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18 package org.apache.hadoop.hbase.zookeeper;
19
20 import java.io.IOException;
21 import java.util.List;
22 import java.util.NavigableSet;
23 import java.util.TreeSet;
24
25 import org.apache.commons.logging.Log;
26 import org.apache.commons.logging.LogFactory;
27 import org.apache.hadoop.hbase.Abortable;
28 import org.apache.hadoop.hbase.ServerName;
29 import org.apache.hadoop.hbase.HServerAddress;
30 import org.apache.hadoop.hbase.master.ServerManager;
31 import org.apache.zookeeper.KeeperException;
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47 public class DrainingServerTracker extends ZooKeeperListener {
48 private static final Log LOG = LogFactory.getLog(DrainingServerTracker.class);
49
50 private ServerManager serverManager;
51 private NavigableSet<ServerName> drainingServers = new TreeSet<ServerName>();
52 private Abortable abortable;
53
54 public DrainingServerTracker(ZooKeeperWatcher watcher,
55 Abortable abortable, ServerManager serverManager) {
56 super(watcher);
57 this.abortable = abortable;
58 this.serverManager = serverManager;
59 }
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67
68 public void start() throws KeeperException, IOException {
69 watcher.registerListener(this);
70 List<String> servers =
71 ZKUtil.listChildrenAndWatchThem(watcher, watcher.drainingZNode);
72 add(servers);
73 }
74
75 private void add(final List<String> servers) throws IOException {
76 synchronized(this.drainingServers) {
77 this.drainingServers.clear();
78 for (String n: servers) {
79 final ServerName sn = new ServerName(ZKUtil.getNodeName(n));
80 this.drainingServers.add(sn);
81 this.serverManager.addServerToDrainList(sn);
82 LOG.info("Draining RS node created, adding to list [" +
83 sn + "]");
84
85 }
86 }
87 }
88
89 private void remove(final ServerName sn) {
90 synchronized(this.drainingServers) {
91 this.drainingServers.remove(sn);
92 this.serverManager.removeServerFromDrainList(sn);
93 }
94 }
95
96 @Override
97 public void nodeDeleted(final String path) {
98 if(path.startsWith(watcher.drainingZNode)) {
99 final ServerName sn = new ServerName(ZKUtil.getNodeName(path));
100 LOG.info("Draining RS node deleted, removing from list [" +
101 sn + "]");
102 remove(sn);
103 }
104 }
105
106 @Override
107 public void nodeChildrenChanged(final String path) {
108 if(path.equals(watcher.drainingZNode)) {
109 try {
110 final List<String> newNodes =
111 ZKUtil.listChildrenAndWatchThem(watcher, watcher.drainingZNode);
112 add(newNodes);
113 } catch (KeeperException e) {
114 abortable.abort("Unexpected zk exception getting RS nodes", e);
115 } catch (IOException e) {
116 abortable.abort("Unexpected zk exception getting RS nodes", e);
117 }
118 }
119 }
120
121 }