| /* |
| * 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.operators; |
| |
| import org.apache.commons.lang3.Validate; |
| import org.apache.wayang.core.api.Configuration; |
| import org.apache.wayang.core.function.FunctionDescriptor; |
| import org.apache.wayang.core.function.MapPartitionsDescriptor; |
| import org.apache.wayang.core.optimizer.OptimizationContext; |
| import org.apache.wayang.core.optimizer.ProbabilisticDoubleInterval; |
| import org.apache.wayang.core.optimizer.cardinality.CardinalityEstimate; |
| import org.apache.wayang.core.plan.wayangplan.UnaryToUnaryOperator; |
| import org.apache.wayang.core.types.DataSetType; |
| |
| import java.util.Optional; |
| |
| /** |
| * This operator takes as input potentially multiple input data quanta and outputs multiple input data quanta. |
| * <p>Since Wayang is not a physical execution engine, its notion of partitions is rather loose. Implementors |
| * of this operator should guarantee that the partitions are distinct in their data quanta and that all partitions together |
| * are complete w.r.t. the data quanta.</p> |
| * <p>However, no further assumptions on partitions shall be made, such as: whether partitions can be iterated multiple |
| * times; whether partitions can be empty; whether there is a partition on each machine on distributed platforms; |
| * or whether partitions have a certain sorting order.</p> |
| */ |
| public class MapPartitionsOperator<InputType, OutputType> extends UnaryToUnaryOperator<InputType, OutputType> { |
| |
| /** |
| * Function that this operator applies to the input elements. |
| */ |
| protected final MapPartitionsDescriptor<InputType, OutputType> functionDescriptor; |
| |
| /** |
| * Creates a new instance. |
| */ |
| public MapPartitionsOperator(FunctionDescriptor.SerializableFunction<Iterable<InputType>, Iterable<OutputType>> function, |
| Class<InputType> inputTypeClass, |
| Class<OutputType> outputTypeClass) { |
| this(new MapPartitionsDescriptor<>(function, inputTypeClass, outputTypeClass)); |
| } |
| |
| /** |
| * Creates a new instance. |
| */ |
| public MapPartitionsOperator(MapPartitionsDescriptor<InputType, OutputType> functionDescriptor) { |
| this(functionDescriptor, |
| DataSetType.createDefault(functionDescriptor.getInputType()), |
| DataSetType.createDefault(functionDescriptor.getOutputType()) |
| ); |
| } |
| |
| /** |
| * Creates a new instance. |
| */ |
| public MapPartitionsOperator(MapPartitionsDescriptor<InputType, OutputType> functionDescriptor, |
| DataSetType<InputType> inputType, |
| DataSetType<OutputType> outputType) { |
| super(inputType, outputType, true); |
| this.functionDescriptor = functionDescriptor; |
| } |
| |
| /** |
| * Copies an instance (exclusive of broadcasts). |
| * |
| * @param that that should be copied |
| */ |
| public MapPartitionsOperator(MapPartitionsOperator<InputType, OutputType> that) { |
| super(that); |
| this.functionDescriptor = that.getFunctionDescriptor(); |
| } |
| |
| public MapPartitionsDescriptor<InputType, OutputType> getFunctionDescriptor() { |
| return this.functionDescriptor; |
| } |
| |
| @Override |
| public Optional<org.apache.wayang.core.optimizer.cardinality.CardinalityEstimator> createCardinalityEstimator( |
| final int outputIndex, |
| final Configuration configuration) { |
| Validate.inclusiveBetween(0, this.getNumOutputs() - 1, outputIndex); |
| return Optional.of(new MapPartitionsOperator.CardinalityEstimator(configuration)); |
| } |
| |
| /** |
| * Custom {@link org.apache.wayang.core.optimizer.cardinality.CardinalityEstimator} for {@link FlatMapOperator}s. |
| */ |
| private class CardinalityEstimator implements org.apache.wayang.core.optimizer.cardinality.CardinalityEstimator { |
| |
| /** |
| * The selectivity of this instance. |
| */ |
| private final ProbabilisticDoubleInterval selectivity; |
| |
| private CardinalityEstimator(Configuration configuration) { |
| this.selectivity = configuration |
| .getUdfSelectivityProvider() |
| .provideFor(MapPartitionsOperator.this.functionDescriptor); |
| } |
| |
| @Override |
| public CardinalityEstimate estimate(OptimizationContext optimizationContext, CardinalityEstimate... inputEstimates) { |
| assert MapPartitionsOperator.this.getNumInputs() == inputEstimates.length; |
| final CardinalityEstimate inputEstimate = inputEstimates[0]; |
| return new CardinalityEstimate( |
| (long) (inputEstimate.getLowerEstimate() * this.selectivity.getLowerEstimate()), |
| (long) (inputEstimate.getUpperEstimate() * this.selectivity.getUpperEstimate()), |
| inputEstimate.getCorrectnessProbability() * this.selectivity.getCorrectnessProbability() |
| ); |
| } |
| } |
| } |