Re: How to learn to cope with Jrex - are there tutorials out there?

Billy,

Here's what I did.  It's not elegant, but it might
give you some idea.  I did a lot of this through
experimentation, so it probably isn't the best way.

I have a class with three methods:  doTree(), doElement(),
and doTagEnd().  doTree recursively walks the DOM.  doElement()
is called when a tag is found.  doTagEnd() is called
at the end of that tag.  In this class, I merely print
beginning and ending tags and ignore any tag attributes.  I
then override doElement() and doTagEnd() in a subclass
to do real work.

I get the document and call a recursive method called
doTree():

	 Document doc = navigation.getDocument() ;
	 Element ex = doc.getDocumentElement() ;
	 doTree((Node) ex) ;

doTree() looks like this:

    public void doTree(Node node) {
       if(node instanceof Element) {
	 Element element = (Element) node ;

	 // Visit tag.

	 doElement(element) ;

	 // Visit all the children, i.e., tags contained in this tag.

	 NodeList nl = element.getChildNodes() ;
	 if(nl == null) return ;
	 int num = nl.getLength() ;
	 for(int i=0; i<num; i++)
	    doTree(nl.item(i)) ;

	 // Process the end of this tag.

	 doTagEnd(element) ;
       }
    }

doElement() just prints the tag name:

    public void doElement(Element element) {
       System.out.println("<" + element.getTagName() + ">") ;
    }

and doTagEnd() prints the closing tag:

    public void doTagEnd(Element element) {
       System.out.println("</" + element.getTagName() + ">") ;
    }

To get tag attributes, I used Element.getAttributeNode().

I'm planning on posting a complete example on benjysbrain.com,
but who knows when that will happen?

I haven't looked at putting the browser inside an existing
frame.  Perhaps someone else has an example.

Benjy


Billy wrote:
> Hi,
> thanks Benjy!
> That works great. But there are still some problems left:
> I got a JRexCanvas and a WebNavigation object. I know how to 
> invoke webpages. Myproblem now is the DOM. I got the w3c.org 
> Docoument by webnavi.getDocument(). What can I do with that
> docoment now? How to traverse it and extract the HTML-code?
> Additionally do you know how to invoke URIs inside a frame?
> I dont want to create frames, instead I want to invoke site
> inside of existing ones. Thank you again!
> Bestar regards
> Billy