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.direct;
  
  import java.util.Collection;
  import org.apache.beam.sdk.Pipeline;
  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.PInput;
  
  /**
   * Provides {@link CommittedBundle bundles} that will be provided to the {@link PTransform
   * PTransforms} that are at the root of a {@link Pipeline}.
   */
  interface RootInputProvider<T, ShardT, InputT extends PInput> {
    /**
     * Get the initial inputs for the {@link AppliedPTransform}. The {@link AppliedPTransform} will be
     * provided with these {@link CommittedBundle bundles} as input when the {@link Pipeline} runs.
     *
     * <p>For source transforms, these should be sufficient that, when provided to the evaluators
     * produced by {@link TransformEvaluatorFactory#forApplication(AppliedPTransform,
     * CommittedBundle)}, all of the elements contained in the source are eventually produced.
     *
     * @param transform the {@link AppliedPTransform} to get initial inputs for.
     * @param targetParallelism the target amount of parallelism to obtain from the source. Must be
     *     greater than or equal to 1.
     */
    Collection<CommittedBundle<ShardT>> getInitialInputs(
        AppliedPTransform<InputT, PCollection<T>, PTransform<InputT, PCollection<T>>> transform,
        int targetParallelism)
        throws Exception;
  }
  