Thursday, September 30, 2010

JProc 0.5

I've just released version 0.5 of JProc, which allows you to access Solaris data from java applications.

I was hoping for a few more features, but encountered a fairly nasty bug, and it was more than worth fixing that straight away.

Basically, you get the data from /proc by opening files in the /proc filesystem and reading data from them. I was doing the open(), but there was a distinct lack of close() associated with each one. A massive file descriptor leak ensued.

The one neat feature that made it was the ability to select which columns are visible in the process viewer. This involved a little fiddling with the Model underlying the JTable. Essentially, all I had to do was add an array of visible columns, each element of which maps to a real column. So I can have only some of the columns visible, and could re-order them if that's desired. The only tricky bit I had trouble with is that I have custom renderers for some of the columns (so that times and sizes are shown in human-friendly terms), and fiddling with the columns completely lost the custom renderers, forcing me to have to re-apply the renderers any time I change the structure.

I've hidden a few of the less commonly used columns by default, which helps by making the viewer less cluttered. There's still room for improvement, especially in the area of aggregation and filtering - areas where top and prstat are so-so.

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