| /* |
| * 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.beam.sdk.extensions.sql.impl.rel; |
| |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.stream.Collectors; |
| import org.apache.beam.sdk.Pipeline; |
| import org.apache.beam.sdk.transforms.PTransform; |
| import org.apache.beam.sdk.values.PCollection; |
| import org.apache.beam.sdk.values.PCollectionList; |
| import org.apache.beam.sdk.values.Row; |
| import org.apache.calcite.plan.volcano.RelSubset; |
| import org.apache.calcite.rel.RelNode; |
| |
| /** Utilities for {@code BeamRelNode}. */ |
| public class BeamSqlRelUtils { |
| |
| public static PCollection<Row> toPCollection(Pipeline pipeline, BeamRelNode node) { |
| return toPCollection(pipeline, node, new HashMap()); |
| } |
| |
| /** Transforms the inputs into a PInput. */ |
| private static PCollectionList<Row> buildPCollectionList( |
| List<RelNode> inputRels, Pipeline pipeline, Map<Integer, PCollection<Row>> cache) { |
| if (inputRels.isEmpty()) { |
| return PCollectionList.empty(pipeline); |
| } else { |
| return PCollectionList.of( |
| inputRels.stream() |
| .map(input -> BeamSqlRelUtils.toPCollection(pipeline, (BeamRelNode) input, cache)) |
| .collect(Collectors.toList())); |
| } |
| } |
| |
| /** |
| * A {@link BeamRelNode} is a recursive structure, the {@code BeamQueryPlanner} visits it with a |
| * DFS(Depth-First-Search) algorithm. |
| */ |
| static PCollection<Row> toPCollection( |
| Pipeline pipeline, BeamRelNode node, Map<Integer, PCollection<Row>> cache) { |
| PCollection<Row> output = cache.get(node.getId()); |
| if (output != null) { |
| return output; |
| } |
| |
| String name = node.getClass().getSimpleName() + "_" + node.getId(); |
| PCollectionList<Row> input = buildPCollectionList(node.getPCollectionInputs(), pipeline, cache); |
| PTransform<PCollectionList<Row>, PCollection<Row>> transform = node.buildPTransform(); |
| output = Pipeline.applyTransform(name, input, transform); |
| |
| cache.put(node.getId(), output); |
| return output; |
| } |
| |
| public static BeamRelNode getBeamRelInput(RelNode input) { |
| if (input instanceof RelSubset) { |
| // go with known best input |
| input = ((RelSubset) input).getBest(); |
| } |
| return (BeamRelNode) input; |
| } |
| } |