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