Solved

Sending an HTTP response after some time of processing

Posted on 2006-11-20
2
178 Views
Last Modified: 2010-04-01
I have 3 tier application that relies on a Servlet to contact a third-party server, exchange informations, and finally printing a JSP page with the data obtained by this transaction.

The fact is, this process takes some time and the application must wait for a thread called "ConnectionReader" to receive the message with the informations from the remote server.

In order to retain the chance to write on the client's browser, I saved the PrintWriter which I obtain from the HttpServletResponse object inside a Hashtable and I call him back when I need to print the result.

In short, is something like this:


- I receive the Http Request, and the DoGet() method is invoked;
- from the HttpServletResponse object I obtain the PrintWriter, which I put inside a Hashtable with a unique ID;
- after some time, the Reader thread reads a message from my remote connection to the server;
- I then proceed to retrieve the PrintWriter I saved before and print the resulting informations on it.


...but this doesn't work, and my page is still blank. What am I doing wrong?
Consider that if I write on this PrintWriter immediately after obtaining it, it works and I can see on the browser the output of what I write.

Thanks in advance for the help.
0
Comment
Question by:Emanuele_Ciriachi
2 Comments
 
LVL 9

Expert Comment

by:owenli27
ID: 17980508
What Exception you got, java.lang.IllegalStateException: xxxx ?
Your response cannot be commited becasue of connection lost after a certain time or printWriter may auto flush and commited response already.
0
 
LVL 12

Accepted Solution

by:
enachemc earned 500 total points
ID: 17985940
you should consider using a worker thread launched from the doGet. Wait for this thread to finish or some time to pass (you can use Object.wait(long time)). If the timeout occurs, display a message, if the processing has completed, display whatever you want. You could use the wait in a loop and provide some kind of progress bar to the user.

Do not try to keep the writer after the doGet has finished.
0

Featured Post

ScreenConnect 6.0 Free Trial

At ScreenConnect, partner feedback doesn't fall on deaf ears. We collected partner suggestions off of their virtual wish list and transformed them into one game-changing release: ScreenConnect 6.0. Explore all of the extras and enhancements for yourself!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Adding Computers to AD groups through an SCCM Task Sequence
February 24, 2017 — On February 23, Travis Ormandy, a vulnerability researcher at Google, reported on Twitter (https://twitter.com/taviso/status/834900838837411840) that massive stores of data have been leaked by CloudFlare, a company that provide…
This Micro Tutorial demonstrates using Microsoft Excel pivot tables, how to reverse engineer competitors' marketing strategies through backlinks.
Established in 1997, Technology Architects has become one of the most reputable technology solutions companies in the country. TA have been providing businesses with cost effective state-of-the-art solutions and unparalleled service that is designed…

810 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question