org.elasticsearch.index.query.BoostingQueryBuilder Maven / Gradle / Ivy
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* the Apache License, Version 2.0 (the "License"); you may
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* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
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*/
package org.elasticsearch.index.query;
import org.elasticsearch.ElasticsearchIllegalArgumentException;
import org.elasticsearch.common.xcontent.XContentBuilder;
import java.io.IOException;
/**
* The BoostingQuery class can be used to effectively demote results that match a given query.
* Unlike the "NOT" clause, this still selects documents that contain undesirable terms,
* but reduces their overall score:
*
* Query balancedQuery = new BoostingQuery(positiveQuery, negativeQuery, 0.01f);
* In this scenario the positiveQuery contains the mandatory, desirable criteria which is used to
* select all matching documents, and the negativeQuery contains the undesirable elements which
* are simply used to lessen the scores. Documents that match the negativeQuery have their score
* multiplied by the supplied "boost" parameter, so this should be less than 1 to achieve a
* demoting effect
*/
public class BoostingQueryBuilder extends BaseQueryBuilder implements BoostableQueryBuilder {
private QueryBuilder positiveQuery;
private QueryBuilder negativeQuery;
private float negativeBoost = -1;
private float boost = -1;
public BoostingQueryBuilder() {
}
public BoostingQueryBuilder positive(QueryBuilder positiveQuery) {
this.positiveQuery = positiveQuery;
return this;
}
public BoostingQueryBuilder negative(QueryBuilder negativeQuery) {
this.negativeQuery = negativeQuery;
return this;
}
public BoostingQueryBuilder negativeBoost(float negativeBoost) {
this.negativeBoost = negativeBoost;
return this;
}
public BoostingQueryBuilder boost(float boost) {
this.boost = boost;
return this;
}
@Override
protected void doXContent(XContentBuilder builder, Params params) throws IOException {
if (positiveQuery == null) {
throw new ElasticsearchIllegalArgumentException("boosting query requires positive query to be set");
}
if (negativeQuery == null) {
throw new ElasticsearchIllegalArgumentException("boosting query requires negative query to be set");
}
if (negativeBoost == -1) {
throw new ElasticsearchIllegalArgumentException("boosting query requires negativeBoost to be set");
}
builder.startObject(BoostingQueryParser.NAME);
builder.field("positive");
positiveQuery.toXContent(builder, params);
builder.field("negative");
negativeQuery.toXContent(builder, params);
builder.field("negative_boost", negativeBoost);
if (boost != -1) {
builder.field("boost", boost);
}
builder.endObject();
}
}