/*
* Hibernate Search, full-text search for your domain model
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later
* See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
*/
package org.hibernate.search.test.filter;
import java.io.IOException;
import java.io.Serializable;
import java.util.Set;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.Weight;
/**
* Apparently it's legal for Lucene weight to return a null scorer
* on {@link Weight#scorer(LeafReaderContext)} : make sure we can deal with it as well.
*
* @author Sanne Grinovero (C) 2011 Red Hat Inc.
*/
public class NullReturningEmptyFilter extends Query implements Serializable {
@Override
public Weight createWeight(IndexSearcher searcher, boolean needsScores) throws IOException {
return new NullReturningEmptyWeight( this );
}
@Override
public String toString(String field) {
return "";
}
public class NullReturningEmptyWeight extends Weight {
protected NullReturningEmptyWeight(Query query) {
super( query );
}
@Override
public void extractTerms(Set<Term> terms) {
// No-op
}
@Override
public Explanation explain(LeafReaderContext context, int doc) throws IOException {
return Explanation.noMatch( "Empty filter" );
}
@Override
public float getValueForNormalization() throws IOException {
return 0;
}
@Override
public void normalize(float norm, float boost) {
// No-op
}
@Override
public Scorer scorer(LeafReaderContext context) throws IOException {
return null;
}
}
}