| /* |
| * 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 org.apache.wayang.basic.operators.SampleOperator; |
| import org.apache.wayang.core.function.FunctionDescriptor; |
| import org.apache.wayang.core.optimizer.OptimizationContext; |
| 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; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Random; |
| import java.util.function.IntUnaryOperator; |
| import java.util.function.LongUnaryOperator; |
| import java.util.stream.Collectors; |
| |
| /** |
| * Java implementation of the {@link JavaReservoirSampleOperator}. |
| */ |
| public class JavaReservoirSampleOperator<Type> |
| extends SampleOperator<Type> |
| implements JavaExecutionOperator { |
| |
| private Random rand; |
| |
| /** |
| * Creates a new instance. |
| */ |
| public JavaReservoirSampleOperator(FunctionDescriptor.SerializableIntUnaryOperator sampleSizeFunction, DataSetType<Type> type, FunctionDescriptor.SerializableLongUnaryOperator seed) { |
| super(sampleSizeFunction, type, Methods.RESERVOIR, seed); |
| } |
| |
| /** |
| * Copies an instance (exclusive of broadcasts). |
| * |
| * @param that that should be copied |
| */ |
| public JavaReservoirSampleOperator(SampleOperator<Type> that) { |
| super(that); |
| assert that.getSampleMethod() == Methods.RESERVOIR || that.getSampleMethod() == Methods.ANY; |
| } |
| |
| @Override |
| @SuppressWarnings("unchecked") |
| 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(); |
| |
| int sampleSize = this.getSampleSize(operatorContext); |
| |
| if (sampleSize >= datasetSize) { //return all |
| ((CollectionChannel.Instance) outputs[0]).accept(((JavaChannelInstance) inputs[0]).provideStream().collect(Collectors.toList())); |
| } |
| else { |
| long seed = this.getSeed(operatorContext); |
| rand = new Random(seed); |
| |
| ((CollectionChannel.Instance) outputs[0]).accept(reservoirSample(rand, ((JavaChannelInstance) inputs[0]).<Type>provideStream().iterator(), sampleSize)); |
| } |
| return ExecutionOperator.modelEagerExecution(inputs, outputs, operatorContext); |
| } |
| |
| private static <T> List<T> reservoirSample(Random rand, Iterator<T> items, long m) { |
| ArrayList<T> res = new ArrayList<T>(Math.toIntExact(m)); |
| int count = 0; |
| while (items.hasNext()) { |
| T item = items.next(); |
| count++; |
| if (count <= m) |
| res.add(item); |
| else { |
| int r = rand.nextInt(count); |
| if (r < m) |
| res.set(r, item); |
| } |
| } |
| return res; |
| } |
| |
| @Override |
| public Collection<String> getLoadProfileEstimatorConfigurationKeys() { |
| return Collections.singleton("wayang.java.reservoir-sample.load"); |
| } |
| |
| @Override |
| protected ExecutionOperator createCopy() { |
| return new JavaReservoirSampleOperator<>(this); |
| } |
| |
| @Override |
| public List<ChannelDescriptor> getSupportedInputChannels(int index) { |
| assert index <= this.getNumInputs() || (index == 0 && this.getNumInputs() == 0); |
| 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); |
| } |
| |
| } |