JTree : Java Glossary

Jtree also lets you edit data about the nodes, add new nodes and prune. You use the TreeModel interface implemented by DefaultTreeModel to manage your tree data. You change the tree by poking the TreeModel, not by poking the TreeNodes directly. You can also use TreeNodes independent of a display, though most algorithmic tree handling is done with specialised classes.

Note that it is spelled
JTree not J tree.

Debugging

• Failing to fire the appropriate change events (e.g. fireValueChanged, fireTreeStructureChanged) in your add and similar TreeModel methods to let Swing know what needs to be repainted.
• When you modify the TreeModel with a Thread other than the Swing Thread, you must do most of your JTree and TreeModel calls with SwingUtilities, including firing changes via invokeLater from other Threads. You further need locks in the TreeModel to deal with the problem of Swing accessing the model at the same time the app is changing it.

Sorting

1. Do a breadth first traversal of the tree.
2. At each node extract a list of the childen into an array.
3. Sort the array.
4. If all is well, that part of the tree is already in order. If not, delete the children, leaving the early ones (if any) which are already in order, then re-add the out of order ones in sorted order. Don’t fire any change events yet.
5. When you have sorted the entire tree, fire a tree structure change event on the root.

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