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.wrappers.streaming;
  
  import java.nio.ByteBuffer;
  import org.apache.beam.runners.core.KeyedWorkItem;
  import org.apache.beam.runners.flink.adapter.FlinkKey;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.values.WindowedValue;
  import org.apache.flink.api.common.typeinfo.TypeInformation;
  import org.apache.flink.api.java.functions.KeySelector;
  import org.apache.flink.api.java.typeutils.ResultTypeQueryable;
  import org.apache.flink.api.java.typeutils.ValueTypeInfo;
  
  /**
   * {@link KeySelector} that retrieves a key from a {@link KeyedWorkItem}. This will return the key
   * as encoded by the provided {@link Coder} in a {@link ByteBuffer}. This ensures that all key
   * comparisons/hashing happen on the encoded form.
   */
  public class WorkItemKeySelector<K, V>
      implements KeySelector<WindowedValue<KeyedWorkItem<K, V>>, FlinkKey>,
          ResultTypeQueryable<FlinkKey> {
  
    private final Coder<K> keyCoder;
  
    public WorkItemKeySelector(Coder<K> keyCoder) {
      this.keyCoder = keyCoder;
    }
  
    @Override
    public FlinkKey getKey(WindowedValue<KeyedWorkItem<K, V>> value) throws Exception {
      K key = value.getValue().key();
      return FlinkKey.of(key, keyCoder);
    }
  
    @Override
    public TypeInformation<FlinkKey> getProducedType() {
      return ValueTypeInfo.of(FlinkKey.class);
    }
  }
  