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.flink.translation.functions;
  
  import java.util.Collection;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  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.flink.api.common.functions.FlatMapFunction;
  import org.apache.flink.util.Collector;
  
  /**
   * Flink {@link FlatMapFunction} for implementing {@link
   * org.apache.beam.sdk.transforms.windowing.Window.Assign}.
   */
  public class FlinkAssignWindows<T, W extends BoundedWindow>
      implements FlatMapFunction<WindowedValue<T>, WindowedValue<T>> {
  
    private final WindowFn<T, W> windowFn;
  
    public FlinkAssignWindows(WindowFn<T, W> windowFn) {
      this.windowFn = windowFn;
    }
  
    @Override
    public void flatMap(WindowedValue<T> input, Collector<WindowedValue<T>> collector)
        throws Exception {
      Collection<W> windows = windowFn.assignWindows(new FlinkAssignContext<>(windowFn, input));
      for (W window : windows) {
        collector.collect(
            WindowedValues.of(input.getValue(), input.getTimestamp(), window, input.getPaneInfo()));
      }
    }
  }
  