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From David Jencks <david_jen...@yahoo.com>
Subject Re: I'm going to break "automatic" tomcat jsf support for a couple of days
Date Thu, 15 Mar 2007 18:10:34 GMT

On Mar 15, 2007, at 2:01 PM, Paul McMahan wrote:

> One more thing I just thought of, regarding adding the myfaces classes
> directly to a webapp's classloader...
>
> The JSF 1.2 spec says :
> "Note that Faces is a part of the Java EE platform as of Faces 1.2. A
> web application
> therefore does not need to bundle a Faces implementation anymore when
> it runs on a web
> container that is Java EE technology compliant. Should a Faces
> implementation be
> bundled with a web-application, it will simply be ignored as the Faces
> implementation
> provided by the platform always takes precedence."
>
> This prompted me to add org.apache.myfaces.* to the list of
> non-overrideable classes for webapps deployed into tomcat or jetty.
> javax.* was of course already in that list.  See
> tomcat6-deployer/src/plan/plan.xml:73 and
> jetty6-deployer/src/plan/plan.xml:91.   If we move the myfaces classes
> from the parent config to the webapp's classloader then would this
> configuration of non-overrideable classes actually prevent them from
> being seen?

I think it will still work but it might be better to add these to the  
non-overridable bits of defaultEnvironement in the myfaces MBE.
>
> Earlier on when I first started looking at myfaces I was seeing lots
> of problems due to jasper and myfaces living in separate classloaders.
> I think there are some assumptions about having a relatively flat
> classloader hierarchy in the overall myfaces/jasper/tomcat design that
> can lead to some difficulties in a more complex classloader like
> Geronimo's.

I haven't seen any problems that look like they are coming from this  
with the jetty integration... we'll see with tomcat soon

thanks
david jencks

>
> Best wishes,
> Paul
>
> On 3/15/07, Paul McMahan <paulmcmahan@gmail.com> wrote:
>> On 3/15/07, David Jencks <david_jencks@yahoo.com> wrote:
>> > > Also, do you intend to add the myfaces classes directly to the
>> > > webapp's classloader instead of the current approach which  
>> relies on
>> > > them being available in a parent configuration of the tomcat  
>> and jetty
>> > > configs?  If so then we could reconsider the specialized
>> > > MultiParentClassLoader searching for TLDs that we have in  
>> place right
>> > > now.  We might end up deciding to leave that in place but we  
>> should at
>> > > least think about it...
>> >
>> > That's my intention, and can you point me to the searching code you
>> > are talking about?
>>
>> The specialized TLD searching code that I am referring to was  
>> introduced here:
>> http://svn.apache.org/viewvc?view=rev&revision=517712
>>
>> The basic problem was that by default Jasper looks for TLDs in the
>> webapp's classloader and then looks for TLDs in its parent
>> classloaders by calling ClassLoader.getParent().    This technique
>> works in standalone tomcat and in other containers that have simpler
>> ClassLoader structure.  But in Geronimo this technique does not  
>> locate
>> the JSF TLDs in classloaders of the webapp's parent configurations
>> because those classloaders can only be reached via Geronimo's
>> MultiParentClassLoader.getParents().
>>
>> If we now decide to add the MyFaces jars (and their dependencies?)
>> directly to the webapp's classloader at deployment time then I think
>> Jasper's default technique for locating TLDs might suddenly work.   
>> But
>> that doesn't necessarily mean we should remove the specialized TLD
>> searching that Geronimo now provides to Jasper because it allows
>> Jasper to find, for example, the JSTL TLD in a webapp's parent
>> configurations.
>>
>> Best wishes,
>> Paul
>>


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