| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF 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.apache.wayang.basic.mapping; |
| |
| import java.util.Collection; |
| import java.util.Collections; |
| import org.apache.wayang.basic.operators.GroupByOperator; |
| import org.apache.wayang.basic.operators.ReduceByOperator; |
| import org.apache.wayang.basic.operators.ReduceOperator; |
| import org.apache.wayang.core.mapping.Mapping; |
| import org.apache.wayang.core.mapping.OperatorPattern; |
| import org.apache.wayang.core.mapping.PlanTransformation; |
| import org.apache.wayang.core.mapping.ReplacementSubplanFactory; |
| import org.apache.wayang.core.mapping.SubplanMatch; |
| import org.apache.wayang.core.mapping.SubplanPattern; |
| import org.apache.wayang.core.plan.wayangplan.Operator; |
| import org.apache.wayang.core.types.DataSetType; |
| |
| /** |
| * This mapping detects combinations of the {@link GroupByOperator} and {@link ReduceOperator} and merges them into |
| * a single {@link ReduceByOperator}. |
| */ |
| public class ReduceByMapping implements Mapping { |
| |
| |
| @Override |
| public Collection<PlanTransformation> getTransformations() { |
| return Collections.singleton(new PlanTransformation(this.createSubplanPattern(), new ReplacementFactory())); |
| } |
| |
| @SuppressWarnings("unchecked") |
| private SubplanPattern createSubplanPattern() { |
| final OperatorPattern groupByPattern = new OperatorPattern( |
| "groupBy", |
| new GroupByOperator<>( |
| null, |
| DataSetType.none(), |
| DataSetType.groupedNone() |
| ), |
| false); |
| final OperatorPattern reducePattern = new OperatorPattern( |
| "reduce", |
| ReduceOperator.createGroupedReduce( |
| null, |
| DataSetType.groupedNone(), |
| DataSetType.none() |
| ), |
| false); |
| groupByPattern.connectTo(0, reducePattern, 0); |
| return SubplanPattern.fromOperatorPatterns(groupByPattern, reducePattern); |
| } |
| |
| private static class ReplacementFactory extends ReplacementSubplanFactory { |
| |
| @Override |
| @SuppressWarnings("unchecked") |
| protected Operator translate(SubplanMatch subplanMatch, int epoch) { |
| final GroupByOperator groupBy = (GroupByOperator) subplanMatch.getMatch("groupBy").getOperator(); |
| final ReduceOperator reduce = (ReduceOperator) subplanMatch.getMatch("reduce").getOperator(); |
| |
| return new ReduceByOperator<>( |
| groupBy.getKeyDescriptor(), reduce.getReduceDescriptor(), groupBy.getInputType() |
| ).at(epoch); |
| } |
| } |
| |
| |
| } |