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 org.apache.beam.runners.direct.DirectGroupByKey.DirectGroupByKeyOnly;
  import org.apache.beam.runners.local.StructuralKey;
  import org.apache.beam.sdk.transforms.PTransform;
  import org.apache.beam.sdk.values.PCollection;
  
  /** A factory that creates {@link UncommittedBundle UncommittedBundles}. */
  interface BundleFactory {
    /**
     * Create an {@link UncommittedBundle} from an empty input. Elements added to the bundle do not
     * belong to a {@link PCollection}.
     *
     * <p>For use in creating inputs to root transforms.
     */
    <T> UncommittedBundle<T> createRootBundle();
  
    /**
     * Create an {@link UncommittedBundle} from the specified input. Elements added to the bundle
     * belong to the {@code output} {@link PCollection}.
     */
    <T> UncommittedBundle<T> createBundle(PCollection<T> output);
  
    /**
     * Create an {@link UncommittedBundle} with the specified keys at the specified step. For use by
     * {@link DirectGroupByKeyOnly} {@link PTransform PTransforms}. Elements added to the bundle
     * belong to the {@code output} {@link PCollection}.
     */
    <K, T> UncommittedBundle<T> createKeyedBundle(StructuralKey<K> key, PCollection<T> output);
  }
  