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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  
19  package org.apache.hadoop.hbase.regionserver;
20  
21  import org.apache.hadoop.hbase.metrics.BaseSource;
22  
23  /**
24   * This interface will be implemented by a MetricsSource that will export metrics from
25   * multiple regions into the hadoop metrics system.
26   */
27  public interface MetricsRegionAggregateSource extends BaseSource {
28  
29    /**
30     * The name of the metrics
31     */
32    String METRICS_NAME = "Regions";
33  
34    /**
35     * The name of the metrics context that metrics will be under.
36     */
37    String METRICS_CONTEXT = "regionserver";
38  
39    /**
40     * Description
41     */
42    String METRICS_DESCRIPTION = "Metrics about HBase RegionServer regions and tables";
43  
44    /**
45     * The name of the metrics context that metrics will be under in jmx
46     */
47    String METRICS_JMX_CONTEXT = "RegionServer,sub=" + METRICS_NAME;
48  
49    String NUM_REGIONS = "numRegions";
50    String NUMBER_OF_REGIONS_DESC = "Number of regions in the metrics system";
51  
52    /**
53     * Register a MetricsRegionSource as being open.
54     *
55     * @param source the source for the region being opened.
56     */
57    void register(MetricsRegionSource source);
58  
59    /**
60     * Remove a region's source. This is called when a region is closed.
61     *
62     * @param source The region to remove.
63     */
64    void deregister(MetricsRegionSource source);
65  }