Learning Java

The idea of my Rasch-Itembank open-source project at java.net is to produce a large numeracy estimation item bank, which updates the estimated difficulty parameters in real time, as it is used. To work properly, the client needs to generate items from the item bank according to the latest item difficulty estimation. The most reliable current working version of my Java Math Test client is a complete cheat. It has absolutely no connection with a database, it is ISP hosted, and it usually works first time, as long as the user has the JRE installed. A second version, hosted by me , is a partial cheat. It connects to a database to record performance data, but it uses hard coded arrays of items, whose difficulty has been estimated from static data collected in the past. This version is less reliable for many reasons. I don't always have the server turned on, I don't always have the database turned on, and sometimes my IP address changes. The conundrum is that to...

For a couple of reasons I have made some structural changes to my remote code store, or repository. First, if I want other people to contribute, I need to make it easy to understand what goes where. Secondly, I wanted to play around a bit more with subversion (svn) commands. My first task was to create some new directories. When I read the book , it looked as if you used svn commands just like DOS or "shell" commands, and instead of them. So I tried: svn add "my documents\code\100515\client" without having first created the client subdirectory. But it didn't work. The wording given by the --help switch makes it clearer: svn add --help add: Put files and directories under version control, scheduling them for addition to repository. usage: add PATH... In other words the add command brings a folder under the svn umbrella, but it cannot be used to create one. Next I wanted to move some source files from the trunk to the new subdirectory. T...

I think I was a little too cryptic in my blog entitled Posting Source Code . I referred back to it when I needed to update the source code on my project site , and found it fell short of being helpful. I shall try to be a bit more explicit in describing how I checked out what was in the repository, and after making some changes, updated it. When first using CollabNet Subversion I made the mistake of cluttering my home computer with the server. I am on a new machine now, and I took care to get the command-line client from the CollabNet Download page. After installing the client, I was pleasantly surprised to observe that it ran happily from my Windows home directory. That is in stark contrast to Java, which requires paths to be set up by the user. The command I needed to download my code into a working directory was svn checkout URL [PATH] --USERNAME where URL is location of my repository and PATH is the path to the local directory. My URL is: https://java.net/p...