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/**
* @version 1.00 1999-07-17
* @author Cay Horstmann
*/
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Enumeration;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.JTree;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;
import javax.swing.tree.TreeSelectionModel;
public class ClassBrowserTest {
public static void main(String[] args) {
JFrame frame = new ClassBrowserTestFrame();
frame.show();
}
}
class ClassBrowserTestFrame extends JFrame implements ActionListener,
TreeSelectionListener {
public ClassBrowserTestFrame() {
setTitle("ClassBrowserTest");
setSize(300, 200);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
// the root of the class tree is Object
root = new DefaultMutableTreeNode(java.lang.Object.class);
model = new DefaultTreeModel(root);
tree = new JTree(model);
// add this class to populate the tree with some data
addClass(getClass());
// set up selection mode
tree.addTreeSelectionListener(this);
int mode = TreeSelectionModel.SINGLE_TREE_SELECTION;
tree.getSelectionModel().setSelectionMode(mode);
// this text area holds the class description
textArea = new JTextArea();
// add tree and text area to the content pane
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(1, 2));
panel.add(new JScrollPane(tree));
panel.add(new JScrollPane(textArea));
Container contentPane = getContentPane();
contentPane.add(panel, "Center");
// new class names are typed into this text
textField = new JTextField();
textField.addActionListener(this);
contentPane.add(textField, "South");
}
public void actionPerformed(ActionEvent event) { // add the class whose name
// is in the text field
try {
String text = textField.getText();
addClass(Class.forName(text));
// clear text field to indicate success
textField.setText("");
} catch (ClassNotFoundException e) {
Toolkit.getDefaultToolkit().beep();
}
}
public void valueChanged(TreeSelectionEvent event) { // the user selected a
// different
// node--update
// description
TreePath path = tree.getSelectionPath();
if (path == null)
return;
DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode) path
.getLastPathComponent();
Class c = (Class) selectedNode.getUserObject();
String description = getFieldDescription(c);
textArea.setText(description);
}
public DefaultMutableTreeNode findUserObject(Object obj) { // find the node
// containing a
// user object
Enumeration e = root.breadthFirstEnumeration();
while (e.hasMoreElements()) {
DefaultMutableTreeNode node = (DefaultMutableTreeNode) e
.nextElement();
if (node.getUserObject().equals(obj))
return node;
}
return null;
}
public DefaultMutableTreeNode addClass(Class c) { // add a new class to the
// tree
// skip non-class types
if (c.isInterface() || c.isPrimitive())
return null;
// if the class is already in the tree, return its node
DefaultMutableTreeNode node = findUserObject(c);
if (node != null)
return node;
// class isn't present--first add class parent recursively
Class s = c.getSuperclass();
DefaultMutableTreeNode parent;
if (s == null)
parent = root;
else
parent = addClass(s);
parent = addClass(s);
// add the class as a child to the parent
DefaultMutableTreeNode newNode = new DefaultMutableTreeNode(c);
model.insertNodeInto(newNode, parent, parent.getChildCount());
// make node visible
TreePath path = new TreePath(model.getPathToRoot(newNode));
tree.makeVisible(path);
return newNode;
}
public static String getFieldDescription(Class c) { // use reflection to
// find types and names
// of fields
String r = "";
Field[] fields = c.getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
Field f = fields[i];
if ((f.getModifiers() & Modifier.STATIC) != 0)
r += "static ";
r += f.getType().getName() + " ";
r += f.getName() + "\n";
}
return r;
}
private DefaultMutableTreeNode root;
private DefaultTreeModel model;
private JTree tree;
private JTextField textField;
private JTextArea textArea;
}
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