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Message-ID: <8b8d97d2050212151973d5dcd6@mail.gmail.com>
Date: Sat, 12 Feb 2005 18:19:52 -0500
From: Irv Salisbury <irv.salisbury@gmail.com>
Reply-To: Irv Salisbury <irv.salisbury@gmail.com>
To: dev@cocoon.apache.org
Subject: Re: XMLBeans and request attributes
In-Reply-To: <420E0A39.4070101@nada.kth.se>
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References: <8b8d97d205021111567cee763d@mail.gmail.com>
	 <420E0A39.4070101@nada.kth.se>

On Sat, 12 Feb 2005 14:52:57 +0100, Daniel Fagerstrom
<danielf@nada.kth.se> wrote:
> Irv Salisbury wrote:
> > This is really a follow up to some questions I asked earlier about XML
> > in request attributes.  I wanted to show how I went about solving what
> > I needed, and to get feedback if there is a better way.
> >
> > To recap, my basic problem was that I wanted to call internal
> > pipelines and pass them XML.  The cocoon: protocol does not support
> > POST, so the easiest way I was told to use request attributes.  I
> > decided to incorporate XMLBeans into the mix to make my life easier.
> >
> > So, all of my business objects in the system are XMLBeans that have
> > been generated from a set of XMLSchema files.  I have a series of
> > internal pipelines that can generate XML of these schemas.  To "pass"
> > the objects around, I use a combination of flowscript and a generator
> > I wrote that generates XML from a request attribute that happens to be
> > an XMLObject.  (Borrowing from the RequestAttributeGenerator)
> >
> > So, here is a simple flow snippet:
> >
> >         var sessionInfo = getSessionInfo();
> >       cocoon.request.setAttribute( "sessionInfo", sessionInfo );
> >       cocoon.sendPage( "internal/style/catalog" );
> >
> > So, the goal of the getSessionInfo call is to create a SessionInfo
> > object, which happens to be an XMLBeans object.  Here is the
> > getSessionInfo method:
> >
> >   function getSessionInfo() {
> >       var pipelineUtil = cocoon.createObject( PipelineUtil );
> >         var xmlSaxHandler =
> >               XmlBeans.getContextTypeLoader().newXmlSaxHandler(
> >
> > SessionInfoDocument.type, null );
> >        pipelineUtil.processToSAX(
> >                   "internal/sessionInfo/getSessionInfo",
> >                   null,
> >                   xmlSaxHandler.getContentHandler() );
> >          var sessionInfo = xmlSaxHandler.getObject();
> >       return sessionInfo;
> >   }
> >
> > Then, my generator for internal/style/catalog is such:
> >
> >          <map:generate type="xmlbeansAttribute">
> >            <map:parameter name="attributeName" value="sessionInfo"/>
> >          </map:generate>
> >
> > This really seems to work great.  Has anyone had experience with doing
> > this before?  Does this seem like a good idea?  Anything I am missing
> > here?
> 
> Seem like a reasonable approach. You can simplify things a little bit by
> embeding the XMLBean in an object that implements
> org.apache.excalibur.xml.sax.XMLizable,
> http://svn.apache.org/viewcvs.cgi/excalibur/trunk/components/xmlutil/src/java/org/apache/excalibur/xml/sax/XMLizable.java?view=markup
> The toSAX method could be implemented in terms of the XMLObject.save method.
> 
> Both JXTG and the XModuleSource
> http://wiki.apache.org/cocoon/XModuleSource are XMlizable aware, so you
> don't need any specialized generator.
> 
> Also, if you are using trunk, it might be interesting to know that Rhino
> 1.6, (that is used for flowscripts) has extensive XMLBean support:
> http://marc.theaimsgroup.com/?t=110009028500003&r=1&w=2.
> 
> > The main reason for choosing XMLBeans was the ability to go back and
> > forth from Java - XML easily.  Boy, if this was merged with Hibernate,
> > that would be something!
> 
> They are at least discussing it: http://wiki.apache.org/xmlbeans/V2Features.
> 
> /Daniel
> 

This is why I ask this list!  Thanks for the info.  Great references. 
You know, if only some of this could be put into book form...

Irv