/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* 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,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.index.query;
import org.apache.lucene.search.DisjunctionMaxQuery;
import org.apache.lucene.search.Query;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.xcontent.XContentParser;
import java.io.IOException;
import java.util.List;
import static com.google.common.collect.Lists.newArrayList;
/**
*
*/
public class DisMaxQueryParser implements QueryParser {
public static final String NAME = "dis_max";
@Inject
public DisMaxQueryParser() {
}
@Override
public String[] names() {
return new String[]{NAME, Strings.toCamelCase(NAME)};
}
@Override
public Query parse(QueryParseContext parseContext) throws IOException, QueryParsingException {
XContentParser parser = parseContext.parser();
float boost = 1.0f;
float tieBreaker = 0.0f;
List<Query> queries = newArrayList();
boolean queriesFound = false;
String queryName = null;
String currentFieldName = null;
XContentParser.Token token;
while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
if (token == XContentParser.Token.FIELD_NAME) {
currentFieldName = parser.currentName();
} else if (token == XContentParser.Token.START_OBJECT) {
if ("queries".equals(currentFieldName)) {
queriesFound = true;
Query query = parseContext.parseInnerQuery();
if (query != null) {
queries.add(query);
}
} else {
throw new QueryParsingException(parseContext.index(), "[dis_max] query does not support [" + currentFieldName + "]");
}
} else if (token == XContentParser.Token.START_ARRAY) {
if ("queries".equals(currentFieldName)) {
queriesFound = true;
while (token != XContentParser.Token.END_ARRAY) {
Query query = parseContext.parseInnerQuery();
if (query != null) {
queries.add(query);
}
token = parser.nextToken();
}
} else {
throw new QueryParsingException(parseContext.index(), "[dis_max] query does not support [" + currentFieldName + "]");
}
} else {
if ("boost".equals(currentFieldName)) {
boost = parser.floatValue();
} else if ("tie_breaker".equals(currentFieldName) || "tieBreaker".equals(currentFieldName)) {
tieBreaker = parser.floatValue();
} else if ("_name".equals(currentFieldName)) {
queryName = parser.text();
} else {
throw new QueryParsingException(parseContext.index(), "[dis_max] query does not support [" + currentFieldName + "]");
}
}
}
if (!queriesFound) {
throw new QueryParsingException(parseContext.index(), "[dis_max] requires 'queries' field");
}
if (queries.isEmpty()) {
return null;
}
DisjunctionMaxQuery query = new DisjunctionMaxQuery(queries, tieBreaker);
query.setBoost(boost);
if (queryName != null) {
parseContext.addNamedQuery(queryName, query);
}
return query;
}
}