001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018package org.apache.hadoop.hbase.zookeeper; 019 020import java.util.Collections; 021import java.util.List; 022import java.util.stream.Collectors; 023import org.apache.hadoop.hbase.Abortable; 024import org.apache.hadoop.hbase.ServerName; 025import org.apache.yetus.audience.InterfaceAudience; 026import org.apache.zookeeper.KeeperException; 027import org.slf4j.Logger; 028import org.slf4j.LoggerFactory; 029 030import org.apache.hbase.thirdparty.org.apache.commons.collections4.CollectionUtils; 031 032/** 033 * Class for tracking the region servers for a cluster. 034 */ 035@InterfaceAudience.Private 036public class RegionServerAddressTracker extends ZKListener { 037 038 private static final Logger LOG = LoggerFactory.getLogger(RegionServerAddressTracker.class); 039 040 private volatile List<ServerName> regionServers = Collections.emptyList(); 041 042 private final Abortable abortable; 043 044 public RegionServerAddressTracker(ZKWatcher watcher, Abortable abortable) { 045 super(watcher); 046 this.abortable = abortable; 047 watcher.registerListener(this); 048 loadRegionServerList(); 049 } 050 051 private void loadRegionServerList() { 052 List<String> names; 053 try { 054 names = ZKUtil.listChildrenAndWatchForNewChildren(watcher, watcher.getZNodePaths().rsZNode); 055 } catch (KeeperException e) { 056 LOG.error("failed to list region servers", e); 057 abortable.abort("failed to list region servers", e); 058 return; 059 } 060 if (CollectionUtils.isEmpty(names)) { 061 regionServers = Collections.emptyList(); 062 } else { 063 regionServers = names.stream().map(ServerName::parseServerName) 064 .collect(Collectors.collectingAndThen(Collectors.toList(), Collections::unmodifiableList)); 065 } 066 } 067 068 @Override 069 public void nodeChildrenChanged(String path) { 070 if (path.equals(watcher.getZNodePaths().rsZNode)) { 071 loadRegionServerList(); 072 } 073 } 074 075 public List<ServerName> getRegionServers() { 076 return regionServers; 077 } 078}