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.spark.translation;
  
  import java.util.Collection;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  import org.apache.beam.sdk.transforms.windowing.PaneInfo;
  import org.apache.beam.sdk.transforms.windowing.Window.Assign;
  import org.apache.beam.sdk.transforms.windowing.WindowFn;
  import org.apache.beam.sdk.values.WindowedValue;
  import org.apache.beam.sdk.values.WindowedValues;
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.Iterables;
  import org.apache.spark.api.java.function.Function;
  import org.joda.time.Instant;
  
  /** An implementation of {@link Assign} for the Spark runner. */
  public class SparkAssignWindowFn<T, W extends BoundedWindow>
      implements Function<WindowedValue<T>, WindowedValue<T>> {
  
    private final WindowFn<? super T, W> fn;
  
    public SparkAssignWindowFn(WindowFn<? super T, W> fn) {
      this.fn = fn;
    }
  
    @Override
    @SuppressWarnings("unchecked")
    public WindowedValue<T> call(WindowedValue<T> windowedValue) throws Exception {
      final BoundedWindow boundedWindow = Iterables.getOnlyElement(windowedValue.getWindows());
      final T element = windowedValue.getValue();
      final Instant timestamp = windowedValue.getTimestamp();
      Collection<W> windows =
          ((WindowFn<T, W>) fn)
              .assignWindows(
                  ((WindowFn<T, W>) fn).new AssignContext() {
                    @Override
                    public T element() {
                      return element;
                    }
  
                    @Override
                    public Instant timestamp() {
                      return timestamp;
                    }
  
                    @Override
                    public BoundedWindow window() {
                      return boundedWindow;
                    }
                  });
      return WindowedValues.of(element, timestamp, windows, PaneInfo.NO_FIRING);
    }
  }
  