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  
19  package org.apache.hadoop.hbase.metrics;
20  
21  import java.util.List;
22  
23  import junit.framework.Assert;
24  
25  import org.apache.hadoop.hbase.SmallTests;
26  import org.apache.hadoop.hbase.util.Pair;
27  import org.junit.Test;
28  import org.junit.experimental.categories.Category;
29  
30  @Category(SmallTests.class)
31  public class TestExactCounterMetric {
32  
33    @Test
34    public void testBasic() {
35      final ExactCounterMetric counter = new ExactCounterMetric("testCounter", null);
36      for (int i = 1; i <= 10; i++) {
37        for (int j = 0; j < i; j++) {
38          counter.update(i + "");
39        }
40      }
41      
42      List<Pair<String, Long>> topFive = counter.getTop(5);
43      Long i = 10L;
44      for (Pair<String, Long> entry : topFive) {
45        Assert.assertEquals(i + "", entry.getFirst());
46        Assert.assertEquals(i, entry.getSecond());
47        i--;
48      }
49    }
50  }