Add and remove tree Node and expand the tree node
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
public class ModelJTree extends JFrame {
private JTree tree;
private DefaultTreeModel model;
private DefaultMutableTreeNode rootNode;
public ModelJTree() {
DefaultMutableTreeNode philosophersNode = getPhilosopherTree();
model = new DefaultTreeModel(philosophersNode);
tree = new JTree(model);
JButton addButton = new JButton("Add Philosopher");
addButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
addPhilosopher();
}
});
JButton removeButton = new JButton("Remove Selected Philosopher");
removeButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
removeSelectedPhilosopher();
}
});
JPanel inputPanel = new JPanel();
inputPanel.add(addButton);
inputPanel.add(removeButton);
Container container = getContentPane();
container.add(new JScrollPane(tree), BorderLayout.CENTER);
container.add(inputPanel, BorderLayout.NORTH);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(400, 300);
setVisible(true);
}
private void addPhilosopher() {
DefaultMutableTreeNode parent = getSelectedNode();
if (parent == null) {
JOptionPane.showMessageDialog(ModelJTree.this, "Select an era.", "Error",
JOptionPane.ERROR_MESSAGE);
return;
}
String name = JOptionPane.showInputDialog(ModelJTree.this, "Enter Name:");
model.insertNodeInto(new DefaultMutableTreeNode(name), parent, parent.getChildCount());
}
private void removeSelectedPhilosopher() {
DefaultMutableTreeNode selectedNode = getSelectedNode();
if (selectedNode != null)
model.removeNodeFromParent(selectedNode);
}
private DefaultMutableTreeNode getSelectedNode() {
return (DefaultMutableTreeNode) tree.getLastSelectedPathComponent();
}
private DefaultMutableTreeNode getPhilosopherTree() {
DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("Philosophers");
DefaultMutableTreeNode ancient = new DefaultMutableTreeNode("Ancient");
rootNode.add(ancient);
ancient.add(new DefaultMutableTreeNode("Socrates"));
DefaultMutableTreeNode medieval = new DefaultMutableTreeNode("Medieval");
rootNode.add(medieval);
return rootNode;
}
public static void main(String args[]) {
new ModelJTree();
}
}
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