| /* |
| * 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.basic.data.Record; |
| import org.apache.wayang.basic.function.ProjectionDescriptor; |
| import org.apache.wayang.basic.types.RecordType; |
| import org.apache.wayang.core.api.Configuration; |
| import org.apache.wayang.core.function.FunctionDescriptor; |
| import org.apache.wayang.core.function.TransformationDescriptor; |
| import org.apache.wayang.core.optimizer.cardinality.CardinalityEstimator; |
| import org.apache.wayang.core.optimizer.cardinality.DefaultCardinalityEstimator; |
| import org.apache.wayang.core.plan.wayangplan.UnaryToUnaryOperator; |
| import org.apache.wayang.core.types.DataSetType; |
| |
| import java.util.Optional; |
| |
| /** |
| * A map operator represents semantics as they are known from frameworks, such as Spark and Flink. It pulls each |
| * available element from the input slot, applies a function to it, and pushes that element to the output slot. |
| */ |
| public class MapOperator<InputType, OutputType> extends UnaryToUnaryOperator<InputType, OutputType> { |
| |
| /** |
| * Function that this operator applies to the input elements. |
| */ |
| protected final TransformationDescriptor<InputType, OutputType> functionDescriptor; |
| |
| /** |
| * Creates a new instance. |
| */ |
| public MapOperator(FunctionDescriptor.SerializableFunction<InputType, OutputType> function, |
| Class<InputType> inputTypeClass, |
| Class<OutputType> outputTypeClass) { |
| this(new TransformationDescriptor<>(function, inputTypeClass, outputTypeClass)); |
| } |
| |
| /** |
| * Creates a new instance. |
| */ |
| public MapOperator(TransformationDescriptor<InputType, OutputType> functionDescriptor) { |
| this(functionDescriptor, |
| DataSetType.createDefault(functionDescriptor.getInputType()), |
| DataSetType.createDefault(functionDescriptor.getOutputType())); |
| } |
| |
| /** |
| * Creates a new instance. |
| */ |
| public MapOperator(TransformationDescriptor<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 MapOperator(MapOperator<InputType, OutputType> that) { |
| super(that); |
| this.functionDescriptor = that.getFunctionDescriptor(); |
| } |
| |
| /** |
| * Creates a new instance that projects the given fields. |
| * |
| * @param fieldNames the field names for the projected fields |
| * @return the new instance |
| */ |
| public static <Input, Output> MapOperator<Input, Output> createProjection( |
| Class<Input> inputClass, |
| Class<Output> outputClass, |
| String... fieldNames) { |
| return new MapOperator<>(new ProjectionDescriptor<>(inputClass, outputClass, fieldNames)); |
| } |
| |
| /** |
| * Creates a new instance that projects the given fields of {@link Record}s. |
| * |
| * @param fieldNames the field names for the projected fields |
| * @return the new instance |
| */ |
| public static MapOperator<Record, Record> createProjection( |
| RecordType inputType, |
| String... fieldNames) { |
| return new MapOperator<>(ProjectionDescriptor.createForRecords(inputType, fieldNames)); |
| } |
| |
| public TransformationDescriptor<InputType, OutputType> getFunctionDescriptor() { |
| return this.functionDescriptor; |
| } |
| |
| @Override |
| public Optional<CardinalityEstimator> createCardinalityEstimator( |
| final int outputIndex, |
| final Configuration configuration) { |
| Validate.inclusiveBetween(0, this.getNumOutputs() - 1, outputIndex); |
| return Optional.of(new DefaultCardinalityEstimator(1d, 1, this.isSupportingBroadcastInputs(), |
| inputCards -> inputCards[0])); |
| } |
| } |