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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.hbase.util;
19  
20  import java.util.concurrent.atomic.AtomicLong;
21  
22  import org.apache.hadoop.hbase.classification.InterfaceAudience;
23  
24  /**
25   * Utilities related to atomic operations.
26   */
27  @InterfaceAudience.Private
28  public class AtomicUtils {
29    /**
30     * Updates a AtomicLong which is supposed to maintain the minimum values. This method is not
31     * synchronized but is thread-safe.
32     */
33    public static void updateMin(AtomicLong min, long value) {
34      while (true) {
35        long cur = min.get();
36        if (value >= cur) {
37          break;
38        }
39  
40        if (min.compareAndSet(cur, value)) {
41          break;
42        }
43      }
44    }
45  
46    /**
47     * Updates a AtomicLong which is supposed to maintain the maximum values. This method is not
48     * synchronized but is thread-safe.
49     */
50    public static void updateMax(AtomicLong max, long value) {
51      while (true) {
52        long cur = max.get();
53        if (value <= cur) {
54          break;
55        }
56  
57        if (max.compareAndSet(cur, value)) {
58          break;
59        }
60      }
61    }
62  
63  }