org.elasticsearch.script.AggregationScript Maven / Gradle / Ivy
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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 java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.Scorable;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.common.lucene.ScorerAware;
import org.elasticsearch.index.fielddata.ScriptDocValues;
import org.elasticsearch.search.lookup.LeafSearchLookup;
import org.elasticsearch.search.lookup.SearchLookup;
public abstract class AggregationScript implements ScorerAware {
public static final String[] PARAMETERS = {};
public static final ScriptContext CONTEXT = new ScriptContext<>("aggs", Factory.class);
private static final Map DEPRECATIONS;
static {
Map deprecations = new HashMap<>();
deprecations.put(
"doc",
"Accessing variable [doc] via [params.doc] from within an aggregation-script " +
"is deprecated in favor of directly accessing [doc]."
);
deprecations.put(
"_doc",
"Accessing variable [doc] via [params._doc] from within an aggregation-script " +
"is deprecated in favor of directly accessing [doc]."
);
DEPRECATIONS = Collections.unmodifiableMap(deprecations);
}
/**
* 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;
/**
* A scorer that will return the score for the current document when the script is run.
*/
protected Scorable scorer;
private Object value;
public AggregationScript(Map params, SearchLookup lookup, LeafReaderContext leafContext) {
this.params = new DeprecationMap(new HashMap<>(params), DEPRECATIONS, "aggregation-script");
this.leafLookup = lookup.getLeafSearchLookup(leafContext);
this.params.putAll(leafLookup.asMap());
}
protected AggregationScript() {
params = null;
leafLookup = null;
}
/**
* 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) {
leafLookup.setDocument(docid);
}
@Override
public void setScorer(Scorable scorer) {
this.scorer = scorer;
}
/**
* Sets per-document aggregation {@code _value}.
*
* The default implementation just calls {@code setNextVar("_value", value)} but
* some engines might want to handle this differently for better performance.
*
* @param value per-document value, typically a String, Long, or Double
*/
public void setNextAggregationValue(Object value) {
this.value = value;
}
public Number get_score() {
try {
return scorer == null ? 0.0 : scorer.score();
} catch (IOException e) {
throw new ElasticsearchException("couldn't lookup score", e);
}
}
public Object get_value() {
return value;
}
/**
* Return the result as a long. This is used by aggregation scripts over long fields.
*/
public long runAsLong() {
return ((Number) execute()).longValue();
}
public double runAsDouble() {
return ((Number) execute()).doubleValue();
}
public abstract Object execute();
/**
* A factory to construct {@link AggregationScript} instances.
*/
public interface LeafFactory {
AggregationScript newInstance(LeafReaderContext ctx) throws IOException;
/**
* Return {@code true} if the script needs {@code _score} calculated, or {@code false} otherwise.
*/
boolean needs_score();
}
/**
* A factory to construct stateful {@link AggregationScript} factories for a specific index.
*/
public interface Factory extends ScriptFactory {
LeafFactory newFactory(Map params, SearchLookup lookup);
}
}