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Posted to java-user@lucene.apache.org by Amrit Jassal <aj...@gmail.com> on 2006/02/10 00:02:50 UTC
Custom filters and booleanquery (MUST_NOT)
I am experimenting with using a custom filter with QueryParser and ran into
some unanticipated issues with using NOT terms. I narrowed down the issue
into the following test case. I am expecting a MUST_NOT booleanclause within
a booleanquery to return a resultset that is the complement of a MUST
clause. Can filters not be used for negative queries (such as "-term:xxx")
like this?
BTW I have checked with the latest SVN codebase as well.
Thanks for any hints...
=====
import java.io.IOException;
import java.util.BitSet;
import java.util.Iterator;
import org.apache.lucene.analysis.SimpleAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.Filter;
import org.apache.lucene.search.FilteredQuery;
import org.apache.lucene.search.Hit;
import org.apache.lucene.search.Hits;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.MatchAllDocsQuery;
import org.apache.lucene.store.RAMDirectory;
import junit.framework.TestCase;
public class FilteredQueryTest extends TestCase {
private class MyFilter extends Filter {
MyFilter(BitSet bits) {
this.bits= bits;
}
@Override
public BitSet bits(IndexReader arg0) throws IOException {
return this.bits;
}
private BitSet bits;
}
public void setUp() throws Exception {
RAMDirectory indexStore = new RAMDirectory ();
IndexWriter writer = new IndexWriter (indexStore, new
SimpleAnalyzer(), true);
Document doc = new Document();
doc.add(new Field("tag", "t1", Field.Store.YES,
Field.Index.UN_TOKENIZED));
writer.addDocument(doc);
doc = new Document();
doc.add(new Field("tag", "t2", Field.Store.YES,
Field.Index.UN_TOKENIZED));
writer.addDocument(doc);
writer.optimize ();
writer.close();
this.searcher = new IndexSearcher (indexStore);
}
public void testFilter() {
try {
BitSet bits = new BitSet(this.searcher.maxDoc());
bits.set(1);
FilteredQuery fq = new FilteredQuery(new MatchAllDocsQuery(),
new MyFilter(bits));
BooleanQuery bquery = new BooleanQuery();
bquery.add(new BooleanClause(fq, BooleanClause.Occur.MUST));
Hits hits = this.searcher.search(bquery);
assertTrue(hits.length() == 1);
for (Iterator h = hits.iterator(); h.hasNext(); ) {
assertTrue(((Hit)h.next()).getId() == 1);
}
bquery = new BooleanQuery();
bquery.add(new BooleanClause(fq, BooleanClause.Occur.MUST_NOT));
hits = this.searcher.search(bquery);
assertTrue(hits.length() == 1); // <<<<<<<<< returns 0,
expecting doc #2 (t2) to return...
for (Iterator h = hits.iterator(); h.hasNext(); ) {
assertTrue(((Hit)h.next()).getId() == 2);
}
} catch (Exception e) {
e.printStackTrace();
fail();
}
}
private IndexSearcher searcher;
}
Re: Custom filters and booleanquery (MUST_NOT)
Posted by Amrit Jassal <aj...@gmail.com>.
Chris
Thanks. Appreciate your comment about using ConstantScoreQuery as well.
Amrit
On 2/9/06, Chris Hostetter <ho...@fucit.org> wrote:
>
>
> : I am experimenting with using a custom filter with QueryParser and ran
> into
> : some unanticipated issues with using NOT terms. I narrowed down the
> issue
>
> ...
>
> : bquery = new BooleanQuery();
> : bquery.add(new BooleanClause(fq,
> BooleanClause.Occur.MUST_NOT));
> : hits = this.searcher.search(bquery);
> : assertTrue(hits.length() == 1); // <<<<<<<<< returns
> 0, expecting doc #2 (t2) to return...
>
> ...this isn't really a Filter issue at all, you're trying to execute a
> query that only contains prohibited (ie: MUST_NOT) clauses. Thus you are
> not positively selecting anything -- this is one of hte main use for
> MatchAllDocsQuery, try...
>
>
> bquery = new BooleanQuery();
> bquery.add(new BooleanClause(fq, BooleanClause.Occur.MUST_NOT));
> bquery.add(new BooleanClause(new MatchAllDocsQuery(),
> BooleanClause.Occur.MUST));
> hits = this.searcher.search(bquery);
> assertTrue(hits.length() == 1);
>
> ...incidently, if you are constructing a FilteredQuery arround a
> MatchAllDocsQuery, you might as well use a ConstantScoreQuery instead.
>
>
> -Hoss
>
>
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>
Re: Custom filters and booleanquery (MUST_NOT)
Posted by Chris Hostetter <ho...@fucit.org>.
: I am experimenting with using a custom filter with QueryParser and ran into
: some unanticipated issues with using NOT terms. I narrowed down the issue
...
: bquery = new BooleanQuery();
: bquery.add(new BooleanClause(fq, BooleanClause.Occur.MUST_NOT));
: hits = this.searcher.search(bquery);
: assertTrue(hits.length() == 1); // <<<<<<<<< returns 0, expecting doc #2 (t2) to return...
...this isn't really a Filter issue at all, you're trying to execute a
query that only contains prohibited (ie: MUST_NOT) clauses. Thus you are
not positively selecting anything -- this is one of hte main use for
MatchAllDocsQuery, try...
bquery = new BooleanQuery();
bquery.add(new BooleanClause(fq, BooleanClause.Occur.MUST_NOT));
bquery.add(new BooleanClause(new MatchAllDocsQuery(),
BooleanClause.Occur.MUST));
hits = this.searcher.search(bquery);
assertTrue(hits.length() == 1);
...incidently, if you are constructing a FilteredQuery arround a
MatchAllDocsQuery, you might as well use a ConstantScoreQuery instead.
-Hoss
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