Java Development Tools

good day,

does anyone know what the best way is to download a file to the client side using ADF? is this a trivial thing to do? i can find docs online on how to upload files using ADF but nothing for downloading files using ADF.

initially, my thought was to use the FacesContext ResponseStream; but quickly realized that facesContext.getResponseStream returns a null with in my backend bean. so, i decided to bypass ADF and use HttpServletResponse's ServletOutputStream and simply write to this object. this works fine but ran into another problem, this comletely bypasses the ADF framework. after downloading the file ADF does not know what state it is in (i.e. my pages do not get updated). nothing gets updated via ADF.

a second approach was to to kick off writing the Servlet OutputStream in a separate thread and have the backend bean return first. well... ran into another problem: java.lang.IllegalStateException: getOutputStream() has already been called!. obviously, i do not understand how the response mechanism works for servlets :-( it appears that per request the ouputstream can be only written to/flushed once.

so if anyone has a way to correctly download a file using ADF please share.

thank you