Jtree - Problem creating a very large one

Question

Hi,
I need to create a multi-level JTree that is very large (aroung 600-650 nodes all in all). At present I am doing the same by creating DefaultMutableTreeNodes and adding them one by one to the tree. It takes a very long time to complete(obviously).
Is there any way of doing this faster? The tree is being constructed from run-time data.
Thanks in advance,
Regards,
Achyuth

Answer 1

Two thoughts. First, I create 100's of nodes and it's pretty fast. It could be how you are creating/adding them. Make sure your code is not the bottleneck. If you are traversing the entire tree or some other odd way of doing it, it could be the problem. I only say that because I am able to create an object structre, parse XML as I create that structe and create all the nodes and its less than 1 second on a PIV 1.7Ghz system. Maybe on slower systems its a lot slower, but for me its up immediately.
Another way, however, is to keep a Map of "paths" to child items in memory. As you build your object from whever, use a Map to keep path info. Now, add listeners to the tree for expand/collapse. Each time it is about to expand, build up the nodes and add them to the expanding node at that point. If it collapses, discard them. This does one of two things. First, for large trees, you aren't wasting tons of time building the tree at the start, and more so, its probably likely that all those nodes aren't going to be expanded/shown right away. Second, it conserves resources. If your tree MUST open in a fully epxanded state, well, then you may be out of luck. But I would much prefer epxanding and building the child nodes at that moment, rather than do the whole thing first.