…but I just handed my debugging crown to him.
Kris and I have been banging our heads on our desks because of problems we’re having with our JTreeTables. A JTreeTable is a class that we found on a Sun Java forum that combines the attributes of the JTable with a JTree – basically giving you JTree behaviour with columnar (table) data. It’s really handy. But frequently, and often in cases I could easily reproduce, the damn thing wasn’t updating correctly. Kris and I both made sure that our updates were properly protected by synchronization locks, and the events were being fired in the event loop, lessons we’ve both learned by hard experience. But it was still acting strangely. Kris spent a lot of time reading forum posts, running the debugger down deep in Java library code, and basically working this problem from all angles for days upon days.
Yesterday he found the problem. And the problem was in my code. When you fire an event, you need to give it an array of Objects that starts at the root node of the tree, and follows down through the tree to the node that actually changed. But of course, when you actually change a node, you’re already at the node that changed, and it’s pretty easy to trace up from node.parent() to node.parent() until you reach the top, so that’s what I do. And then I attempt to reverse the order of what I’ve got to make the required array. But it appears that I fundamentally misunderstood the Stack class, because pushing objects on the Stack and then doing a “toArray” on it doesn’t reverse the order, as I’d thought. So the view was getting a totally messed up event, and that was messing everything else up.
Kris changed my Stack.push into ArrayList.add(0, node), and everything works now. And I never thought about doing it that way because I thought List.add(0, Object) would replace the object at position 0, not push them all up.
And Kris’s small change (after big effort) closes three bug reports assigned to me, and a bunch that were assigned to him.
In my defence, I’d actually come up with the Stack thing while Vicki was driving us to Pittsburgh. So perhaps it wasn’t my best work.