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.sdk.util.construction;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkArgument;
  
  import java.util.Collection;
  import java.util.Map;
  import org.apache.beam.sdk.runners.AppliedPTransform;
  import org.apache.beam.sdk.transforms.PTransform;
  import org.apache.beam.sdk.values.PCollection;
  import org.apache.beam.sdk.values.PValue;
  import org.apache.beam.sdk.values.TupleTag;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;
  
  /** Utilities for extracting subsets of inputs from an {@link AppliedPTransform}. */
  public class TransformInputs {
    /**
     * Gets all inputs of the {@link AppliedPTransform} that are not returned by {@link
     * PTransform#getAdditionalInputs()}.
     */
    public static Collection<PValue> nonAdditionalInputs(AppliedPTransform<?, ?, ?> application) {
      ImmutableList.Builder<PValue> mainInputs = ImmutableList.builder();
      PTransform<?, ?> transform = application.getTransform();
      for (Map.Entry<TupleTag<?>, PCollection<?>> input : application.getInputs().entrySet()) {
        if (!transform.getAdditionalInputs().containsKey(input.getKey())) {
          mainInputs.add(input.getValue());
        }
      }
      checkArgument(
          !mainInputs.build().isEmpty() || application.getInputs().isEmpty(),
          "Expected at least one main input if any inputs exist");
      return mainInputs.build();
    }
  }
  