Java Tutorial/Intermediate GUIs/A wiki editor

A wiki editor

This wiki editor is a component based on JPanel that embeds two JEditorPane components, one configured as non-editable display for an HTMLDocument and one as an editor for a PlainDocument, which can be used to edit wiki syntax. A HyperlinkListener is used to track the selection of links in the resulting HTML document. A parser that has yet to be written is meant to translate the wiki syntax to HTML or XML.

Exercises

• Write an ANTLR parser that translates the wiki syntax into an HTML document.
• Use an intermediate XML format as the output of the parser and use XSLT to transform it into an HTML document.
• Add [Edit]-hyperlinks to the HTML document that allow to edit only a single section of the wiki document.
• Improve the parser to allow more Wikipedia syntax.

Source code

package org.wikiversity.java_tutorial;

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.event.HyperlinkEvent;
import javax.swing.event.HyperlinkListener;
import javax.swing.text.PlainDocument;
import javax.swing.text.html.HTMLDocument;
import javax.swing.text.html.HTMLFrameHyperlinkEvent;

public class WikiEditor extends JPanel implements ActionListener
{
	private JPanel documentPanel = new JPanel ();
	private CardLayout cardLayout = new CardLayout ();
	private JEditorPane wiki   = new JEditorPane ();
	private JEditorPane editor = new JEditorPane ();
	private HTMLDocument htmlDocument;
	private PlainDocument wikiDocument;
	private final static String WIKI   = "Wiki"; 
	private final static String EDITOR = "Editor";
	private JButton wikiButton = new JButton ("Wiki"),
	                editorButton = new JButton ("Editor");

	class HyperlinkHandler implements HyperlinkListener
	{ 
            public void hyperlinkUpdate (HyperlinkEvent e)
            {
                if (e.getEventType () == HyperlinkEvent.EventType.ACTIVATED)
                {
            	    try {
            		JEditorPane pane = (JEditorPane) e.getSource ();
            		if (e instanceof HTMLFrameHyperlinkEvent)
            		{
            			HTMLFrameHyperlinkEvent hfe = (HTMLFrameHyperlinkEvent) e;
            			HTMLDocument doc = (HTMLDocument) pane.getDocument ();
            			doc.processHTMLFrameHyperlinkEvent (hfe);
            		}
            		else
            		{
            			pane.setPage (e.getURL ());
            		}
            	   }
            	   catch (Throwable t) {
            		displayError (t);
            	   }
               }
           }
        }
	
	public WikiEditor ()
	{
		setLayout (new BorderLayout ());

		JPanel panel = new JPanel ();
		panel.setLayout (new FlowLayout ());
		wikiButton.addActionListener (this);
		panel.add (wikiButton);
		editorButton.addActionListener (this);
		panel.add (editorButton);
		add (panel, BorderLayout.NORTH);
		
		documentPanel = new JPanel ();
		add (documentPanel, BorderLayout.CENTER);
		documentPanel.setLayout (cardLayout);
		
		wiki.setContentType ("text/plain");
		wiki.setText (WIKI);
		wiki.setEditable (false);
		wikiDocument = (PlainDocument) wiki.getDocument ();
		documentPanel.add (wiki, WIKI);

		editor.setContentType ("text/html");
		editor.setText (EDITOR);
		editor.setEditable (true);
		htmlDocument = (HTMLDocument) editor.getDocument ();
		documentPanel.add (editor, EDITOR);
	}

	public void actionPerformed (ActionEvent e)
	{
		Object src = e.getSource ();
		if (src == wikiButton) {
			showWiki ();
		}
		else if (src == editorButton) {
			showEditor ();
		}
	}

	private void showWiki ()
	{
		cardLayout.show (documentPanel, WIKI);
	}

	private void showEditor ()
	{
		cardLayout.show (documentPanel, EDITOR);
	}

	private void displayError (Throwable t)
	{
		t.printStackTrace ();
	}
	
	public final static void main (String[] args)
	{
		new WikiEditor ().run (args);
	}
	
	public void run (String[] args)
	{
		JFrame frame = new JFrame ("WikiEditor");
		frame.add (this);
		frame.setSize (800, 600);
		frame.setVisible (true);
	}
}