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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  
20  package org.apache.hadoop.hbase.zookeeper;
21  
22  import org.apache.hadoop.conf.Configuration;
23  import org.apache.hadoop.hbase.HBaseConfiguration;
24  import org.apache.hadoop.hbase.HBaseInterfaceAudience;
25  import org.apache.hadoop.hbase.HConstants;
26  import org.apache.hadoop.hbase.ServerName;
27  import org.apache.hadoop.hbase.classification.InterfaceAudience;
28  
29  import java.util.LinkedList;
30  import java.util.List;
31  
32  /**
33   * Tool for reading ZooKeeper servers from HBase XML configuration and producing
34   * a line-by-line list for use by bash scripts.
35   */
36  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.TOOLS)
37  public class ZKServerTool {
38    public static ServerName[] readZKNodes(Configuration conf) {
39      List<ServerName> hosts = new LinkedList<ServerName>();
40      String quorum = conf.get(HConstants.ZOOKEEPER_QUORUM, HConstants.LOCALHOST);
41  
42      String[] values = quorum.split(",");
43      for (String value : values) {
44        String[] parts = value.split(":");
45        String host = parts[0];
46        int port = HConstants.DEFAULT_ZOOKEPER_CLIENT_PORT;
47        if (parts.length > 1) {
48          port = Integer.parseInt(parts[1]);
49        }
50        hosts.add(ServerName.valueOf(host, port, -1));
51      }
52      return hosts.toArray(new ServerName[hosts.size()]);
53    }
54  
55    /**
56     * Run the tool.
57     * @param args Command line arguments.
58     */
59    public static void main(String args[]) {
60      for(ServerName server: readZKNodes(HBaseConfiguration.create())) {
61        // bin/zookeeper.sh relies on the "ZK host" string for grepping which is case sensitive.
62        System.out.println("ZK host: " + server.getHostname());
63      }
64    }
65  }