto;
PS: The class the send the data and the class that shows the progress
bar are two different
classes.
Look up JProgressBar
(http://java.sun.com/j2se/1.5.0/docs/api/javax/swing/JProgressBar.html)
if you are doing this in Swing.
If not using Swing, you probably still want to use the observer
pattern.
Psuedo-code:
class Uploader {
ProgressListener listener; // You can also make this a list/array of
listeners
int progress = 0;
public void doUpload() {
for (Chunk chunk: chunksToUpload) {
uploadChunk(chunk);
listener.progressChanged(progress);
}
}
}
Alternativly , you could make progress a JavaBean bound property, and
have the progress listener be a PropertyChangeListener, but thats more
work for now, and until you need it, I suggest holding off.
If you are doing this in Swing, make sure your event is fired off in
the EventDispatchThread
(http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html)
Hope this helps. Good luck.