Am 12.07.2011 10:39, schrieb Francesco Chicchiriccò:
On 11/07/2011 23:25, Lars Huttar wrote:
Robby,
Thanks for your reply.
It's nice to see another instance of the conditional and error-handling
sitemap structures.
However we still have a contradiction with section 2.1.1 of the
documentation [1], and it doesn't seem certain to me which is going to
"win".
The "linear pipelines" / "no conditionals" statement, AFAIK, is new to
Cocoon 3.0. So if indeed C3 is intended to continue to allow and support
conditionality in pipelines, then we have to conclude that
(a) the "linear pipelines" idea was discussed, and decided upon, and
added to the documentation, but
(b) then it was rejected, but has not yet been removed from the
documentation.
If on the other hand section 2.1.1 is correct, then we can assume that
(a) the "linear pipelines" idea was discussed, and decided upon, and
added to the documentation, but
(b) the consequent changes to the Cocoon code and samples have not all
been made yet, but will be in the future.
It seems to me that the latter is a little more plausible (that a
decision has been made but its ramifications have not yet been applied
throughout the project) than the former (that a decision was made,
documented, and reversed, but not yet de-documented).
It would be very helpful to hear a definite statement from a Cocoon
committer or PMC member, before implementing an application that relies
on conditional pipelines, which may later disappear.
Lars,
a brief outlook to the docbook source of the page [1]
svn info
http://svn.apache.org/repos/asf/cocoon/cocoon3/trunk/cocoon-docs/src/docbkx/reference/pipelines.xml
states that this document was last modified by Reinhard in January 2010.
I became member of the PMC more than one year afterwards, so I cannot
be completely sure. but I can suppose that the documentation is simply
outdated since:
1. there are no issues on JIRA about marking as deprecated or
about removing support for "non-linear" stuff
2. the documentation probably refers to the Pipeline (Java) API
That second point is indeed true.
The Pipeline API itself does not support conditionals, loops or things
like that.
A pipeline is constructed, filled with components and then executed.
That execution will use all the components in the pipeline.
The sitemap on the other constructs pipelines on demand.
It can and does use conditionals to decide what pipeline to construct
and which components to add in which order.
If you are used to using a sitemap and intend to stay with that approach
you should find everything you need.
You could take a look at the unit tests / samples for the sitemap
modules to see what is possible and what not.
HTH,
Steven
Anyway, I do believe that the definitive answer can only come from
Reinhard, currently on holiday for a couple of weeks more.
Reinhard will be back next week...
Regards.
[1]http://cocoon.apache.org//3.0/reference/html/pipelines.html#d0e88
On 7/11/2011 3:42 PM, Robby Pelssers wrote:
Hi Lars,
if you take a look at the cocoon-sitemap module you will see all supported
nodes:
- act
- error
- generate
- match
- otherwise
- parameter
- pipeline
- pipelines
- read
- select
- serialize
- sitemap
- transform
- when
So I think you're good to go with C3.
Kind regards,
Robby
-----Oorspronkelijk bericht-----
Van: Lars Huttar [mailto:[email protected]]
Verzonden: ma 11-7-2011 21:41
Aan: Cocoon Users List
Onderwerp: Cocoon 3 - no conditional pipelines?
Hi,
As we look at porting one of our applications from Cocoon 2.1 to 3.0,
one thing I saw causes me concern [1]:
A Cocoon 3 pipeline always goes through the same sequence of
components to produce its output. There is no support for
conditionals, loops, tees or alternative flows in the case of errors.
The reason for this restriction is simplicity and that non-linear
pipelines are more difficult (or even impossible) to be cached. In
practice this means that a pipeline has to be contructed completely at
build-time.
If non-linear XML pipes with runtime-support for conditionals, loops,
tees and error-flows are a requirement for you, see the XProc
<http://en.wikipedia.org/wiki/XProc> standard of the W3C. There are
several available implementations for it.
Is this still true, that Cocoon 3 pipelines cannot have conditionals or
error flows? or is that obsolete?
Our application occasionally uses<map:select> and<map:handle-errors>,
so this could be an indication that Cocoon 3 will not meet our needs.
On the other hand, the sitemap at
cocoon-all-3.0.0-alpha-3\src\cocoon-sample\src\main\resources\COB-INF\sitemap.xmap
has both<map:select> and<map:handle-errors> in it.
So maybe that sitemap does not represent a sitemap that will work with
Cocoon 3.0? In that case, is there any sample sitemap that will work
with C3? That was the only sample sitemap I had found (except the one
under cocoon-profiling, which has barely anything in it).
Thanks,
Lars
[1]http://cocoon.apache.org//3.0/reference/html-single/index.html#d0e88
--
Francesco Chicchiriccò
Apache Cocoon Committer and PMC Member
http://people.apache.org/~ilgrosso/
