/**
 * 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.crunch.fn;

import org.apache.crunch.MapFn;

public class IdentityFn<T> extends MapFn<T, T> {

  private static final IdentityFn<Object> INSTANCE = new IdentityFn<Object>();

  @SuppressWarnings("unchecked")
  public static <T> IdentityFn<T> getInstance() {
    return (IdentityFn<T>) INSTANCE;
  }

  // Non-instantiable
  private IdentityFn() {
  }

  @Override
  public T map(T input) {
    return input;
  }
}