Hi,
I was looking at SpanNotQuery to see if I could make do without the
position increment gaps. A search requirement that's causing me some
trouble to implement is when two terms are supposed to be on the same
L_2, yet on different L_3's (L_3's are hierarchically below L_2).
With the position increments in place, I can do this:
<SpanNot fieldName="MyField">
<Include>
<SpanNear slop="100000" inOrder="false">
<SpanTerm>t293</SpanTerm>
<SpanTerm>t4979</SpanTerm>
</SpanNear>
</Include>
<Exclude>
<SpanNear slop="1000" inOrder="false">
<SpanTerm>t293</SpanTerm>
<SpanTerm>t4979</SpanTerm>
</SpanNear>
</Exclude>
</SpanNot>
This query returns the expected documents.
I didn't manage to come up with a working solution for the approach
without posIncGaps. The following, I thought, should work, but for some
reason it doesn't:
<SpanNot fieldName="MyField">
<Include>
<!-- Gets all the matching spans within L_2 boundaries and includes them -->
<SpanNot>
<Include>
<SpanNear slop="2147483647" inOrder="false" >
<SpanTerm>t293</SpanTerm>
<SpanTerm>t4979</SpanTerm>
</SpanNear>
</Include>
<Exclude>
<SpanTerm>L_2</SpanTerm>
</Exclude>
</SpanNot>
</Include>
<Exclude>
<!-- Gets all the matching spans from L_3 boundaries and excludes them -->
<SpanNot>
<Include>
<SpanNear slop="2147483647" inOrder="false" >
<SpanTerm>t293</SpanTerm>
<SpanTerm>t4979</SpanTerm>
</SpanNear>
</Include>
<Exclude>
<SpanTerm>L_3</SpanTerm>
</Exclude>
</SpanNot>
</Exclude>
</SpanNot>
Shouldn't this query only leave documents, where t293 and t4979 are in
the same L_2, but not within the same L_3? I fiddled about with
different queries to no avail and I feel the above is the most
straightforward try. But the query doesn't match any document at all.
Any ideas on how to improve the second query would be greatly appreciated.
Thanks
Rene
Hi Rene,
Have you seen SpanNotQuery?:
<http://lucene.apache.org/java/3_0_1/api/core/org/apache/lucene/search/spans/SpanNotQuery.html>
For a document that looks like:
<Level_1 id="1">
<Level_2 id="1">
<Level_3 id="1">T1 T2 T3</Level_3>
<Level_3 id="2">T4 T5 T6</Level_3>
<Level_3 id="3">T7 T8 T9</Level_3>
</Level_2>
<Level_2 id="2">
<Level_3 id="1">T10 T11 T12</Level_3>
<Level_3 id="2">T13 T14 T15</Level_3>
<Level_3 id="3">T16 T17 T18</Level_3>
</Level_2>
...
</Level1>
...
You could generate the following token stream (L_X being a concrete level
boundary token):
L_1 L_2 L_3 T1 T2 T3 L_3 T4 T5 T6 L_3 T7 T8 T9
L_2 L_3 T10 T11 T12 L_3 T13 T14 T15 L_3 T16 T17 T18
L_2 ...
...
A query to find T2 and T8 on the same Level_2 would require you to find a span
containing T2 and T8, but not containing L_2.
This scheme will generalize to as many levels as you need, and you can use
nested span queries to simultaneously provide constraints at multiple levels.
No position increment gap required.
Caveat: this scheme is not tested - I could be way off base :).
Steve
---------------------------------------------------------------------
To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org
For additional commands, e-mail: java-user-h...@lucene.apache.org
