| /* |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.hadoop.hbase.zookeeper; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.hbase.Abortable; |
| import org.apache.hadoop.hbase.ClusterId; |
| import org.apache.hadoop.hbase.DeserializationException; |
| import org.apache.zookeeper.KeeperException; |
| |
| /** |
| * Publishes and synchronizes a unique identifier specific to a given HBase |
| * cluster. The stored identifier is read from the file system by the active |
| * master on startup, and is subsequently available to all watchers (including |
| * clients). |
| */ |
| @InterfaceAudience.Private |
| public class ZKClusterId { |
| private ZooKeeperWatcher watcher; |
| private Abortable abortable; |
| private String id; |
| |
| public ZKClusterId(ZooKeeperWatcher watcher, Abortable abortable) { |
| this.watcher = watcher; |
| this.abortable = abortable; |
| } |
| |
| public boolean hasId() { |
| return getId() != null; |
| } |
| |
| public String getId() { |
| try { |
| if (id == null) { |
| id = readClusterIdZNode(watcher); |
| } |
| } catch (KeeperException ke) { |
| abortable.abort("Unexpected exception from ZooKeeper reading cluster ID", |
| ke); |
| } |
| return id; |
| } |
| |
| public static String readClusterIdZNode(ZooKeeperWatcher watcher) |
| throws KeeperException { |
| if (ZKUtil.checkExists(watcher, watcher.clusterIdZNode) != -1) { |
| byte [] data = ZKUtil.getData(watcher, watcher.clusterIdZNode); |
| if (data != null) { |
| try { |
| return ClusterId.parseFrom(data).toString(); |
| } catch (DeserializationException e) { |
| throw ZKUtil.convert(e); |
| } |
| } |
| } |
| return null; |
| } |
| |
| public static void setClusterId(ZooKeeperWatcher watcher, ClusterId id) |
| throws KeeperException { |
| ZKUtil.createSetData(watcher, watcher.clusterIdZNode, id.toByteArray()); |
| } |
| } |