1 /** 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 package org.apache.hadoop.hdfs.util; 19 20 /** 21 * A Holder is simply a wrapper around some other object. This is useful 22 * in particular for storing immutable values like boxed Integers in a 23 * collection without having to do the "lookup" of the value twice. 24 */ 25 public class Holder<T> { 26 public T held; 27 Holder(T held)28 public Holder(T held) { 29 this.held = held; 30 } 31 32 @Override toString()33 public String toString() { 34 return String.valueOf(held); 35 } 36 } 37