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/*
* 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;
import org.elasticsearch.common.ParsingException;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.lucene.search.function.ScoreFunction;
import org.elasticsearch.common.lucene.search.function.ScriptScoreFunction;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.index.query.QueryShardContext;
import org.elasticsearch.index.query.QueryShardException;
import org.elasticsearch.script.Script;
import org.elasticsearch.script.SearchScript;
import java.io.IOException;
import java.util.Objects;
/**
* A function that uses a script to compute or influence the score of documents
* that match with the inner query or filter.
*/
public class ScriptScoreFunctionBuilder extends ScoreFunctionBuilder {
public static final String NAME = "script_score";
private final Script script;
public ScriptScoreFunctionBuilder(Script script) {
if (script == null) {
throw new IllegalArgumentException("script must not be null");
}
this.script = script;
}
/**
* Read from a stream.
*/
public ScriptScoreFunctionBuilder(StreamInput in) throws IOException {
super(in);
script = new Script(in);
}
@Override
protected void doWriteTo(StreamOutput out) throws IOException {
script.writeTo(out);
}
public Script getScript() {
return this.script;
}
@Override
public void doXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject(getName());
builder.field(Script.SCRIPT_PARSE_FIELD.getPreferredName(), script);
builder.endObject();
}
@Override
public String getName() {
return NAME;
}
@Override
protected boolean doEquals(ScriptScoreFunctionBuilder functionBuilder) {
return Objects.equals(this.script, functionBuilder.script);
}
@Override
protected int doHashCode() {
return Objects.hash(this.script);
}
@Override
protected ScoreFunction doToFunction(QueryShardContext context) {
try {
SearchScript.Factory factory = context.getScriptService().compile(script, SearchScript.CONTEXT);
SearchScript.LeafFactory searchScript = factory.newFactory(script.getParams(), context.lookup());
return new ScriptScoreFunction(script, searchScript);
} catch (Exception e) {
throw new QueryShardException(context, "script_score: the script could not be loaded", e);
}
}
public static ScriptScoreFunctionBuilder fromXContent(XContentParser parser)
throws IOException, ParsingException {
Script script = 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 (Script.SCRIPT_PARSE_FIELD.match(currentFieldName)) {
script = Script.parse(parser);
} else {
throw new ParsingException(parser.getTokenLocation(), NAME + " query does not support [" + currentFieldName + "]");
}
}
}
if (script == null) {
throw new ParsingException(parser.getTokenLocation(), NAME + " requires 'script' field");
}
return new ScriptScoreFunctionBuilder(script);
}
}