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From Lars Huttar <>
Subject DTD validation
Date Fri, 05 Sep 2008 22:08:36 GMT
Resending as text instead of html, per request from David Crossley.
Apologies -- I don't remember why I thought the HTML formatting was 


A couple of years ago I asked for help getting DTD validation to work 
with Cocoon 2.1.8.
I got some information but it didn't solve the problem, and I was left 
with "try looking through the code or running in a debugger".
That exchange is included below.[1]

The same error occurs in 2.1.11 when I try to validate with a DTD.
The codebase is too large for me to analyze... especially for a 
framework that is supposed to be usable "often without any required 
programming." I've tried running Cocoon in a debugger but have been 

Others have asked about DTD validation. E.g. [2]. But apparently no 
results were forthcoming.

This is really surprising to me, given that Cocoon is built around XML 
pipelines, and DTD is the only kind of schema language defined as part 
of the XML standard.

Granted, XML Schema is more powerful, and more modern. But for our 
simple needs, and I'm sure others' too, XML Schema is like using 
Mathematica to compute 2 + 2. DTD expresses the grammar much more 
efficiently, for the simple cases. (For corner cases, we use Schematron, 
which we are able to make work manually because it only requires XML and 
XSLT, which Cocoon handles well.)

I'm all for supporting XML Schema and Relax NG, but for Cocoon not to 
support DTD's at all just seems baffling.

Can any of you Cocoon developers take a look at this please?

Unfortunately, we're pretty well tied to Cocoon 2.1.* for now... 2.2 
seems to be too big of a structural change for our code base, and 3.0 
all the more so.
I realize some will be less than motivated to integrate this into the 
older 2.1.* branch.
But we have a lot of time and code invested in Cocoon 2.1, so I thought 
it was worth asking.

At the very least, if someone could tell me authoritatively "no, this is 
not supported in Cocoon", then I could prune one branch of the search 
for solutions.

Back in 2005, Pier Fumagali wrote 
> This finishes the "validation" block and its implementation. It 
> provides two transformers: one filtering in-line and failing on 
> errors, and one producing a report.
> Relax-NG is implemented using Jing.
> XML-Schema is implemented using the JAXP API supplied with Cocoon ... 
> DTD is currently not supported, although it would be trivial to do it 
> with the Xerces supplied with Cocoon. 
I would love to know whether this ever happened... or if not, how to 
supply the trivial missing piece to make it happen.



Subject: 	Re: *DTD* validation: "Unsupported grammar language"Link to 
this message <>
From: 	Joerg Heinicke (
Date: 	12/20/2006 04:09:49 PM
List: 	org.apache.*cocoon*.dev

just from having a look at the code: 1. It's (see Validator interface and its declared 
constants). 2. This exception is thrown in 
AbstractValidator.getValidationHandler() in line 327 in the current 
code. It is thrown when no SchemaParser can be found. 3. Grammars and 
their parsers seem to be configured via Configurable.configure(). So 
maybe the javadoc for this method [1] is helpful. Otherwise you might 
need to have a look into the code of this method or do some debugging.

Regards Jörg


On 19.12.2006 18:32, Lars Huttar wrote:

Hello, I seconded this question on the *Cocoon* user list but have not 
received a response, so would like to ask the developers. In *Cocoon* 
2.1.9, we are trying to use ValidationReportTransformer to validate our 
XML against a *DTD*. I'm looking at the documentation at 

The validation sample block has examples for validating against RNG and 
XML Schema, but not against a *DTD*. Like José quoted below, I'm trying 
to figure out how to make it work. Here's my attempt, a copy-and-modify 
of a match pattern in samples\blocks\validation\sitemap.xmap:
<map:match pattern="report-*dtd*-valid">
  <map:generate src="source-ok.xml"/>
  <map:transform type="*validation-report*" src="schema-ok.*dtd*">
    <map:parameter name="grammar" value="" />
  <map:transform src="context:/stylesheets/system/xml2html.xslt"/>

I added the "grammar" parameter, as instructed by the documentation 
referenced above, to the *validation-report* transformer. For grammar 
identifier, the documentation seemed to indicate I should use 
"". (I also tried "*dtd*" just for kicks.) 
But the result is that I get the error 
Unsupported grammar language

Does this mean there is no support for validating against DTDs? Or am I 
doing something wrong?

Thanks, Lars

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