import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.filechooser.*;
import javax.swing.tree.*;
/*
* HTMLFrame - used for PART 3 of CSE 214 HW 3
*
* YOU MUST FILL IN THE CODE FOR THE FOLLOWING TWO METHODS:
* - initTreeData
* - generateHTMLText
*/
public class HTMLFrame extends JFrame implements ActionListener, TreeSelectionListener
{
// tree DISPLAYS OUR TREE, HANDLING ALL RENDERING
private JTree tree = new JTree();
private JScrollPane treeScrollPane = new JScrollPane(tree);
// treeManager IS THE TREE-MANAGING CLASS, YOU WILL DEAL MAINLY
// WITH THIS OBJECT AND IT'S NODE OBJECTS (type DefaultMutableTreeNode)
private DefaultTreeModel treeManager = (DefaultTreeModel)tree.getModel();
// GUI CONTROLS IN THE NORTH
private JPanel northPanel = new JPanel();
private JLabel tagLabel = new JLabel("HTML Tags:");
private String[] htmlTags = { "",
"
",
"",
"",
"",
"",
"
",
"
"
};
private JComboBox tagChoices = new JComboBox(htmlTags);
private String addTagCommand = "Add Tag";
private JButton addTagButton = new JButton(addTagCommand);
private String removeCommand = "Remove";
private JButton removeButton = new JButton(removeCommand);
private String previewCommand = "Preview";
private JButton previewButton = new JButton(previewCommand);
// RIGHT SIDE OF THE SCREEN WHERE WE CAN CHANGE HTML CONTENT
private JPanel centerPanel = new JPanel();
private JPanel northCenterPanel = new JPanel();
private String setContentCommand = "Set Content";
private JButton setContentButton = new JButton(setContentCommand);
private JTextArea textArea = new JTextArea();
private JScrollPane textAreaScrollPane = new JScrollPane(textArea);
/*
* DO NOT CHANGE THIS METHOD
*
* Default Constructor, it starts all the initialization of the tree,
* including calling your initTreeData method.
*/
public HTMLFrame()
{
super("HTMLFrame");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setExtendedState(MAXIMIZED_BOTH);
tree.setModel(treeManager);
layoutGUI();
initTreeData();
}
/*
* DO NOT CHANGE THIS METHOD
*
* This method places all the GUI components in their proper places.
*/
public void layoutGUI()
{
northPanel.add(tagLabel);
northPanel.add(tagChoices);
northPanel.add(addTagButton);
northPanel.add(removeButton);
northPanel.add(previewButton);
centerPanel.setLayout(new BorderLayout());
centerPanel.add(northCenterPanel, BorderLayout.NORTH);
centerPanel.add(textAreaScrollPane, BorderLayout.CENTER);
northCenterPanel.add(setContentButton);
add(northPanel, BorderLayout.NORTH);
add(treeScrollPane, BorderLayout.CENTER);
add(centerPanel, BorderLayout.EAST);
addTagButton.addActionListener(this);
removeButton.addActionListener(this);
previewButton.addActionListener(this);
setContentButton.addActionListener(this);
setContentButton.setEnabled(false);
tree.addTreeSelectionListener(this);
tree.setRootVisible(true);
textArea.setColumns(30);
textArea.setLineWrap(true);
textArea.setWrapStyleWord(true);
}
/*
* DO NOT CHANGE THIS METHOD
*
* This method makes sure user selections of tree nodes
* runs smoothly.
*/
public void valueChanged(TreeSelectionEvent e)
{
TreePath path = e.getNewLeadSelectionPath();
if (path != null)
{
Object node = path.getLastPathComponent();
String contents = node.toString();
if (contents.startsWith("<"))
setContentButton.setEnabled(false);
else
{
setContentButton.setEnabled(true);
textArea.setText(contents);
}
}
}
/*
* YOU MUST DEFINE THIS METHOD
*
* This method should build the default starting tree. It's
* structure should be a basic Web document:
*
*
*
* Title Text
* <body>
* <p>
* ParagraphText
*
* Note that I did not include end tags (like </html>), it is
* not necessary to store that data in our nodes, but when the Web
* page is generated using your generateHTMLText, make sure you don't
* forget them.
*/
public void initTreeData()
{
// ADD YOUR CODE HERE
}
/*
* DO NOT CHANGE THIS METHOD
*
* This method responds to user input.
*/
public void actionPerformed(ActionEvent ae)
{
String command = ae.getActionCommand();
// ADD A TAG TO THE TREE
if (command.equals(addTagCommand))
{
TreePath treePath = tree.getSelectionPath();
// NO NODE IS SELECTED IN THE TREE, SO WE CAN't ADD IT
if (treePath == null)
{
JOptionPane.showMessageDialog( this,
"You must select a parent node!",
"No parent node selected",
JOptionPane.WARNING_MESSAGE);
return;
}
// A NODE IS SELECTED, LET'S TRY TO ADD A CHILD TO IT
else
{
// GET THE SELECTED NODE
DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode)(treePath.getLastPathComponent());
String nodeText = (String)selectedNode.getUserObject();
// WE ARE ONLY ALLOWED TO ADD CHILDREN TO THE body & p NODES
if (nodeText.equals("<body>") || nodeText.equals("<p>"))
{
// WHAT tag ARE WE TRYING TO ADD?
