Hi John and Stefan,
I've made some significant research into this issue that I was having with
the parse-rss plugin and found out the following:
1) What John mentioned about moving the commons-feedparser to the latest
version of Jaxen seems to work (and I did have to hack the feedparser code
to play with the new version of Jaxen). I used jaxen-{core,jdom}.jar.
Further, I was able to verify that moving jdom.jar into the top level lib
directory for Nutch alleviates the weird error that I was having about not
being able to find the org/jdom/Document class within my RSS Parser plugin.
2) * More Importantly *, I'm starting to believe that:
My parse-rss plugin was having a namespace conflict with another jar
file, specifically it may be having a conflict with the the dom4j jar file
in the top level nutch lib directory. I noticed that the version of dom4j
being used by Nutch is currently version 1.4 which happens to have a lot of
the jaxen class files included in it. The newest version of the dom4j jar
file (version 1.5.2) does not have these Jaxen core files in it. I think
that entirely makes sense to not have the jaxen core files within the dom4j
jar, because it appears that the plugins aren't playing in their own sandbox
with respect to their classloaders, and because of this, I think that it's
possible that anyone who uses some parts of the Jaxen API in their plugins
will also have namespace conflicts like me. By placing the newest dom4j jar
file (version 1.5.2) in the top level lib directory for Nutch, my problem
goes away. Of course, I would need to do full testing to ensure that the
dom4j 1.5.2 is still fully compatible with the Nutch API.
So, to sum up a long story, I will try to do some independent research and
identify:
1. Whether it makes sense (and doesn't break anything of course) to upgrade
the dom4j version in Nutch from 1.4 to 1.5.2?
2. If this was actually the root cause of my plugin problem?
Thanks for all of your help!
Cheers,
Chris
On 3/28/05 10:41 AM, "John X" <[EMAIL PROTECTED]> wrote:
> On Mon, Mar 28, 2005 at 09:42:01AM -0800, Chris Mattmann wrote:
>> Hi Stefan,
>>
>> Thanks so much for your efforts. I'll stand by and see if I can investigate
>> it more in parallel as well.
>
> One approach is to use dom4j instead of jdom.
> That requires hack in feedparser.
> I believe it's also bad idea to use jaxen-full.jar
> (use jaxen-core.jar plus a more specific jaxen dom jar)
> Do you really need commons-httpclient-3.0-beta1.jar (and possibly others)?
>
> John
>
>>
>> Thanks again!
>>
>>
>> Cheers,
>> Chris
>>
>>
>>
>> On 3/28/05 9:37 AM, "Stefan Groschupf" <[EMAIL PROTECTED]> wrote:
>>
>>>> On another level, I think it would important for the Nutch project to
>>>> discover why I'm receiving the error in my parse-rss plugin, because
>>>> as John
>>>> X seems to have discovered as well, I don't think it's something that
>>>> is a
>>>> trivial error, and on the other hand, I don't think it's something
>>>> either
>>>> that a user has a low probability of encountering when developing a
>>>> plugin
>>>> with Nutch. I think in fact, that I didn't really do anything out of
>>>> the
>>>> ordinary when going about developing my parse-rss plugin, and I think
>>>> that a
>>>> lot of users are going to be stumped when they are building plugins for
>>>> Nutch if we don't track this error, identify its cause, and remedy it.
>>>>
>>> Now since John posted your code link I will have a closer look, I was
>>> guessing you just need an rss parser and not to write a rss parser. :-)
>>> I agree that we need to fix bugs and I will try to do until next week
>>> depending how difficult it is to fix.
>>>
>>> Stefan
>>>
>>
>> ______________________________________________
>> Chris A. Mattmann
>> [EMAIL PROTECTED]
>> Staff Member
>> Modeling and Data Management Systems Section (387)
>> Data Management Systems and Technologies Group
>>
>> _________________________________________________
>> Jet Propulsion Laboratory Pasadena, CA
>> Office: 171-266B Mailstop: 171-246
>> Phone: 818-354-8810
>> _______________________________________________________
>>
>> Disclaimer: The opinions presented within are my own and do not reflect
>> those of either NASA, JPL, or the California Institute of Technology.
>>
>>
>>
>>
>>
>>
> __________________________________________
> http://www.neasys.com - A Good Place to Be
> Come to visit us today!
______________________________________________
Chris A. Mattmann
[EMAIL PROTECTED]
Staff Member
Modeling and Data Management Systems Section (387)
Data Management Systems and Technologies Group
_________________________________________________
Jet Propulsion Laboratory Pasadena, CA
Office: 171-266B Mailstop: 171-246
Phone: 818-354-8810
_______________________________________________________
Disclaimer: The opinions presented within are my own and do not reflect
those of either NASA, JPL, or the California Institute of Technology.
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