Prentice.Hall.Introduction.to.Java.Programming,.Brief.Version.9th.(2014).[sharethefiles.com]

27 jtaOutput.append("\nProcessing a single path\n");
28 jtaOutput.append("# of elements: " + path.getPathCount());
29 jtaOutput.append("\nlast element: "
30 + path.getLastPathComponent());
31 jtaOutput.append("\nfrom last node in the path to the root: ");
32 TreeNode node = (TreeNode)path.getLastPathComponent();
33 while (node != null) {
34 jtaOutput.append(node.toString() + " ");
35 node = node.getParent();
36 }
37 }});
38
39 jbtShowPaths.addActionListener(new ActionListener() {
40 @Override
41 public void actionPerformed(ActionEvent e) {
42 jtaOutput.append("\nProcessing multiple paths\n");
43 javax.swing.tree.TreePath[] paths = jTree.getSelectionPaths();
44 for (int i = 0; i < paths.length; i++)
45 jtaOutput.append(paths[i].toString() + "\n");
46 }});
47 }
48 }
The getSelectionPath() method invoked from a JTree returns a
TreePath in line 25. The first node in the path is always the
root of the tree. The getPathCount() invoked from a TreePath
returns the number of the nodes in the path (line 27). The
getLastPathComponent() invoked from a TreePath returns the last
node in the path (line 29). The return node type is Object. You
need to cast it to a TreeNode (line 31) in order to invoke the
getParent() method from a TreeNode (line 34).
While the getSelectionPath() method (line 25) returns the first
selected path, the getSelectionPaths() method (line 41) returns
all the selected paths in an array of paths.
40.13 Case Study: Modifying Trees
Write a program to create two trees that display the same
contents: world, continents, countries, and states, as shown in
Figure 40.28. For the tree on the left, enable the user to choose
a selection mode, specify whether it can be edited, add a new
child under the first selected node, and remove all the selected
nodes.
(a)
(b)
Figure 40.28
You can rename a node, add a child, and remove nodes in a tree
dynamically.
44