First contribution?

Technically I did not check-in any changes to SVN, but I did suggest a fix for World Wind on the forums.

I have been spending a good while looking into the "download code" issue. I have taken a step back and this past weekend I dove into the code using my new development machine.

By tweaking a couple of lines of code I managed to unlock behavior already built in to the download classes that would prevent multiple failed downloads from repeating for a particular layer (after 5 failures, stop downloads for a timeout period of 2 minutes). This was slightly different from the expressed requirement to flag specific tiles for not being found and not retrying those.

So on April 5, 2009, I went back to the World Wind forums and posted my update including the changes to the two class files to make the existing functionality work correctly. I even got some replies by a few active members that they would try it out. I asked for clarification as well if I should go back and make the anti-hammer logic work for tiles specifically rather than whole layers which is what I initially wanted to do.

It was such a successful feeling on Sunday to get this working the way I wanted. My wife and I spent all day working on our various projects, me on World Wind, her on her doctoral dissertation. It took about 5-6 hours of steady work, debugging and reading log files to really wrap my head around how these classes were truly interacting. Making a simple change (which I understood) and having it work was very rewarding, it gives me confidence to continue with some more changes.

Things to check:

* One recommendation was to display a message in the UI that the connection to the server is on hold for the 2 minute timeout period. I did in fact see something like that at one point in my testing but it quickly went away, may have been unrelated to my code changes
* Pressing 'F5' will clear the cache for a specific area and force a retry of the download of the visible tiles. Suggestion was that this should reset any timeout or counters of failures if the user doesn't want to wait (I suppose would be the case if they scrolled back over some location that they were more confident had tiles to download from the server)
* Need validation on whether current anti-hammer logic is ok, or we need per-tile anti-hammer logic