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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.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.apache.lucene.search.Scorer;
import org.elasticsearch.script.CompiledScript;
import org.elasticsearch.script.GeneralScriptException;
import org.elasticsearch.script.LeafSearchScript;
import org.elasticsearch.script.SearchScript;
import java.io.IOException;
import java.util.Map;
/**
* A bridge to evaluate an {@link Expression} against {@link Bindings} in the context
* of a {@link SearchScript}.
*/
class ExpressionSearchScript implements SearchScript {
final CompiledScript compiledScript;
final SimpleBindings bindings;
final DoubleValuesSource source;
final ReplaceableConstDoubleValueSource specialValue; // _value
final boolean needsScores;
Scorer scorer;
int docid;
ExpressionSearchScript(CompiledScript c, SimpleBindings b, ReplaceableConstDoubleValueSource v, boolean needsScores) {
compiledScript = c;
bindings = b;
source = ((Expression)compiledScript.compiled()).getDoubleValuesSource(bindings);
specialValue = v;
this.needsScores = needsScores;
}
@Override
public boolean needsScores() {
return needsScores;
}
@Override
public LeafSearchScript getLeafSearchScript(final LeafReaderContext leaf) throws IOException {
return new LeafSearchScript() {
// Fake the scorer until setScorer is called.
DoubleValues values = source.getValues(leaf, new DoubleValues() {
@Override
public double doubleValue() throws IOException {
return Double.NaN;
}
@Override
public boolean advanceExact(int doc) throws IOException {
return true;
}
});
double evaluate() {
try {
return values.doubleValue();
} catch (Exception exception) {
throw new GeneralScriptException("Error evaluating " + compiledScript, exception);
}
}
@Override
public Object run() { return Double.valueOf(evaluate()); }
@Override
public long runAsLong() { return (long)evaluate(); }
@Override
public double runAsDouble() { return evaluate(); }
@Override
public void setDocument(int d) {
docid = d;
try {
values.advanceExact(d);
} catch (IOException e) {
throw new IllegalStateException("Can't advance to doc using " + compiledScript, e);
}
}
@Override
public void setScorer(Scorer s) {
scorer = s;
try {
// We have a new binding for the scorer so we need to reset the values
values = source.getValues(leaf, new DoubleValues() {
@Override
public double doubleValue() throws IOException {
return scorer.score();
}
@Override
public boolean advanceExact(int doc) throws IOException {
return true;
}
});
} catch (IOException e) {
throw new IllegalStateException("Can't get values using " + compiledScript, e);
}
}
@Override
public void setSource(Map<String, Object> source) {
// noop: expressions don't use source data
}
@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 " + compiledScript);
}
}
}
@Override
public void setNextVar(String name, Object value) {
// other per-document variables aren't supported yet, even if they are numbers
// but we shouldn't encourage this anyway.
}
};
}
}