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From "Mattmann, Chris A (388J)" <chris.a.mattm...@jpl.nasa.gov>
Subject Re: Creating a custom product query handler for webgrid
Date Wed, 08 Dec 2010 21:19:17 GMT
Haha, *Kale*, forever the optimist.

I'll make a prediction: we'll figure out a way to solve this (for Dave and Rishi)! :) And
when we do, we'll post it back here to the list ^_^

There is something going on with Dave's setup, b/c, for whatever reason (like I stated in
this earlier email [1]), the setup seemed to work fine for me...

Cheers,
Chris

[1] http://s.apache.org/1P8

On Dec 8, 2010, at 11:44 AM, David Kale wrote:

> Rishi,
> 
> I'll make a prediction: nothing will work other than directly copying the
> JAR file into WEB-INF/lib.
> 
> This is something I've run into with using external JAR files to provide
> jdbc drivers (for both Oracle and SQL Server dbs), and we have yet to
> resolve it (i.e., no matter where I put it, referencing it from the config
> page simply does not work).  There is something bizarre going on with the
> handling of JAR files in the config page's "code base."  I suppose it's time
> to file a bug.
> 
> Dave
> 
> 
> On Mon, Dec 6, 2010 at 10:08 AM, Mattmann, Chris A (388J) <
> chris.a.mattmann@jpl.nasa.gov> wrote:
> 
>> Hi Rishi,
>> 
>> (cc to dev@oodt)
>> 
>> Thanks much. I think that the issue is that you were referencing a JAR in
>> 1a that was actually within tomcat's lib directory which caused tomcat to
>> mess up. Typically I include web-grid code base jars *outside* of the realm
>> of Tomcat which I think can confuse its own classloader from Web-Grid's.
>> Copying the jar to WEB-INF/lib within Web-Grid will work, but it's not a
>> best practice IMHO. So try next time redo-ing 1a and 1b but putting the jar
>> outside of tomcat (e.g., in /usr/local/co2cdx/jarname or something) and see
>> if that works...HTH!
>> 
>> Cheers,
>> Chris
>> 
>> On Dec 6, 2010, at 10:00 AM, Verma, Rishi (317I) wrote:
>> 
>>> Hi Chris,
>>> 
>>> Thanks for the help! I got it working per with some more playing around.
>> It looks like the problem had to do with referencing my custom query handler
>> JAR within webgrid, which you suggested might be incorrect.
>>> 
>>> My old (incorrect) referencing setup:
>>> 1a) Added an entry to webgrid conf page's "Code Base" form, pointing to
>> my JAR located within tomcat/lib
>>> 1b) Added an entry to webgrid conf page's "Product Query Handlers" form,
>> pointing to the name of my handler class:
>> "gov.nasa.jpl.co2.cdx.hdf5.HDF5GetMetHandler"
>>> 
>>> My new (correct) referencing setup:
>>> 2a) Removed the entry within webgrid conf page's "Code Base" form,
>> pointing to my JAR located within tomcat/lib
>>> 2b) Kept the entry within webgrid conf page's "Product Query Handlers"
>> form, pointing to the name of my handler class:
>> "gov.nasa.jpl.co2.cdx.hdf5.HDF5GetMetHandler"
>>> 2c) Placed my JAR within webgrid/WEB-INF/lib
>>> 
>>> This brings up the question, is the correct procedure to always copy
>> custom query handler JARs to WEB-INF/lib (ie. 2a-2c)? Or is it to somehow
>> use the "Code Base" form entry to point to the JAR? The latter does not seem
>> to work for me given [1a-1b] configuration setup.
>>> 
>>> By the way, I just checked in the code + pom to:
>> http://oodt.jpl.nasa.gov/repo/projects/co2portal/trunk/cdx/hdf5met
>>> * Quick note on the pom, it won't build properly the first time since I
>> haven't configured the workaround you suggested. I just manually installed
>> the Apache OODT dependency jars to my local repository for now.
>>> 
>>> Also, for the contextual purposes, below is the error I was receiving
>> from the query handler when invoked via HTTP call:
>>> 
>>> java.lang.ClassCastException: gov.nasa.jpl.co2.cdx.hdf5.HDF5GetMetHandler
>> cannot be cast to org.apache.oodt.product.handlers.ofsn.OFSNGetHandler
>>> 
>> org.apache.oodt.product.handlers.ofsn.util.OFSNObjectFactory.getGetHandler(OFSNObjectFactory.java:91)
>>> 
>> org.apache.oodt.product.handlers.ofsn.OFSNFileHandler.getGetHandler(OFSNFileHandler.java:206)
