Apache commons file upload and percentage progress in Google Apps

I am trying to use ProgressListener update call to obtain percentage completion of each file. Number of files are dynamically chosen 开发者_JAVA技巧and uploaded.

public class ProgressListenerImpl implements ProgressListener 

Will I be able to use the "item" parameter in the update call?

update(long bytesRead, long contentLength, int item)

And associate them to each iframe dynamically created in UI? Is there alternative suggestions that are easier or simpler in nature?

The application has to be in Java hosted on Google App Engine. I am not saving files to any filesystem but using the stream to redirect data to Google sites.

Your code isn't called until the entire request has been received - so no, you can't monitor upload progress from the server end.