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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.master.balancer;
20  
21  import org.apache.commons.logging.Log;
22  import org.apache.commons.logging.LogFactory;
23  import org.apache.hadoop.hbase.classification.InterfaceAudience;
24  import org.apache.hadoop.hbase.Chore;
25  import org.apache.hadoop.hbase.HBaseIOException;
26  import org.apache.hadoop.hbase.master.HMaster;
27  
28  import java.io.IOException;
29  
30  /**
31   * Chore that will call HMaster.balance{@link org.apache.hadoop.hbase.master.HMaster#balance()} when
32   * needed.
33   */
34  @InterfaceAudience.Private
35  public class BalancerChore extends Chore {
36    private static final Log LOG = LogFactory.getLog(BalancerChore.class);
37  
38    private final HMaster master;
39  
40    public BalancerChore(HMaster master) {
41      super(master.getServerName() + "-BalancerChore",
42          master.getConfiguration().getInt("hbase.balancer.period", 300000),
43          master);
44      this.master = master;
45    }
46  
47    @Override
48    protected void chore() {
49      try {
50        master.balance();
51      } catch (IOException e) {
52        LOG.error("Failed to balance.", e);
53      }
54    }
55  }