content: /*
   * 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.runners.samza.translation;
  
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  import org.apache.beam.runners.samza.util.StateUtils;
  import org.apache.beam.sdk.Pipeline;
  import org.apache.beam.sdk.runners.TransformHierarchy;
  import org.apache.beam.sdk.transforms.DoFn;
  import org.apache.beam.sdk.transforms.ParDo;
  import org.apache.beam.sdk.transforms.reflect.DoFnSignature;
  import org.apache.beam.sdk.transforms.reflect.DoFnSignatures;
  
  /**
   * This class identifies the set of non-unique state ids by scanning the BEAM {@link Pipeline} with
   * a topological traversal.
   */
  @SuppressWarnings({
    "rawtypes", // TODO(https://github.com/apache/beam/issues/20447)
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  public class StateIdParser extends Pipeline.PipelineVisitor.Defaults {
    private final Set<String> nonUniqueStateIds = new HashSet<>();
    private final Set<String> usedStateIds = new HashSet<>();
  
    public static Set<String> scan(Pipeline pipeline) {
      final StateIdParser parser = new StateIdParser();
      pipeline.traverseTopologically(parser);
      return parser.getNonUniqueStateIds();
    }
  
    private StateIdParser() {}
  
    @Override
    public void visitPrimitiveTransform(TransformHierarchy.Node node) {
      if (node.getTransform() instanceof ParDo.MultiOutput) {
        final DoFn<?, ?> doFn = ((ParDo.MultiOutput) node.getTransform()).getFn();
        if (StateUtils.isStateful(doFn)) {
          final DoFnSignature signature = DoFnSignatures.getSignature(doFn.getClass());
          for (String stateId : signature.stateDeclarations().keySet()) {
            if (!usedStateIds.add(stateId)) {
              nonUniqueStateIds.add(stateId);
            }
          }
        }
      }
    }
  
    public Set<String> getNonUniqueStateIds() {
      return Collections.unmodifiableSet(nonUniqueStateIds);
    }
  }
  