[EMAIL PROTECTED]">You definitely miss a framework with a high degree of reusability, entensability and a high degreeChristoph Henrici wrote:I have been studying, testing and playing around with cocoon in the
last few days as a newcomer : i am greatly impressed with what ease with
cocoon "pipelines" arbrary data sources can be "chained" to a result
target: a very powerful paradigm (pipe) applied in a powerful context
(http) by using great technology (xml, xlst).
Yep, I think you really hit the point. Some people believe that it's
enough to add server side transformation capabilities (say, adding a
XSLT post-processor as a servlet filter!) to come up with a publishing
framework.
But without a solid and well designed internal component architecture
this is definately not true.
of configurability achieved through the component architecture. It' s like with all, you start with solving
specific problems and as your requirement space grows you evolve at least the paradigm: good software has
to make well balanced decisions between meeting specific requirements and generic solutions. I think cocoon 2
achieves this extremly well, especially now with the understanding of your below elaborations.
[EMAIL PROTECTED]">Yes, i agree now, understanding very much more about the two approaches to aggregation.In context of the
development of a web based application with requirements for a fairly
generic mechanism for the dynamic personlization of webpages in terms of
content and style the following questions below arised. Maybe they stem
from the fact, that i still missed a couple of aspect and points, maybe
the requirement or idea is just not thought through enough, anyway:
a. Is it possible to "compose" pipelines and having the composed
pipeline beeing processing bottom-up and the whole beeing rendered for
example as html: A compostion of tables within table, frames within
frame etc., where the content of the "elementary" pipelines are
dyanmic, taking for examples data from the databases. I am aware that
the aggregation <map:aggregate> mechansim provides a somewhat similiar
construction, only the composition could also be composed of aggregations.
There are two 'flavors' of aggregation in Cocoon: generation-based and
transformation-based.
The first is done with the use of the <aggregate> semantic include in
the sitemap. In fact, an aggregator is nothing but a special generator,
but it was decided to place directly into the sitemap semantics since it
is very useful.
The problem with this approach is that the parts must be defined at
sitemap-design time. While this normally covers 90% of the cases, in
some other cases (my-netscape-like portal applications, for example) the
aggregation is driven by environment information (say: user preferences)
thus cannot be specified in the sitemap (unless everything is aggregated
and then filtered out, but this is not performant at all, expecially for
very complex portals).
For this reason, another solution is present, which is based on
server-side xinclude expansion performed at a transformat ion stage.
In short: the pipeline contains some namespaces that indicate 'include'
behavior and the transformer acts as an aggregator but on 'part'
information which is previously generated, so might come from any
source.
it is easy to imagine a generator that gets the details about the user
preferences out of a session bean (or ejb, database, file, whatever) and
streams them on the pipe, letting the subsequent transformer performing
the aggregation.
of course, all this is cache-aware.b. Is it possible the change the sitemap or more specifically the
piplines configuration ( <map:pipelines>) dynamically.
No and I will continue to veto it until somebody changes my mind.
I think dynamic pipelines are *bad* and so far, nobody was able to come
up with a meaningful example that *required* dynamic pipelines and
couln't be done with better pipeline components.
[EMAIL PROTECTED]">I'll do that ....combined with the generator based approach, maybe even combined with aIf this can be achieved with cocoon 2 i would be very grateful for a
rough outline on how.
Check the XIncludeTransformer and the CIncludeTransformer.
aggregation / filter approach ......
[EMAIL PROTECTED]">Yep, definitely.If some additional development would be needed it
would be great to have some starting hints at where to start looking at.
Any other ideas or suggestions with regard to the requirement are also
greatly appreciatedHope this helps.
Christoph Henrici
[EMAIL PROTECTED]">
