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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,Medievel,Ancient,Philosophers;
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.SOUTH);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(400, 300);
setVisible(true);
}
private void addPhilosopher() {
DefaultMutableTreeNode parent = getSelectedNode();
System.out.println(parent);
if (parent == null) {
JOptionPane.showMessageDialog(ModelJTree.this, "Select an area.", "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",true);
rootNode.add(medieval);
return rootNode;
}
public static void main(String args[]) {
new ModelJTree();
}
}
">Hi....My question is In a JTree i want to add nodes to only the nodes whose parent is root node.Please help me with this.In the following code it should be possible to add node to "Medieval" but not "socrates.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,Medievel,Ancient,Philosophers; 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.SOUTH); setDefaultCloseOperation(EXIT_ON_CLOSE); setSize(400, 300); setVisible(true); } private void addPhilosopher() { DefaultMutableTreeNode parent = getSelectedNode(); System.out.println(parent); if (parent == null) { JOptionPane.showMessageDialog(ModelJTree.this, "Select an area.", "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",true); rootNode.add(medieval); return rootNode; } public static void main(String args[]) { new ModelJTree(); }}
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Difference between include directive and script tag while including Java scripts file in JSP.
I was trying to use JavaScript file for validations of the fields and buttons in my JSP page.
but found that the following worked:
and not:
I wanted to know the reason?
Thanks in advance!!
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Comparison between Servlets and CGI Scitpting technologies.
A CGI scripts is a program that is written in C,C++,or Perl.A CGI script gets executed in a server.When a aserver receives a request from the client for processing data,the server passes the request to the CGI script.The CGI script processes the request and sends the output in the form of HTML to the server.The server in turn passess the request to the client.The disadvantages of using a CGI script...
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Which are following are considered threadsafe ?
Context attributes / class variables / local variables / request attributes
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Filters in Real Time projects
Which method we can use to run the thread continuously? What are the filters in Real Time projects on which way we can use?
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