org.elasticsearch.index.query.functionscore.random.RandomScoreFunctionParser Maven / Gradle / Ivy
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* the Apache License, Version 2.0 (the "License"); you may
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
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package org.elasticsearch.index.query.functionscore.random;
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.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 {
long 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)) {
seed = parser.longValue();
} else {
throw new QueryParsingException(parseContext.index(), NAMES[0] + " query does not support [" + currentFieldName + "]");
}
}
}
if (seed == -1) {
seed = parseContext.nowInMillis();
}
ShardId shardId = SearchContext.current().indexShard().shardId();
seed = salt(seed, shardId.index().name(), shardId.id());
return new RandomScoreFunction(seed);
}
public static long salt(long seed, String index, int shardId) {
long salt = index.hashCode();
salt = salt << 32;
salt |= shardId;
return salt^seed;
}
}