/* Demonstrate a tree events 
 */
 
 import java.awt.*;
 import javax.swing.*;
 import javax.swing.event.*;
 import javax.swing.tree.*;
 
 class TreeEventDemo
 {
 	JLabel jlab;
 
 	TreeEventDemo()
 	{
 		// Create a new JFrame container
 		JFrame jfrm = new JFrame("Tree Event Demo");
 
 		// Use the default border layout manager
 
 		// give the frame an initial size
 		jfrm.setSize(200, 200);
 
 		// terminate program when the user closes the application
 		jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
 		// create a label that will display the tree selection
 		jlab = new JLabel();
 
 
 		/* Begin creating the tree be defining the
 		 * structure and realtionship of its nodes*/
 
 		// First, create the root node of the ttree 
 		DefaultMutableTreeNode root = new DefaultMutableTreeNode("Food");
 
 		/* Next, create twoo subtrees. One contains fruit.
 		 * The other vegetables.*/
 
 		// Create the root of the Fruit subtree
 		DefaultMutableTreeNode fruit = new DefaultMutableTreeNode("Fruit");
 		root.add(fruit); // add the Fruit node to the tree
 
 		/* The Fruit subtree has two subtrees on its own.
 		 * The first is Apples, the second is Pears.*/
 
 		// Create an Apples subtree
 		DefaultMutableTreeNode apples = new DefaultMutableTreeNode("Apples");
 		fruit.add(apples);
 
 		/* Populate the Apples subtree by adding 
 		 * apple varieties to the Apples subtree*/
 		apples.add(new DefaultMutableTreeNode("Jonathan"));
 		apples.add(new DefaultMutableTreeNode("Winesap"));
 
 		//Create a Pears subtree
 		DefaultMutableTreeNode pears = new DefaultMutableTreeNode("Pears");
 		fruit.add(pears);
 
 		// Populate the Pears subtree
 		pears.add(new DefaultMutableTreeNode("Barlett"));
 
 		// Create the root of the Vegetables subtree
 		DefaultMutableTreeNode veg = new DefaultMutableTreeNode("Vegetables");
 		root.add(veg);
 
 		// Populate Vegetables
 		veg.add(new DefaultMutableTreeNode("Beans"));
 		veg.add(new DefaultMutableTreeNode("Corn"));
 		veg.add(new DefaultMutableTreeNode("Potatoes"));
 		veg.add(new DefaultMutableTreeNode("Rice"));
 
 		/* Now, create a JTree that uses the structure
 		 * defined by the preceding statements*/
 		JTree jtree = new JTree(root);
 
 		// Allow the tree to be edited so that model events can be generated
 		jtree.setEditable(true);
 
 		//Set the tree selection mode to single selection
 		TreeSelectionModel tsm = jtree.getSelectionModel();
 		tsm.setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
 
 		// Finally, wrap the tree in scroll pane
 		JScrollPane jscrlp = new JScrollPane(jtree);
 
 		// Listen for tree expansion events
 		jtree.addTreeExpansionListener(new TreeExpansionListener()
 		{
 			public void treeExpanded(TreeExpansionEvent tse)
 			{
 				// Get the path to the expansion point
 				TreePath tp = tse.getPath();
 
 				// Display the node
 				jlab.setText("Expansion: " + tp.getLastPathComponent() );
 			}
 
 			public void treeCollapsed(TreeExpansionEvent tse)
 			{
 				// Get the path to the expansion point
 				TreePath tp = tse.getPath();
 
 				// Display the node
 				jlab.setText("Collapse: " + tp.getLastPathComponent() );
 			}
 		});
 
 		// Listen for tree selection events
 		jtree.addTreeSelectionListener(new TreeSelectionListener()
 		{
 			public void valueChanged(TreeSelectionEvent tse)
 			{
 				// Get the path to the selection
 				TreePath tp = tse.getPath();
 
 				//Display the selected node
 				jlab.setText("Selection event: " +tp.getLastPathComponent() );
 			}
 		});
 
 		// Listen for tree model events.Notice that the listener is registered with tree model
 		jtree.getModel().addTreeModelListener(new TreeModelListener()
 		{
 			public void treeNodesChanged(TreeModelEvent tse)
 			{
 				// Get the path to the change
 				TreePath tp = tse.getTreePath();
 
 				// Display the Path
 				jlab.setText("Model change path: " + tp);
 			}
 
 			/* Empty implementations of the remaining TreeModelEvent
 			 * methods. Implement these if your application 
 			 * needs to handle these actions*/
 			public void treeNodesInserted(TreeModelEvent tse){}
 			public void treeNodesRemoved(TreeModelEvent tse){}
 			public void treeStructureChanged(TreeModelEvent tse){}
 		});
 
 		// Add the tree and label to the content pane
 		jfrm.getContentPane().add(jscrlp, BorderLayout.CENTER);
 		jfrm.getContentPane().add(jlab, BorderLayout.SOUTH);
 
 		// Display the frame
 		jfrm.setVisible(true);
 	}
 
 	public static void main(String[] args)
 	{
 		SwingUtilities.invokeLater(new Runnable()
 		{
 			public void run()
 			{
 				new TreeEventDemo();
 			}
 		});
 	}
 }