001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hdfs.util;
019
020/**
021 * A Holder is simply a wrapper around some other object. This is useful
022 * in particular for storing immutable values like boxed Integers in a
023 * collection without having to do the "lookup" of the value twice.
024 */
025public class Holder<T> {
026  public T held;
027  
028  public Holder(T held) {
029    this.held = held;
030  }
031  
032  @Override
033  public String toString() {
034    return String.valueOf(held);
035  }
036}