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1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  package org.apache.hadoop.hbase.regionserver;
20  
21  import java.net.InetSocketAddress;
22  import java.util.List; 
23  
24  import org.apache.hadoop.classification.InterfaceAudience;
25  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.ServerName;
26  
27  /**
28   * Abstraction that allows different modules in RegionServer to update/get
29   * the favored nodes information for regions. 
30   */
31  @InterfaceAudience.Private
32  interface FavoredNodesForRegion {
33    /**
34     * Used to update the favored nodes mapping when required.
35     * @param encodedRegionName
36     * @param favoredNodes
37     */
38    void updateRegionFavoredNodesMapping(String encodedRegionName, List<ServerName> favoredNodes);
39  
40    /**
41     * Get the favored nodes mapping for this region. Used when the HDFS create API
42     * is invoked to pass in favored nodes hints for new region files.
43     * @param encodedRegionName
44     * @return array containing the favored nodes' InetSocketAddresses
45     */
46    InetSocketAddress[] getFavoredNodesForRegion(String encodedRegionName);
47  }