algebricks/algebricks-rewriter/src/main/java/org/apache/hyracks/algebricks/rewriter/rules/IntroduceGroupByCombinerRule.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
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 * distributed with this work for additional information
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 * 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
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package org.apache.hyracks.algebricks.rewriter.rules;

import java.util.List;

import org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext;
import org.apache.hyracks.algebricks.core.algebra.base.LogicalVariable;
import org.apache.hyracks.algebricks.core.algebra.operators.logical.GroupByOperator;

public class IntroduceGroupByCombinerRule extends AbstractIntroduceGroupByCombinerRule {

    @Override
    protected void processNullTest(IOptimizationContext context, GroupByOperator nestedGby,
            List<LogicalVariable> aggregateVarsProducedByCombiner) {
        /** The default introduce group-by combiner rule ignores null test, however a language implementor can decide their own semantics. */
    }

}