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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.master.balancer;
19  
20  import org.apache.hadoop.hbase.classification.InterfaceAudience;
21  import org.apache.hadoop.conf.Configuration;
22  import org.apache.hadoop.hbase.HConstants;
23  import org.apache.hadoop.hbase.master.LoadBalancer;
24  import org.apache.hadoop.util.ReflectionUtils;
25  
26  /**
27   * The class that creates a load balancer from a conf.
28   */
29  @InterfaceAudience.Private
30  public class LoadBalancerFactory {
31  
32    /**
33     * Create a loadbalancer from the given conf.
34     * @param conf
35     * @return A {@link LoadBalancer}
36     */
37    public static LoadBalancer getLoadBalancer(Configuration conf) {
38  
39      // Create the balancer
40      Class<? extends LoadBalancer> balancerKlass =
41          conf.getClass(HConstants.HBASE_MASTER_LOADBALANCER_CLASS, StochasticLoadBalancer.class,
42            LoadBalancer.class);
43      return ReflectionUtils.newInstance(balancerKlass, conf);
44  
45    }
46  }