Working Exclusion
OK, I'm writing this one really late (by 5 days), but here goes...

This was the first day that I felt I was really productive for the release since last weekend. I got a bit done for the release before now, and I got a lot done on the paper with DW and TA, but I have obviously been tired from the Noosa tri. I'll make the effort to take time off after it next year.

This day was spent debugging the excludes code. I finished the port of the ConstraintNegationTuples class to StatementStoreInverseResolution, which was at least enough to make it run. Of course, it didn't work, which meant that I had to sit down and figure out exactly what it was doing. I'd love to put a full description in here, but since I'm having to go back a few days to remember, and because I'm currently a little short on time I'll just let the reader look at the source code and figure it out for themselves.

The first thing to recognise was that there are two situations. The first is if the Metanode (ie. the model) was fixed. When this happens then it is necessary to slice that model out of the statement store in order to do the inversion. This has consequences for the beforeFirst method, as the first integer will always need to match the given model. It also means that the iterator has to be limited to a single model.

The second situation is for a variable metanode. This ranges over the entire datastore, and the code is simpler. There were just a few tricks making sure it worked side-by-side with the fixed metanode case.

Once I had it all running I put it up against the relevant JXUnit tests, and it all worked. I was very happy. :-)

Remote Joins
The next thing to work on was the Remote Resolver tests which were failing. According to the symptoms from ML, it sounded like the join code was failing. I don't know a problem like that would only show up against this particular resolver, but since it does it falls to me to fix it.

Given that it appeared to be "join code" that was at fault, I asked AM for some assistance. He was happy to help, and immediately suggested a logging statement to observe the structure of the constraint expression. The system immediately failed with a NullPointerException. We spent a little time looking for the culprit, but came up with nothing before calling it a day.