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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.script;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.Scorable;
import org.elasticsearch.Version;
import org.elasticsearch.index.fielddata.ScriptDocValues;
import org.elasticsearch.search.lookup.LeafSearchLookup;
import org.elasticsearch.search.lookup.SearchLookup;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.function.DoubleSupplier;
/**
* A script used for adjusting the score on a per document basis.
*/
public abstract class ScoreScript {
/** A helper to take in an explanation from a script and turn it into an {@link org.apache.lucene.search.Explanation} */
public static class ExplanationHolder {
private String description;
/**
* Explain the current score.
*
* @param description A textual description of how the score was calculated
*/
public void set(String description) {
this.description = description;
}
public Explanation get(double score, Explanation subQueryExplanation) {
if (description == null) {
return null;
}
if (subQueryExplanation != null) {
return Explanation.match(score, description, subQueryExplanation);
}
return Explanation.match(score, description);
}
}
private static final Map DEPRECATIONS;
static {
Map deprecations = new HashMap<>();
deprecations.put(
"doc",
"Accessing variable [doc] via [params.doc] from within a score script " +
"is deprecated in favor of directly accessing [doc]."
);
deprecations.put(
"_doc",
"Accessing variable [doc] via [params._doc] from within a score script " +
"is deprecated in favor of directly accessing [doc]."
);
DEPRECATIONS = Collections.unmodifiableMap(deprecations);
}
public static final String[] PARAMETERS = new String[]{ "explanation" };
/** The generic runtime parameters for the script. */
private final Map params;
/** A leaf lookup for the bound segment this script will operate on. */
private final LeafSearchLookup leafLookup;
private DoubleSupplier scoreSupplier = () -> 0.0;
private final int docBase;
private int docId;
private int shardId = -1;
private String indexName = null;
private Version indexVersion = null;
public ScoreScript(Map params, SearchLookup lookup, LeafReaderContext leafContext) {
// null check needed b/c of expression engine subclass
if (lookup == null) {
assert params == null;
assert leafContext == null;
this.params = null;
this.leafLookup = null;
this.docBase = 0;
} else {
this.leafLookup = lookup.getLeafSearchLookup(leafContext);
params = new HashMap<>(params);
params.putAll(leafLookup.asMap());
this.params = new DeprecationMap(params, DEPRECATIONS, "score-script");
this.docBase = leafContext.docBase;
}
}
public abstract double execute(ExplanationHolder explanation);
/** Return the parameters for this script. */
public Map getParams() {
return params;
}
/** The doc lookup for the Lucene segment this script was created for. */
public Map> getDoc() {
return leafLookup.doc();
}
/** Set the current document to run the script on next. */
public void setDocument(int docid) {
this.docId = docid;
leafLookup.setDocument(docid);
}
public void setScorer(Scorable scorer) {
this.scoreSupplier = () -> {
try {
return scorer.score();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
};
}
/**
* Accessed as _score in the painless script
* @return the score of the inner query
*/
public double get_score() {
return scoreSupplier.getAsDouble();
}
/**
* Starting a name with underscore, so that the user cannot access this function directly through a script
* It is only used within predefined painless functions.
* @return the internal document ID
*/
public int _getDocId() {
return docId;
}
/**
* Starting a name with underscore, so that the user cannot access this function directly through a script
* It is only used within predefined painless functions.
* @return the internal document ID with the base
*/
public int _getDocBaseId() {
return docBase + docId;
}
/**
* Starting a name with underscore, so that the user cannot access this function directly through a script
* It is only used within predefined painless functions.
* @return shard id or throws an exception if shard is not set up for this script instance
*/
public int _getShardId() {
if (shardId > -1) {
return shardId;
} else {
throw new IllegalArgumentException("shard id can not be looked up!");
}
}
/**
* Starting a name with underscore, so that the user cannot access this function directly through a script
* It is only used within predefined painless functions.
* @return index name or throws an exception if the index name is not set up for this script instance
*/
public String _getIndex() {
if (indexName != null) {
return indexName;
} else {
throw new IllegalArgumentException("index name can not be looked up!");
}
}
/**
* Starting a name with underscore, so that the user cannot access this function directly through a script
* It is only used within predefined painless functions.
* @return index version or throws an exception if the index version is not set up for this script instance
*/
public Version _getIndexVersion() {
if (indexVersion != null) {
return indexVersion;
} else {
throw new IllegalArgumentException("index version can not be looked up!");
}
}
/**
* Starting a name with underscore, so that the user cannot access this function directly through a script
*/
public void _setShard(int shardId) {
this.shardId = shardId;
}
/**
* Starting a name with underscore, so that the user cannot access this function directly through a script
*/
public void _setIndexName(String indexName) {
this.indexName = indexName;
}
/**
* Starting a name with underscore, so that the user cannot access this function directly through a script
*/
public void _setIndexVersion(Version indexVersion) {
this.indexVersion = indexVersion;
}
/** A factory to construct {@link ScoreScript} instances. */
public interface LeafFactory {
/**
* Return {@code true} if the script needs {@code _score} calculated, or {@code false} otherwise.
*/
boolean needs_score();
ScoreScript newInstance(LeafReaderContext ctx) throws IOException;
}
/** A factory to construct stateful {@link ScoreScript} factories for a specific index. */
public interface Factory extends ScriptFactory {
ScoreScript.LeafFactory newFactory(Map params, SearchLookup lookup);
}
public static final ScriptContext CONTEXT = new ScriptContext<>("score", ScoreScript.Factory.class);
}