Re: xalan usage in taglibs

[Romain Manni-Bucau]

requires a classloader hack, no other trivial way, and that's why we
removed it from tomee

2017-12-06 14:27 GMT+01:00 Matthew Broadhead <matthew.broadh...@nbmlaw.co.uk>:
> is there any way that i can get the correct xalan at runtime?
>
> to recap this is the code that is blowing up for me:
> Reader xsl = new InputStreamReader(filepath.openStream());
> TransformerFactory transformerfactory = TransformerFactory.newInstance();
> StreamSource ssXsl = new StreamSource(xsl);
> ssXsl.setSystemId(filepath.toExternalForm());
> Templates templates = transformerfactory.newTemplates(ssXsl);
> Transformer transformer = templates.newTransformer();
>
> last line causes:
> java.lang.ClassCastException: org.apache.xml.dtm.ref.DTMManagerDefault
> cannot be cast to org.apache.xml.dtm.DTMManager
> at org.apache.xml.dtm.DTMManager.newInstance(DTMManager.java:137)
> at org.apache.xpath.XPathContext.(XPathContext.java:102)
> at org.apache.xpath.XPathContext.(XPathContext.java:349)
> at org.apache.xpath.XPathContext.(XPathContext.java:337)
> at
> org.apache.xalan.transformer.TransformerImpl.(TransformerImpl.java:397)
> at
> org.apache.xalan.templates.StylesheetRoot.newTransformer(StylesheetRoot.java:200)
>
> maybe you know some way to find the Impl with the correct DTMManager?
>
>
> On 30/11/2017 17:30, Romain Manni-Bucau wrote:
>>
>> 2017-11-30 16:51 GMT+01:00 Jeremy Boynes <jer...@boynes.com>:
>>>>
>>>> On Nov 30, 2017, at 3:14 AM, Matthew Broadhead
>>>> <matthew.broadh...@nbmlaw.co.uk> wrote:
>>>>
>>>> has anything been decided?  if i try to redeploy a context in production
>>>> all my xslt processors blow up.  there should be a solution that fits all?
>>>
>>> Taglibs (both Apache and Glassfish) has always had a dependency on Xalan.
>>> My understanding is that TomEE did not include it and so broke users that
>>> use the XML tags. If so, TomEE should fix that.
>>
>> Sadly this is not a bug on tomee but the best solution we went through
>> after having delivered xalan for some releases. Xalan dependency
>> breaks 80% of apps so no way to include it - and this is the issue of
>> Matthew. Note it also affects simple apps in tomcat including taglib
>> and other libs.
>>
>>> You can probably add Xalan to your TomEE installation somehow to work
>>> around it but how to do that is really a question for the TomEE users list.
>>>
>>> A patch for Taglibs that removes the Xalan dependency and doesn't regress
>>> the #27717 performance fix would be great. A patch that removed the
>>> dependency but regressed performance would have to be evaluated at the time.
>>> The previous decision was not to do that.
>>>
>> -
>> To unsubscribe, e-mail: taglibs-user-unsubscr...@tomcat.apache.org
>> For additional commands, e-mail: taglibs-user-h...@tomcat.apache.org
>>
>

-
To unsubscribe, e-mail: taglibs-user-unsubscr...@tomcat.apache.org
For additional commands, e-mail: taglibs-user-h...@tomcat.apache.org

Re: xalan usage in taglibs

[Romain Manni-Bucau]

2017-11-30 16:51 GMT+01:00 Jeremy Boynes :
>> On Nov 30, 2017, at 3:14 AM, Matthew Broadhead 
>>  wrote:
>>
>> has anything been decided?  if i try to redeploy a context in production all 
>> my xslt processors blow up.  there should be a solution that fits all?
>
> Taglibs (both Apache and Glassfish) has always had a dependency on Xalan. My 
> understanding is that TomEE did not include it and so broke users that use 
> the XML tags. If so, TomEE should fix that.

Sadly this is not a bug on tomee but the best solution we went through
after having delivered xalan for some releases. Xalan dependency
breaks 80% of apps so no way to include it - and this is the issue of
Matthew. Note it also affects simple apps in tomcat including taglib
and other libs.

>
> You can probably add Xalan to your TomEE installation somehow to work around 
> it but how to do that is really a question for the TomEE users list.
>
> A patch for Taglibs that removes the Xalan dependency and doesn't regress the 
> #27717 performance fix would be great. A patch that removed the dependency 
> but regressed performance would have to be evaluated at the time. The 
> previous decision was not to do that.
>

-
To unsubscribe, e-mail: taglibs-user-unsubscr...@tomcat.apache.org
For additional commands, e-mail: taglibs-user-h...@tomcat.apache.org

Re: xalan usage in taglibs

[Romain Manni-Bucau]

