johnyangk commented on a change in pull request #104: [NEMO-183] DAG-centric translation from Beam pipeline to IR DAG URL: https://github.com/apache/incubator-nemo/pull/104#discussion_r210491889
########## File path: compiler/frontend/beam/src/main/java/edu/snu/nemo/compiler/frontend/beam/PipelineVisitor.java ########## @@ -0,0 +1,291 @@ +/* + * Copyright (C) 2018 Seoul National University + * + * Licensed 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 edu.snu.nemo.compiler.frontend.beam; + +import edu.snu.nemo.common.dag.DAG; +import edu.snu.nemo.common.dag.DAGBuilder; +import edu.snu.nemo.common.dag.Edge; +import edu.snu.nemo.common.dag.Vertex; +import org.apache.beam.sdk.Pipeline; +import org.apache.beam.sdk.runners.TransformHierarchy; +import org.apache.beam.sdk.transforms.ParDo; +import org.apache.beam.sdk.transforms.View; +import org.apache.beam.sdk.values.PValue; + +import java.util.*; + +/** + * Traverses through the given Beam pipeline to construct a DAG of Beam Transform, + * while preserving hierarchy of CompositeTransforms. + * This DAG will be later translated by {@link PipelineTranslator} into Nemo IR DAG. + */ +public final class PipelineVisitor extends Pipeline.PipelineVisitor.Defaults { + + private static final String TRANSFORM = "Transform-"; + private static final String DATAFLOW = "Dataflow-"; + + private final Stack<CompositeTransformVertex> compositeTransformVertexStack = new Stack<>(); + private CompositeTransformVertex rootVertex = null; Review comment: Are we assuming a single root? (i.e., a single source) How does this work with multiple sources? (Do we perhaps have tests to detect this?) ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
