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 org.apache.flink.api.common.functions.MapFunction;
  
  /**
   * A map function that outputs the input element without any change.
   *
   * @param <T> Input element type.
   */
  public class FlinkIdentityFunction<T> implements MapFunction<T, T> {
  
    private static final FlinkIdentityFunction<?> INSTANCE = new FlinkIdentityFunction<>();
  
    @SuppressWarnings("unchecked")
    public static <T> FlinkIdentityFunction<T> of() {
      return (FlinkIdentityFunction) INSTANCE;
    }
  
    private FlinkIdentityFunction() {}
  
    @Override
    public T map(T value) {
      return value;
    }
  }
  