On Wed, 12 May 2010, Julian Maibaum wrote:
Christian Heimes, Dirk Rothe, and I have jcc-wrapped bobo-browse
(http://code.google.com/p/bobo-browse/) in order to add faceted search
capabilities to PyLucene. However, the two modules don't play well together,
as wrappers from PyLucene cannot be used in a bobo-browse context and vice
versa.
What is the best way to get classes from two different jcc python extension
modules to interact?
I've noticed that when there is overlap in Java classes between two
JCC-built extensions, these kinds of errors occur. One can imagine that if
the classes have the same name but are not from the same codebase that funny
version conflicts might arise, for example.
But I haven't looked into exactly what the problem is but a simple
workaround is to just create one extension that combines both Lucene and
Bobo-browse. Take the JCC invocation for PyLucene from its Makefile and add
the things would want from Bobo-browse you want from it and you should have
something that works better.
Andi..
Setup:
X64 Ubuntu 9.10 Python 2.6 Tried both versions:
JCC-2.4.1-py2.6-linux-x86_64.egg compiled with --shared
JCC-2.5.1-py2.6-linux-x86_64.egg compiled with --shared
Tried both versions:
lucene-2.9.1-py2.6-linux-x86_64.egg
lucene-2.9.2-py2.6-linux-x86_64.egg
bobobrowse-2.5.0_rc1-py2.6-linux-x86_64.egg
Both the bobo-browse python extension module and PyLucene are attached to the
main python thread and have been initialized using their respective initVM
methods.
I have attached the makefile (modified from PyLucene) that was used to build
bobo-browse.
#---- START CODE ----
import bobobrowse as bb
import lucene
import os
CLASSPATH = os.pathsep.join((lucene.CLASSPATH, bb.CLASSPATH)
lucene.initVM(CLASSPATH)
bb.initVM(CLASSPATH)
typeHandler = bb.MultiValueFacetHandler("type")
placeHandler = bb.MultiValueFacetHandler("id")
facetHandlers = lucene.JArray('object')(2, bb.FacetHandler)
facetHandlers[0] = typeHandler
facetHandlers[1] = placeHandler
reader = bb.IndexReader.open('/path/to/my/lucene/index', True)
facetHandlers = bb.Arrays.asList(facetHandlers)
indexReader = bb.BoboIndexReader.getInstance(reader, facetHandlers)
#---- END CODE ----
Expected:
The example code above works - java objects from classes wrapped as part of
the PyLucene module can transparently be used by other python extension
modules such as bobo-browse.
Experienced:
Throws Errors:
Traceback (most recent call last):
File "./dynamic/vls/search/facets.py", line 115, in <module>
test()
File "./dynamic/smc/jcc/__init__.py", line 52, in wrapper
return func(*args, **kwargs)
File "./dynamic/vls/search/facets.py", line 57, in test
facetHandlers = lucene.JArray('object')(2, bb.FacetHandler)
ValueError: <type 'FacetHandler'>
and
bobobrowse.InvalidArgsError: (<type 'BoboIndexReader'>, 'getInstance',
(<IndexReader: org.apache.lucene.index.directoryowningrea...@30419d05>,
<List: [com.browseengine.bobo.facets.impl.multivaluefacethand...@3f829e6f,
com.browseengine.bobo.facets.impl.multivaluefacethand...@2980f96c]>))
respectively.
The Errors can be avoided by changing the corresponding lines in the example
above to:
facetHandlers = bb.JArray('object')(2, bb.FacetHandler)
reader = bb.IndexReader.open('/path/to/my/lucene/index', True)
However, this only works because lucene's IndexReader is referenced by
bobo-browse and has therefore been wrapped at build-time. At later stages
other lucene classes are needed to work with bobobrowse that no wrappers have
been built for (e.g. QueryParser). I understand that jcc can be forced to
built and include wrappers for e.g. org.apache.lucene.queryParser.QueryParser
that are then accessible for use with classes from the bobo-browse module as
e.g 'bobobrowse.QueryParser'. The most simple solution is calling jcc with an
additional --jar lucene.jar parameter - in effect leading to lucene being
installed twice: First self-contained PyLucene module and, second, as part of
bobo-browse in the flat bobo-browse module namespace. This is not quite
desirable:
Since
bb.IndexReader.class_ == lucene.IndexReader.class_
--> class org.apache.lucene.index.IndexReader, anyways, it would arguably be
more intuitive to be able to use the available wrappers in the context of
other jcc modules even if they have not specifically been forced into that
other module. Is there any way to obtain the desired behavior?
Thank you very much and all the best,
Julian Maibaum
j.maibaum(at)semantics.de
s<e>mantics GmbH
http://www.semantics.de
