| /* |
| * 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.java.operators; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Optional; |
| import java.util.Set; |
| import java.util.function.BiConsumer; |
| import java.util.function.BinaryOperator; |
| import java.util.function.Function; |
| import java.util.function.Supplier; |
| import java.util.stream.Collector; |
| import java.util.stream.Collectors; |
| import org.apache.wayang.basic.operators.ReduceByOperator; |
| import org.apache.wayang.core.api.Configuration; |
| import org.apache.wayang.core.function.ReduceDescriptor; |
| import org.apache.wayang.core.function.TransformationDescriptor; |
| import org.apache.wayang.core.optimizer.OptimizationContext; |
| import org.apache.wayang.core.optimizer.costs.LoadProfileEstimator; |
| import org.apache.wayang.core.optimizer.costs.LoadProfileEstimators; |
| import org.apache.wayang.core.plan.wayangplan.ExecutionOperator; |
| import org.apache.wayang.core.platform.ChannelDescriptor; |
| import org.apache.wayang.core.platform.ChannelInstance; |
| import org.apache.wayang.core.platform.lineage.ExecutionLineageNode; |
| import org.apache.wayang.core.types.DataSetType; |
| import org.apache.wayang.core.util.Tuple; |
| import org.apache.wayang.java.channels.CollectionChannel; |
| import org.apache.wayang.java.channels.JavaChannelInstance; |
| import org.apache.wayang.java.channels.StreamChannel; |
| import org.apache.wayang.java.execution.JavaExecutor; |
| |
| /** |
| * Java implementation of the {@link ReduceByOperator}. |
| */ |
| public class JavaReduceByOperator<Type, KeyType> |
| extends ReduceByOperator<Type, KeyType> |
| implements JavaExecutionOperator { |
| |
| |
| /** |
| * Creates a new instance. |
| * |
| * @param type type of the reduce elements (i.e., type of {@link #getInput()} and {@link #getOutput()}) |
| * @param keyDescriptor describes how to extract the key from data units |
| * @param reduceDescriptor describes the reduction to be performed on the elements |
| */ |
| public JavaReduceByOperator(DataSetType<Type> type, TransformationDescriptor<Type, KeyType> keyDescriptor, |
| ReduceDescriptor<Type> reduceDescriptor) { |
| super(keyDescriptor, reduceDescriptor, type); |
| } |
| |
| /** |
| * Copies an instance (exclusive of broadcasts). |
| * |
| * @param that that should be copied |
| */ |
| public JavaReduceByOperator(ReduceByOperator<Type, KeyType> that) { |
| super(that); |
| } |
| |
| @Override |
| public Tuple<Collection<ExecutionLineageNode>, Collection<ChannelInstance>> evaluate( |
| ChannelInstance[] inputs, |
| ChannelInstance[] outputs, |
| JavaExecutor javaExecutor, |
| OptimizationContext.OperatorContext operatorContext) { |
| assert inputs.length == this.getNumInputs(); |
| assert outputs.length == this.getNumOutputs(); |
| |
| final Function<Type, KeyType> keyExtractor = javaExecutor.getCompiler().compile(this.keyDescriptor); |
| final BinaryOperator<Type> reduceFunction = javaExecutor.getCompiler().compile(this.reduceDescriptor); |
| JavaExecutor.openFunction(this, reduceFunction, inputs, operatorContext); |
| |
| final Map<KeyType, Type> reductionResult = ((JavaChannelInstance) inputs[0]).<Type>provideStream().collect( |
| Collectors.groupingBy(keyExtractor, new ReducingCollector<>(reduceFunction)) |
| ); |
| ((CollectionChannel.Instance) outputs[0]).accept(reductionResult.values()); |
| |
| return ExecutionOperator.modelEagerExecution(inputs, outputs, operatorContext); |
| } |
| |
| @Override |
| public String getLoadProfileEstimatorConfigurationKey() { |
| return "wayang.java.reduceby.load"; |
| } |
| |
| @Override |
| public Optional<LoadProfileEstimator> createLoadProfileEstimator(Configuration configuration) { |
| final Optional<LoadProfileEstimator> optEstimator = |
| JavaExecutionOperator.super.createLoadProfileEstimator(configuration); |
| LoadProfileEstimators.nestUdfEstimator(optEstimator, this.keyDescriptor, configuration); |
| LoadProfileEstimators.nestUdfEstimator(optEstimator, this.reduceDescriptor, configuration); |
| return optEstimator; |
| } |
| |
| @Override |
| protected ExecutionOperator createCopy() { |
| return new JavaReduceByOperator<>(this.getType(), this.getKeyDescriptor(), this.getReduceDescriptor()); |
| } |
| |
| @Override |
| public List<ChannelDescriptor> getSupportedInputChannels(int index) { |
| assert index <= this.getNumInputs() || (index == 0 && this.getNumInputs() == 0); |
| if (this.getInput(index).isBroadcast()) return Collections.singletonList(CollectionChannel.DESCRIPTOR); |
| return Arrays.asList(CollectionChannel.DESCRIPTOR, StreamChannel.DESCRIPTOR); |
| } |
| |
| @Override |
| public List<ChannelDescriptor> getSupportedOutputChannels(int index) { |
| assert index <= this.getNumOutputs() || (index == 0 && this.getNumOutputs() == 0); |
| return Collections.singletonList(CollectionChannel.DESCRIPTOR); |
| } |
| |
| /** |
| * Immitates {@link Collectors#reducing(BinaryOperator)} but assumes that there is always at least one element |
| * in each reduction. |
| */ |
| private static class ReducingCollector<T> implements Collector<T, List<T>, T> { |
| |
| private final BinaryOperator<T> reduceFunction; |
| |
| ReducingCollector(BinaryOperator<T> reduceFunction) { |
| this.reduceFunction = reduceFunction; |
| } |
| |
| @Override |
| public Supplier<List<T>> supplier() { |
| return () -> new ArrayList<>(1); |
| } |
| |
| @Override |
| public BiConsumer<List<T>, T> accumulator() { |
| return (list, element) -> { |
| if (list.isEmpty()) { |
| list.add(element); |
| } else { |
| list.set(0, this.reduceFunction.apply(list.get(0), element)); |
| } |
| }; |
| } |
| |
| @Override |
| public BinaryOperator<List<T>> combiner() { |
| return (list1, list2) -> { |
| if (list1.isEmpty()) { |
| return list2; |
| } else if (list2.isEmpty()) { |
| return list2; |
| } else { |
| list1.set(0, this.reduceFunction.apply(list1.get(0), list2.get(0))); |
| return list1; |
| } |
| }; |
| } |
| |
| @Override |
| public Function<List<T>, T> finisher() { |
| return list -> { |
| assert !list.isEmpty(); |
| return list.get(0); |
| }; |
| } |
| |
| @Override |
| public Set<Characteristics> characteristics() { |
| return Collections.emptySet(); |
| } |
| } |
| } |