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Disposition-Notification-To: =?iso-8859-2?Q?=CFURDINA_Michal?=
 <Michal.Durdina@assetsoft.sk>
Subject: Design of unmarshaling sitemap component
Date: Thu, 29 Jul 2004 09:20:23 +0200
Message-ID: <4C47FFB0CC6A2E4D92550B89B68FC7830170C74D@s2-ba.asset-internal>
Thread-Topic: Design of unmarshaling sitemap component
Thread-Index: AcR1PINxnpxdiThqRxG1zyJuY/UR0A==
From: =?iso-8859-2?Q?=CFURDINA_Michal?= <Michal.Durdina@assetsoft.sk>
To: <dev@cocoon.apache.org>

Hi,
I would like to discuss the design problem of the sitemap component. My =
plan is to develop special let's call it transformer for transforming =
sources for pages written or generated by analysts (model) to dynamic =
pages generating required results (implementation). The form of model is =
custom XML according to given XMLSchema and the implementation pages =
should be in form of jxtemplates (or xsp).

The transformation should go like this:

pipeline:
            additional data
                   |
modelXML -> populated modelXML -> computed model -> jxtemplate source

The intent of the pipeline is to generate executable source from model =
that will generate required dynamic page. The trick is that the computed =
modelXML is not trivial and should be implemented as Java OM. What I =
need to involve is conversion from XML to Java Object, make the =
computation in Java and go back with the results to XML in form of =
jxtemplate source.

I have two alternatives of implementation. Both are involving castor for =
converting XML to Java object.

A.) make the XML2Java conversion in transformer
pipeline:

file(modelXML) -> cinclude(aditionaldata) -> =
castortransformer(modelClass, template) ->

-> jxtemplatetransformer -> jxtemplate (or xsp) source
           |
      modelInstance

This starts with reading modelXML from file, including additional data =
(i.e. in form of another xml document). Populated XML is then the source =
for Castor unmarshaling, the intermediate result is the instance of =
modelClass placed on request attribute. The transformer then emits the =
template given in second parameter. The modelInstance is used in =
template and jxtemplatetransformer is used to generate required page =
source (jxtemplate again or xsp).

B.) make the XML2Java conversion in action:

pipeline1:
action(cocoon:/pipeline2, modelClass) {
	jxtemplategenerator(template) -> jxtemplate (or xsp) source=20
                 |
           modelInstance
}

pipeline2:
file(modelXML) -> cinclude(aditionaldata) -> XML

This is simmilar to A.) but with the exception that this does not break =
the SAX stream in castortransformer and XML2Java conversion is done =
between two pipelines. On the other hand there is useless serialization =
and deserialization between both pipelines.

There is question about which approach is better from the design point =
of view.

Additional questions include:
- in case of A.) is it better to have modelXML on the start of the =
pipeline and template as the parameter or to have template at the start =
of the pipeline and modelXML as the parameter?=20
- are there any other viable and simple alternatives?

Thank you for your comments.
Michal