Partial Selection in JTree using checkbox for every node

I have a application which uses a JTree. For each n开发者_Python百科ode in the tree, there is a checkbox attached to the node using a customized TreeCellRenderer. When some items of a node are selected i.e not all children of a node are selected using the chechboxes, how do i indicate using the checkbox of the parent node that only a partial list of nodes is selected. For this, i need to draw a little square in the checkbox indicating that it is partially selected.

You can use e.g. http://www.roseindia.net/javatutorials/tristatecheckbox.shtml or http://www.javaspecialists.co.za/archive/Issue082.html