Make sure to setRewriteMethod on the MultiTermQuery to:
MultiTermQuery.SCORING_BOOLEAN_REWRITE or CONSTANT_SCORE_BOOLEAN_REWRITE
Then something like this should work:
q = q.rewrite(reader);
Set<Term> terms = new HashSet<>();
Weight weight = q.createWeight(searcher, false);
weight.extractTerms(terms);
-----Original Message-----
From: Evert Wagenaar [mailto:evert.wagen...@gmail.com]
Sent: Monday, October 24, 2016 12:41 PM
To: java-user@lucene.apache.org
Subject: How to get the terms matching a WildCardQuery in Lucene 6.2?
I already asked this on StackOverflow. Unfortunately without any answer for
over a week now.
Therefore again to the real experts:
I downloaded a list of 350.000 English words in a .txt file and Indexed it
using the latest Lucene (6.2). I want to apply wildcard queries like aard????
and then retreive a list of matches.
I've done this before in an older version of Lucene. Here it was pretty simple.
I just had to do a Query.rewrite() and this retuned what I needed.
Unfortunately in 6.2 this doesn't work anymore. There is a
Query.rewrite(Indexreader reader) which should return a HashMap of Terms.
In my case there's only one matching Term (aardvark). The Searcher returns one
hit, containing the Document path to the wordlist. The HashMap is however empty.
When I change the Query to find more then one single match (like aa*) the
HashMap remains empty.
I tried the MatchExtractor too. Unfortunately without result.
The Objective of this is to demonstrate the power of Lucene to easily find
words of a particular length, given one or more characters. I'm pretty sure I
can do this using regular expressions in Java but then it's outside my
objective.
Can anyone tell me why this isn't working? I use the StandardAnalyzer.
Should I use a different Application?
Any help is greatly appreciated.
Thanks.
--
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