String tag = (String)tagChoices.getSelectedItem();
// WE DON'T WANT ANY NESTED TAGS
if (nodeText.equals(tag))
{
JOptionPane.showMessageDialog( this,
"You may not add that node there!",
"Illegal Operation",
JOptionPane.WARNING_MESSAGE);
return;
}
else
{
// CONSTRUCT OUR NEW NODE
DefaultMutableTreeNode nodeToAdd = new DefaultMutableTreeNode();
nodeToAdd.setUserObject(tag);
// ADD IT TO THE TREE MODEL
treeManager.insertNodeInto(nodeToAdd, selectedNode, selectedNode.getChildCount());
// IF IT'S A PARAGRAPH WE NEED A SECOND NODE
// FOR THE TEXT INSIDE
if (tag.equals("<p>"))
{
DefaultMutableTreeNode textNode = new DefaultMutableTreeNode();
textNode.setUserObject("Paragraph Text");
treeManager.insertNodeInto(textNode, nodeToAdd, 0);
tree.scrollPathToVisible(new TreePath(nodeToAdd.getPath()));
}
// IF IT'S A HEADER TAG WE NEED A SECOND NODE
// FOR THE TEXT INSIDE
else if (tag.startsWith("<h") && (!tag.equals("<hr />")))
{
DefaultMutableTreeNode textNode = new DefaultMutableTreeNode();
textNode.setUserObject("Header Text");
treeManager.insertNodeInto(textNode, nodeToAdd, 0);
tree.scrollPathToVisible(new TreePath(nodeToAdd.getPath()));
}
else
{
// MAKE SURE OUR NEW NODE IS ON DISPLAY
tree.scrollPathToVisible(new TreePath(nodeToAdd.getPath()));
}
}
}
}
}
// THE USER WANTS TO REMOVE A NODE
else if (command.equals(removeCommand))
{
// WHICH NODE?
DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode)(tree.getSelectionPath().getLastPathComponent());
String nodeText = (String)selectedNode.getUserObject();
// THESE NODES CANNOT BE REMOVED
if ( selectedNode.isRoot() ||
nodeText.equals("<body>") ||
nodeText.equals("<head>") ||
nodeText.equals("<title>") ||
(nodeText.charAt(0) != '<') )
{
JOptionPane.showMessageDialog( this,
"You may not remove that node!",
"Illegal Operation",
JOptionPane.WARNING_MESSAGE);
return;
}
else
{
// TAKE IT OUT OF THE TREE MODEL
DefaultMutableTreeNode parentNode = (DefaultMutableTreeNode)selectedNode.getParent();
treeManager.removeNodeFromParent(selectedNode);
tree.scrollPathToVisible(new TreePath(parentNode.getPath()));
}
}
// THE USER WANT'S TO VIEW THE WEB PAGE THE WAY IT
// WOULD BE SEEN INSIDE A WEB BROWSER
else if (command == previewCommand)
{
JDialog dialog = new JDialog();
dialog.setSize(new Dimension(800,600));
dialog.setLocation(100, 100);
dialog.setTitle("HTML Preview");
// WE ARE CALLING YOUR METHOD HERE. YOUR METHOD SHOULD
// GENERATE PERFECT HTML
String webPageText = generateHTMLText((DefaultMutableTreeNode)treeManager.getRoot());
JEditorPane webViewer = new JEditorPane("text/html", webPageText);
JScrollPane webScroller = new JScrollPane(webViewer);
dialog.add(webScroller);
dialog.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
dialog.setVisible(true);
}
// THE USER WANTS TO CHANGE SOME CONTENT
else if (command == setContentCommand)
{
String text = textArea.getText();
DefaultMutableTreeNode selectedNode = (DefaultMutableTreeNode)(tree.getSelectionPath().getLastPathComponent());
selectedNode.setUserObject(text);
treeManager.nodeChanged(selectedNode);
}
}
/*
* YOU MUST DEFINE THIS METHOD
*
* This method will walk the tree and build a String that will ultimately
* be a perfectly constructed Web page. Don't forget to add closing tags.
*
* Note, <br /> and <hr /> don't have closing tags.
*/
public String generateHTMLText(DefaultMutableTreeNode node)
{
// ADD YOUR CODE HERE
}
public static void main(String[] args)
{
HTMLFrame frame = new HTMLFrame();
frame.setVisible(true);
}
}