What was the hardest to program this year in Java?

[synth3tk]

Originally Posted by michael714

Not sure why writing data to the DriverStationLCD was so time consuming, but we experienced that and noticed that others have made posts about it as well.

I waited for CD on that one. I remember figuring out how to set an autonomous mode during disable (which is a really cool trick [though I never got autonomous working]) right before researching the DriverStationLCD deal.

Other than that, 964's code was relatively simple, so we didn't go through the hassle of writing our own classes or anything exciting.

[jhersh]

Originally Posted by FRC4ME

Oh, and I forgot to mention: finding and fixing bugs in WPI's code.

So far we're overriding three of WPI's classes with our own versions: PWM, because someone forgot to cast two integers to doubles before dividing them; Encoder, because someone divided by 0.25 when they should have divided by four; and DriverStation, because the scaling on the joystick axes is wrong (it goes from -1.0 to 0.9 rather than -1.0 to 1.0 due to the use of two's complement).

Not that I'm complaining; when volunteers write 20,000 lines of code there are bound to be a few errors. In fact, I'm glad WPILib isn't perfect, because then my programming team would have nothing to do after week one.

Have you reported all the bugs you found so that the library can be improved for everyone? Even better would be patches that implement the fixes.

Visit http://firstforge.wpi.edu/sf/tracker...wpilib/tracker to report bugs!

Thanks,
-Joe

[FRC4ME]

Originally Posted by jhersh

Have you reported all the bugs you found so that the library can be improved for everyone? Even better would be patches that implement the fixes.

Visit http://firstforge.wpi.edu/sf/tracker...wpilib/tracker to report bugs!

Thanks,
-Joe

Does the Java tracker actually get used? I noticed that, unlike the C++ tracker which has twelve bugs, the Java tracker only has one; the one that I submitted this January and has still not been fixed. Perhaps this is because, at least when I submitted that one, no Java developers' names were in the assignment list (only C++ and LabVIEW).

I will gladly fix them myself if that is possible. Can you explain further what the process of submitting a patch is? Thanks.

EDIT - I went ahead and submitted the other bugs to the tracker anyway.

[jhersh]

Originally Posted by FRC4ME

Does the Java tracker actually get used? I noticed that, unlike the C++ tracker which has twelve bugs, the Java tracker only has one; the one that I submitted this January and has still not been fixed. Perhaps this is because, at least when I submitted that one, no Java developers' names were in the assignment list (only C++ and LabVIEW).

I will gladly fix them myself if that is possible. Can you explain further what the process of submitting a patch is? Thanks.

EDIT - I went ahead and submitted the other bugs to the tracker anyway.

Sounds good...

I'm not sure why the Java guys aren't on the list. I can address the issues as well, if you don't find one.

If you fix them yourself, you can attach patchs to the artifacts and we'll apply them.

-Joe

[ksanger]

I joined Mak211 last year, three weeks before the ship date. The night before we had crashed our kicker as members had removed parts to modify without telling me. Kick, (too far), bend the forward bracket and eliminated the encoder so the return to reload the kick went back (too far) and destroyed the sensor telling it to stop. The morning of shipping we rebuilt the kicker.

But the most difficult part was that our position sensors on our four wheel steering kept coming loose. Plus we had no means of adjusting the wheels to a known starting position. After shipping we used a spare Crio to figure out how to make a Can Jaguar go from position control to speed control so we could rotate the wheels while reading the pots and displaying their position on the Dashboard. (Last year we were using C++ and to reconfigure the Cans we needed to destruct them then initialize them in either diagnostic speed mode or run position mode). I don't know if I can destruct them in Java and haven't seen a Java example that enables position mode.

Did I mention that I've never coded for C++ objects before? I have been using C since 1980, and I've only read about C++ before and I don't code for a living. Its amazing that we're teaching students Java for next year. Objects rule. Its going to be a while before I'm confident enough to write my own though. Maybe if I had the source I could modify that, but I haven't found the Java wpilibj source.

[davidthefat]

Oh silly me...

Servos

Yep thats right, servos... It took me a full week to figure out that the jumpers existed -__-... It was not software, but hardware so I guess it doesn't count?

[Anupam Goli]

Besides not being able to compile on any x64 OS?

I'd have to say IO. I remember that our head Programmer designed an IO Handler and wrote about half of an OS just so we could start designing our drive system, and autonomous never worked with the IOHandler.

That and the Vision systems. Maybe it was me, but after 4 hours of just trying to get the display to work on the classmate, nothing budged.

[jhersh]

Originally Posted by ksanger

(Last year we were using C++ and to reconfigure the Cans we needed to destruct them then initialize them in either diagnostic speed mode or run position mode).

This year the API has a changeMode method so you don't need to destroy the object and recreate it. Just call changeMode and then call enable.

Originally Posted by ksanger

I don't know if I can destruct them in Java and haven't seen a Java example that enables position mode.

In Java, there are no destructors and there is no delete. The lack of destructors is a limitation of the Squawk JVM that we are using. Objects with no references to them are destroyed by the garbage collector.

-Joe

[rrossbach]

Originally Posted by ksanger

Maybe if I had the source I could modify that, but I haven't found the Java wpilibj source.

FYI the wpilibj source is installed when you install the FRC plugins in Netbeans. The default location is %UserProfile%\sunspotfrcsdk\lib\WPILibJ\src (and the WPILibJ directory contains the Netbeans project for building the library).

- Ron
Team #2607 controls mentor