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
|
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?
- are there any other viable and simple alternatives?
Thank you for your comments.
Michal
