DWR

Usage:

either:
   function uploadFiles() {
        RemoteClass.uploadFiles(dwr.util.getValue("file1"), dwr.util.getValue("file2"), { fileProgress: true });
   }

or:
   function uploadFiles() {
    dwr.engine.setFileProgress(true);
        RemoteClass.uploadFiles(dwr.util.getValue("file1"), dwr.util.getValue("file2"));
   }

Changes Required:
1. client: Display the progress bar using logic similar to useLoadingImage() described here http://getahead.org/dwr/browser/util/useloadingmessage
2. server: Change org.directwebremoting.dwrp.ParseUtil to sends the status back to the browser using reverse ajax for each file being uploaded.
3. client: Use the status to update the progress bar.

Suggestied Solution:
1. Three new functions required in engine.js:
   showFileProgressBars(): hides file inputs and displays progress bars in their place, gives each progress bar an id
   updateFileProgressBar(id, percentage): updates a status bar with the upload percentage
   hideFileProgressBars(): display the file inputs in place of the progress bars

2. org.directwebremoting.dwrp.ParseUtil should set a progress listener on SERVLET_FILE_UPLOAD.