>>> 
>> org.apache.oodt.product.handlers.ofsn.OFSNFileHandler.query(OFSNFileHandler.java:126)
>>> 
>> org.apache.oodt.grid.ProductQueryServlet.handleQuery(ProductQueryServlet.java:59)
>>>       org.apache.oodt.grid.QueryServlet.doPost(QueryServlet.java:100)
>>>       org.apache.oodt.grid.QueryServlet.doGet(QueryServlet.java:75)
>>>       javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
>>>       javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
>>> 
>>> Thanks!
>>> Rishi
>>> 
>>> 
>>> On Dec 2, 2010, at 7:12 PM, Mattmann, Chris A (388J) wrote:
>>> 
>>> Hi Rishi,
>>> 
>>> Is this code checked in? Can I see your POM and how you are integrating
>> this code into web-grid? Are you referencing it as a Jar file from the web
>> grid conf page? Or, are you actually dropping a Jar into WEB-INF/lib within
>> web-grid, and if so, what jar?
>>> 
>>> Cheers,
>>> Chris
>>> 
>>> P.S. Feel free to ask questions like this on the dev@oodt.apache.org
>> <mailto:dev@oodt.apache.org> list. I think it would be great! Feel free to
>> repost there!
>>> 
>>> On Dec 2, 2010, at 5:09 PM, Verma, Rishi (317I) wrote:
>>> 
>>> Hi Chris, Mike
>>> 
>>> This is kind of a low-level coding question, but I wonder if either of
>> you could help out. I made a custom query handler (attached) that extends
>> StdOFSNGetHandler and tried to run it within webgrid. This class does not do
>> anything special, but should return a prod file when queried from webgrid
>> via REST just like StdOFSNGetHandler does.
>>> 
>>> However, when trying to run my query handler from webgrid, I receive a
>> class cast exception from the framework (attached).
>>> 
>>> I made sure to register the query handler within my
>> org.apache.oodt.product.handlers.ofsn.xmlConfigFilePath file as below:
>>> <handler name="HDF5Met" type ="get"
>> class="gov.nasa.jpl.co2.cdx.hdf5.HDF5GetMetHandler"/>
>>> 
>>> To test the handler out, I tried issuing the following query:
>>> 
>> http://localhost:8080/webgrid-apache/prod?q=OFSN=/subdirectory/testfile.h5+AND+RT%3DHDF5Met
>>> 
>>> Do you have any tips on why I might be getting a ClassCastException?
>>> 
>>> Thanks!
>>> Rishi
>>> 
>>> 
>>> 
>>> 
>> <HDF5GetMetHandler.java><ATT00001..htm><webgrid_error.html><ATT00002..htm>
>>> 
>>> 
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> Chris Mattmann, Ph.D.
>>> Senior Computer Scientist
>>> NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA
>>> Office: 171-266B, Mailstop: 171-246
>>> Email: chris.a.mattmann@nasa.gov<mailto:chris.a.mattmann@nasa.gov>
>>> WWW:   http://sunset.usc.edu/~mattmann/<http://sunset.usc.edu/%7Emattmann/>
>>> Phone: +1 (818) 354-8810
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> Adjunct Assistant Professor, Computer Science Department
>>> University of Southern California, Los Angeles, CA 90089 USA
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> 
>>> 
>> 
>> 
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> Chris Mattmann, Ph.D.
>> Senior Computer Scientist
>> NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA
>> Office: 171-266B, Mailstop: 171-246
>> Email: chris.a.mattmann@nasa.gov
>> WWW:   http://sunset.usc.edu/~mattmann/<http://sunset.usc.edu/%7Emattmann/>
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> Adjunct Assistant Professor, Computer Science Department
>> University of Southern California, Los Angeles, CA 90089 USA
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> 
>> 


++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Chris Mattmann, Ph.D.
Senior Computer Scientist
NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA
Office: 171-266B, Mailstop: 171-246
Email: chris.a.mattmann@nasa.gov
WWW:   http://sunset.usc.edu/~mattmann/
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Adjunct Assistant Professor, Computer Science Department
University of Southern California, Los Angeles, CA 90089 USA
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


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