[pylucene-dev] ConstantScoreQuery

[tsuraan at tsuraan.net]

The problem is that I have an automatic query builder that assembles 
Lucene queries based off arbitrary user input.  There are a few 
different filters that are in use, so assembling them as parts of a 
boolean query keeps my code simple; I used to have just one filtering 
action that a user could do, and then I did have different code based 
on whether the user used the filter or not, but once more filters were 
added I found it a lot easier to convert them into queries to be added 
to a boolean query tree.

On Aug 23, 2007, at 11:45 AM, Marc Weeber wrote:

> hi,
>
> The following code works for me:
>
> hope this helps?!
>
> best,
>
> Marc
>
>
> ----------------
>
>
> class AssociationFilter(object):
>     """
>     create a PyLucene Query filter to compute an association score 
> between two items
>
>     """
>
>     def __init__(self, source, target):
>         self._source = source
>         self._target = target
>
>     def bits(self, reader):
>         bits = PyLucene.BitSet(reader.maxDoc())
>         for id in [self._source, self._target]:
>         	termDocs = reader.termDocs(PyLucene.Term('uid', id))
>         	docs, freqs = termDocs.read(1)
>         	if len(docs) == 1:
>         		bits.set(docs[0])
>         return bits
>
>
> filter = AssociationFilter(queryID, answerID)
> hits = searcher.search(query, filter)
>
>
>
> On 23-aug-2007, at 17:19, tsuraan at tsuraan.net wrote:
>
>> Is it possible to create a ConstantScoreQuery using a python-defined 
>> filter?  I'm trying the following, and I get the pasted error:
>>
>> >>> class MyFilter(object):
>> ...  def bits(self, reader):
>> ...   return BitSet()
>> ...
>> >>> f=MyFilter()
>> >>> q=ConstantScoreQuery(f)
>> Traceback (most recent call last):
>>   File "<stdin>", line 1, in ?
>> pybackend.thirdparty.PyLucene.lnxpyd.PyLucene.InvalidArgsError: 
>> (<type 'PyLucene.ConstantScoreQuery'>, '__init__', 
>> (<__main__.MyFilter object at 0xb7cda14c>,))
>>
>>
>> So, my other thought was maybe I need to inherit from the PyLucene 
>> Filter object, but that doesn't work either:
>>
>> >>> class MyFilter(Filter):
>> ...  def bits(self, reader):
>> ...   return BitSet()
>> ...
>> >>> f=MyFilter()
>> Traceback (most recent call last):
>>   File "<stdin>", line 1, in ?
>> pybackend.thirdparty.PyLucene.lnxpyd.PyLucene.InvalidArgsError: 
>> (<class '__main__.MyFilter'>, '__init__', ())
>>
>>
>> So, am I missing something, or is ConstantScoreQuery currently only 
>> capable of using built-in filters?
>>
>> I'm using PyLucene 2.1.0-1 on Gentoo Linux with gcc 4.1.2; all tests 
>> and sample code works for me.
>>
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>
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