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/*
* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* 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.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*/
package org.opensearch.script.expression;
import org.apache.lucene.expressions.Bindings;
import org.apache.lucene.expressions.Expression;
import org.apache.lucene.expressions.SimpleBindings;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.DoubleValues;
import org.apache.lucene.search.DoubleValuesSource;
import org.opensearch.script.AggregationScript;
import org.opensearch.script.GeneralScriptException;
import java.io.IOException;
/**
* A bridge to evaluate an {@link Expression} against {@link Bindings} in the context
* of a {@link AggregationScript}.
*/
class ExpressionAggregationScript implements AggregationScript.LeafFactory {
final Expression exprScript;
final SimpleBindings bindings;
final DoubleValuesSource source;
final boolean needsScore;
final PerThreadReplaceableConstDoubleValueSource specialValue; // _value
ExpressionAggregationScript(Expression e, SimpleBindings b, boolean n, PerThreadReplaceableConstDoubleValueSource v) {
exprScript = e;
bindings = b;
source = exprScript.getDoubleValuesSource(bindings);
needsScore = n;
specialValue = v;
}
@Override
public boolean needs_score() {
return needsScore;
}
@Override
public AggregationScript newInstance(final LeafReaderContext leaf) throws IOException {
return new AggregationScript() {
// Fake the scorer until setScorer is called.
DoubleValues values = source.getValues(leaf, new DoubleValues() {
@Override
public double doubleValue() throws IOException {
return get_score().doubleValue();
}
@Override
public boolean advanceExact(int doc) throws IOException {
return true;
}
});
@Override
public Object execute() {
try {
return values.doubleValue();
} catch (Exception exception) {
throw new GeneralScriptException("Error evaluating " + exprScript, exception);
}
}
@Override
public void setDocument(int d) {
try {
values.advanceExact(d);
} catch (IOException e) {
throw new IllegalStateException("Can't advance to doc using " + exprScript, e);
}
}
@Override
public void setNextAggregationValue(Object value) {
// _value isn't used in script if specialValue == null
if (specialValue != null) {
if (value instanceof Number) {
specialValue.setValue(((Number) value).doubleValue());
} else {
throw new GeneralScriptException("Cannot use expression with text variable using " + exprScript);
}
}
}
};
}
}