35.6. JSP Directives

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31.14. Tree Events

JTree can fire TreeSelectionEvent and TreeExpansionEvent , among many other events. Whenever a new node is selected, JTree fires a TreeSelectionEvent . Whenever a node is expanded or collapsed , JTree fires a TreeExpansionEvent . To handle the tree selection event, a listener must implement the TreeSelectionListener interface, which contains a single handler named valueChanged method. TreeExpansionListener contains two handlers named treeCollapsed and treeExpanded for handling node expansion or node closing.

The following code displays a selected node:

 void valueChanged(TreeSelectionEvent e) {   TreePath path = e.getNewLeadSelectionPath();   TreeNode treeNode = (TreeNode)path.getLastPathComponent();   System.out.println(   "The selected node is "   + treeNode.toString()); }