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.dataflow.worker.util;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkNotNull;
  
  import org.apache.beam.runners.core.StateInternalsFactory;
  import org.apache.beam.runners.core.SystemReduceFn;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  import org.apache.beam.sdk.util.AppliedCombineFn;
  import org.apache.beam.sdk.values.WindowingStrategy;
  
  /** Factory methods for creating {@link BatchGroupAlsoByWindowFn} for bounded inputs. */
  public class BatchGroupAlsoByWindowsDoFns {
    /**
     * Create a {@link BatchGroupAlsoByWindowFn} without a combine function. Depending on the {@code
     * windowFn} this will either use iterators or window sets to implement the grouping.
     *
     * @param windowingStrategy The window function and trigger to use for grouping
     * @param inputCoder the input coder to use
     */
    public static <K, V, W extends BoundedWindow>
        BatchGroupAlsoByWindowFn<K, V, Iterable<V>> createForIterable(
            WindowingStrategy<?, W> windowingStrategy,
            StateInternalsFactory<K> stateInternalsFactory,
            Coder<V> inputCoder) {
      // If the windowing strategy indicates we're doing a reshuffle, use the special-path.
      if (BatchGroupAlsoByWindowReshuffleFn.isReshuffle(windowingStrategy)) {
        return new BatchGroupAlsoByWindowReshuffleFn<>();
      } else if (BatchGroupAlsoByWindowViaIteratorsFn.isSupported(windowingStrategy)) {
        return new BatchGroupAlsoByWindowViaIteratorsFn<K, V, W>(windowingStrategy);
      }
      return new BatchGroupAlsoByWindowViaOutputBufferFn<>(
          windowingStrategy, stateInternalsFactory, SystemReduceFn.buffering(inputCoder));
    }
  
    /** Construct a {@link BatchGroupAlsoByWindowFn} using the {@code combineFn} if available. */
    public static <K, InputT, AccumT, OutputT, W extends BoundedWindow>
        BatchGroupAlsoByWindowFn<K, InputT, OutputT> create(
            final WindowingStrategy<?, W> windowingStrategy,
            final AppliedCombineFn<K, InputT, AccumT, OutputT> combineFn) {
      checkNotNull(combineFn);
      return new BatchGroupAlsoByWindowAndCombineFn<>(windowingStrategy, combineFn.getFn());
    }
  }
  