/*
* Licensed to Elastic Search and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Elastic Search 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.index.IndexReader;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.Query;
import org.elasticsearch.ElasticSearchIllegalStateException;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.lucene.search.function.FunctionScoreQuery;
import org.elasticsearch.common.lucene.search.function.ScoreFunction;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.script.SearchScript;
import org.elasticsearch.search.internal.SearchContext;
import java.io.IOException;
import java.util.Map;
/**
* @author kimchy (shay.banon)
*/
public class CustomScoreQueryParser implements QueryParser {
public static final String NAME = "custom_score";
@Inject public CustomScoreQueryParser() {
}
@Override public String[] names() {
return new String[]{NAME, Strings.toCamelCase(NAME)};
}
@Override public Query parse(QueryParseContext parseContext) throws IOException, QueryParsingException {
XContentParser parser = parseContext.parser();
Query query = null;
float boost = 1.0f;
String script = null;
String scriptLang = null;
Map<String, Object> vars = 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 ("query".equals(currentFieldName)) {
query = parseContext.parseInnerQuery();
} else if ("params".equals(currentFieldName)) {
vars = parser.map();
}
} else if (token.isValue()) {
if ("script".equals(currentFieldName)) {
script = parser.text();
} else if ("lang".equals(currentFieldName)) {
scriptLang = parser.text();
} else if ("boost".equals(currentFieldName)) {
boost = parser.floatValue();
}
}
}
if (query == null) {
throw new QueryParsingException(parseContext.index(), "[custom_score] requires 'query' field");
}
if (script == null) {
throw new QueryParsingException(parseContext.index(), "[custom_score] requires 'script' field");
}
SearchContext context = SearchContext.current();
if (context == null) {
throw new ElasticSearchIllegalStateException("No search context on going...");
}
SearchScript searchScript = context.scriptService().search(context.lookup(), scriptLang, script, vars);
FunctionScoreQuery functionScoreQuery = new FunctionScoreQuery(query, new ScriptScoreFunction(searchScript));
functionScoreQuery.setBoost(boost);
return functionScoreQuery;
}
public static class ScriptScoreFunction implements ScoreFunction {
private final SearchScript script;
public ScriptScoreFunction(SearchScript script) {
this.script = script;
}
@Override public void setNextReader(IndexReader reader) {
script.setNextReader(reader);
}
@Override public float score(int docId, float subQueryScore) {
script.setNextDocId(docId);
script.setNextScore(subQueryScore);
return script.runAsFloat();
}
@Override public Explanation explain(int docId, Explanation subQueryExpl) {
float score = score(docId, subQueryExpl.getValue());
Explanation exp = new Explanation(score, "script score function: product of:");
exp.addDetail(subQueryExpl);
return exp;
}
}
}