Trees - The Definitive Guide to Java Swing - page 661

TreeSelectionModel selectionModel = tree.getSelectionModel();
selectionModel.setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);

If you're interested in finding out the selected path (or paths), you can ask the JTree
directly. You don't need to get the selected path from the model.

TreeSelectionListener Interface and TreeSelectionEvent Class
When the set of selected nodes within a tree changes, a TreeSelectionEvent is generated
and any registered TreeSelectionListener objects of the TreeSelectionModel are notified.
The TreeSelectionListener can be registered either with the JTree or directly with the
TreeSelectionModel . The interface definition follows.

public interface TreeSelectionListener implements EventListener {
public void valueChanged(TreeSelectionEvent treeSelectionEvent);
}

TreePath Class
The last major class to examine is TreePath . It has been used in many of the earlier examples in
this chapter. It describes a read-only collection of nodes that map a path from the root node to
another node, where the root could be the top of a subtree versus the root of the whole tree.
Although two constructors exist to create TreePath objects, you'll normally deal with them only
as the return value from a method. You can also create a new path by adding an element to an
existing TreePath with public TreePath pathByAddingChild(Object child) .
A TreePath can be thought of as an Object array, in which the first element of the array is
the root of the tree and the last element is called the last path component . In between are all the
components connecting them. Normally, the elements of the array will be of type TreeNode .
However, because TreeModel supports objects of any type, the path property of TreePath is
defined to be an array of Object nodes. Table 17-7 lists the four TreePath properties.

Table 17-7. TreePath Properties

Property Name Data Type Access

lastPathComponent Object Read-only

parentPath TreePath Read-only

path Object[ ]

Read-only

pathCount int Read-only

To better understand TreePath , let's reuse the tree traversal sample tree from Figure 17-18,
shown once more in Figure 17-20.