JEditorPane parsing HTML

Question

Hi all,
I am using JEditorPane and it's ability to parse HTML, which although is relatively old and crusty is certainly all I need for the job.
Now, I understand there is a chain of classes involved in taking my .html file and turning popping into a something we can see in a JEditorPane. For example, an img tag, is picked up by HTMLEditorKit and turned into an ImageView for display purposes.
I want to do the following: I have subclassed HTMLEditorKit, and have overridden the HTMLFactory (although at the moment it just defers everything to super). I want to be able to pick out all of the html comment tags as they go through the HTMLEditorKit :
<!-- hey hey this is a comment -->... and get to the comment text, "hey hey this is a comment", as a Java string. However I've been digging around with Element for hours now and although my HTMLFactory correctly digs out the comments from the rest of the elements:
else if (kind == HTML.Tag.COMMENT)
                    {System.out.println("I found a comment but don't know what it said!!");... as you can see, I don't know how to get to the comment text itself.
The reason why I want access to the comment text is that I want to supplement the HTML code a little bit and add something in the comment that will affect the way it is rendered when I read it depending on the comment - so there's the reason if curious.
Any help, and I do mean anything at all, would be much appreciated, as this is the last obstacle in my path to getting this thing working :)
Thanks for your time!
- Peter

Answer 1

Here is some old code I have lying around that attempts to iterate through all the elements. If I remember correctly the comment text is found in the AttributeSet of the element:
import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.text.html.*;
class GetHTML
    public static void main(String[] args)
        EditorKit kit = new HTMLEditorKit();
        Document doc = kit.createDefaultDocument();
        // The Document class does not yet handle charset's properly.
        doc.putProperty("IgnoreCharsetDirective", Boolean.TRUE);
        try
            // Create a reader on the HTML content.
            Reader rd = getReader(args[0]);
            // Parse the HTML.
            kit.read(rd, doc, 0);
            System.out.println( doc.getText(0, doc.getLength()) );
            System.out.println("----");
            // Iterate through the elements of the HTML document.
            ElementIterator it = new ElementIterator(doc);
            Element elem = null;
            while ( (elem = it.next()) != null )
                AttributeSet as = elem.getAttributes();
                System.out.println( "\n" + elem.getName() + " : " + as.getAttributeCount() );
                if ( elem.getName().equals( HTML.Tag.IMG.toString() ) )
                    Object o = elem.getAttributes().getAttribute( HTML.Attribute.SRC );
                    System.out.println( o );
                Enumeration enum = as.getAttributeNames();
                while( enum.hasMoreElements() )
                    Object name = enum.nextElement();
                    Object value = as.getAttribute( name );
                    System.out.println( "\t" + name + " : " + value );
                    if (value instanceof DefaultComboBoxModel)
                        DefaultComboBoxModel model = (DefaultComboBoxModel)value;
                        for (int j = 0; j < model.getSize(); j++)
                            Object o = model.getElementAt(j);
                            Object selected = model.getSelectedItem();
                            if ( o.equals( selected ) )
                                System.out.println( o + " : selected" );
                            else
                                System.out.println( o );
                if ( elem.getName().equals( HTML.Tag.SELECT.toString() ) )
                    Object o = as.getAttribute( HTML.Attribute.ID );
                    System.out.println( o );
                //  Wierd, the text for each tag is stored in a 'content' element
                if (elem.getElementCount() == 0)
                    int start = elem.getStartOffset();
                    int end = elem.getEndOffset();
                    System.out.println( "\t" + doc.getText(start, end - start) );
        catch (Exception e)
            e.printStackTrace();
        System.exit(1);
    // Returns a reader on the HTML data. If 'uri' begins
    // with "http:", it's treated as a URL; otherwise,
    // it's assumed to be a local filename.
    static Reader getReader(String uri)
        throws IOException
        // Retrieve from Internet.
        if (uri.startsWith("http:"))
            URLConnection conn = new URL(uri).openConnection();
            return new InputStreamReader(conn.getInputStream());
        // Retrieve from file.
        else
            return new FileReader(uri);
}To test it just use:
java GetHTML somefile.html