2017-11-27 20:01 GMT+01:00 Jeremy Boynes <jboy...@apache.org>:
>> On Nov 27, 2017, at 7:38 AM, Romain Manni-Bucau <rmannibu...@apache.org> 
>> wrote:
>>
>> 2017-11-27 16:31 GMT+01:00 Jeremy Boynes <jboy...@apache.org>:
>>> On Nov 27, 2017, at 12:07 AM, Matthew Broadhead
>>> <matthew.broadh...@nbmlaw.co.uk> wrote:
>>>
>>> In TomEE 7.0.3 everything is fine at startup.  But if a webapp is reloaded I
>>> get
>>> java.lang.ClassCastException: org.apache.xml.dtm.ref.DTMManagerDefault
>>> cannot be cast to org.apache.xml.dtm.DTMManager
>>> and the whole container needs to be restarted which is not ideal during
>>> production
>>>
>>> Now in TomEE 7.0.4 I cannot even start without this error so I cannot
>>> upgrade.
>>>
>>> It seems like a classloader issue but taglibs is the only hardcoded
>>> dependency on xalan
>>>
>>>
>>> Are you including the taglibs jars in your war when deploying to TomEE? You
>>> shouldn’t need to do that as TomEE should be providing its own
>>> implementation of JSTL which would mean there is a chance of conflict if you
>>> also include them.
>>
>> Issue is xalan conflicts very easily in terms of transitive deps.
>>
>>>
>>> From a thread on tomee-users, it sounds like TomEE could be trying include
>>> taglibs and avoid including the Xalan dependency but I wouldn’t expect that
>>> to work as it actually is needed by the XML tags. The dependency is
>>> “provided” scope to avoid automatic transitive inclusion for applications
>>> that don’t use the XML tags (which is most). For container integration it
>>> should be included as an application might use those tags.
>>
>> TomEE bundles taglib and therefore must bundle xalan otherwise several
>> features don't work and TCK don't pass.
>
> That was one of the tradeoffs in fixing #27717. I tried to use pure JAXP and 
> the implementation from the JRE but it had the same issue as the way 1.1 
> worked, perhaps not surprisingly given they are both Xalan based. To avoid 
> rebuilding the DTM for each XPath execution, the tags work the same way an 
> XSLT does, creating the DTM once and then evaluating the expression using the 
> DTM. Unfortunately that meant using the low-level Xalan DTM APIs hence the 
> direct dependency. The trade off doing this was:
>
> a) do nothing, leaving #27717 unresolved
> b) use Xalan as a dependency that was only actually needed if the XML tags 
> were used in an application
> c) shade Xalan and increase the library size when most users wouldn’t need it
> d) refactor the XML tags into a separate taglib from the others so users 
> would need to include multiple libraries
>
> Option b) seemed like a reasonable compromise because:
> - users on a Servlet-profile container would not have JSTL provided by the 
> container and so would control which dependencies they needed
> - users on a Web- or Full-profile container would have the entire JSTL 
> implementation provided by the container and the container vendor would have 
> ensured the dependencies were resolved appropriately

This is where it doesn't work. In tomcat you impose it to be inherited
in the app and therefore conflict 80% of the time :(.

I'd be for option e): support xalan as an optional dependency if
present or fallback on a) if not.

>
>

-
To unsubscribe, e-mail: taglibs-user-unsubscr...@tomcat.apache.org
For additional commands, e-mail: taglibs-user-h...@tomcat.apache.org

Re: xalan usage in taglibs

[Romain Manni-Bucau]

2017-11-27 16:31 GMT+01:00 Jeremy Boynes :
> On Nov 27, 2017, at 12:07 AM, Matthew Broadhead
>  wrote:
>
> In TomEE 7.0.3 everything is fine at startup.  But if a webapp is reloaded I
> get
> java.lang.ClassCastException: org.apache.xml.dtm.ref.DTMManagerDefault
> cannot be cast to org.apache.xml.dtm.DTMManager
> and the whole container needs to be restarted which is not ideal during
> production
>
> Now in TomEE 7.0.4 I cannot even start without this error so I cannot
> upgrade.
>
> It seems like a classloader issue but taglibs is the only hardcoded
> dependency on xalan
>
>
> Are you including the taglibs jars in your war when deploying to TomEE? You
> shouldn’t need to do that as TomEE should be providing its own
> implementation of JSTL which would mean there is a chance of conflict if you
> also include them.

Issue is xalan conflicts very easily in terms of transitive deps.

>
> From a thread on tomee-users, it sounds like TomEE could be trying include
> taglibs and avoid including the Xalan dependency but I wouldn’t expect that
> to work as it actually is needed by the XML tags. The dependency is
> “provided” scope to avoid automatic transitive inclusion for applications
> that don’t use the XML tags (which is most). For container integration it
> should be included as an application might use those tags.

TomEE bundles taglib and therefore must bundle xalan otherwise several
features don't work and TCK don't pass.

>

-
To unsubscribe, e-mail: taglibs-user-unsubscr...@tomcat.apache.org
For additional commands, e-mail: taglibs-user-h...@tomcat.apache.org