/*
* 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.functionscore.random;
import com.google.common.primitives.Longs;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.lucene.search.function.RandomScoreFunction;
import org.elasticsearch.common.lucene.search.function.ScoreFunction;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.fielddata.IndexFieldData;
import org.elasticsearch.index.mapper.FieldMapper;
import org.elasticsearch.index.query.QueryParseContext;
import org.elasticsearch.index.query.QueryParsingException;
import org.elasticsearch.index.query.functionscore.ScoreFunctionParser;
import org.elasticsearch.index.shard.ShardId;
import org.elasticsearch.search.internal.SearchContext;
import java.io.IOException;
public class RandomScoreFunctionParser implements ScoreFunctionParser {
public static String[] NAMES = { "random_score", "randomScore" };
@Inject
public RandomScoreFunctionParser() {
}
@Override
public String[] getNames() {
return NAMES;
}
@Override
public ScoreFunction parse(QueryParseContext parseContext, XContentParser parser) throws IOException, QueryParsingException {
int seed = -1;
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.isValue()) {
if ("seed".equals(currentFieldName)) {
if (token == XContentParser.Token.VALUE_NUMBER) {
if (parser.numberType() == XContentParser.NumberType.INT) {
seed = parser.intValue();
} else if (parser.numberType() == XContentParser.NumberType.LONG) {
seed = Longs.hashCode(parser.longValue());
} else {
throw new QueryParsingException(parseContext.index(), "random_score seed must be an int, long or string, not '" + token.toString() + "'");
}
} else if (token == XContentParser.Token.VALUE_STRING) {
seed = parser.text().hashCode();
} else {
throw new QueryParsingException(parseContext.index(), "random_score seed must be an int/long or string, not '" + token.toString() + "'");
}
} else {
throw new QueryParsingException(parseContext.index(), NAMES[0] + " query does not support [" + currentFieldName + "]");
}
}
}
final FieldMapper<?> mapper = SearchContext.current().mapperService().smartNameFieldMapper("_uid");
if (mapper == null) {
// mapper could be null if we are on a shard with no docs yet, so this won't actually be used
return new RandomScoreFunction();
}
if (seed == -1) {
seed = Longs.hashCode(parseContext.nowInMillis());
}
final ShardId shardId = SearchContext.current().indexShard().shardId();
final int salt = (shardId.index().name().hashCode() << 10) | shardId.id();
final IndexFieldData<?> uidFieldData = SearchContext.current().fieldData().getForField(mapper);
return new RandomScoreFunction(seed, salt, uidFieldData);
}
}