| /** |
| * 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 kafka.consumer |
| |
| import scala.collection.JavaConversions._ |
| import kafka.utils.{ZkUtils, ZKStringSerializer, Logging} |
| import org.I0Itec.zkclient.{IZkStateListener, IZkChildListener, ZkClient} |
| import org.apache.zookeeper.Watcher.Event.KeeperState |
| |
| class ZookeeperTopicEventWatcher(val config:ConsumerConfig, |
| val eventHandler: TopicEventHandler[String]) extends Logging { |
| |
| val lock = new Object() |
| |
| private var zkClient: ZkClient = new ZkClient(config.zkConnect, config.zkSessionTimeoutMs, |
| config.zkConnectionTimeoutMs, ZKStringSerializer) |
| |
| startWatchingTopicEvents() |
| |
| private def startWatchingTopicEvents() { |
| val topicEventListener = new ZkTopicEventListener() |
| ZkUtils.makeSurePersistentPathExists(zkClient, ZkUtils.BrokerTopicsPath) |
| |
| zkClient.subscribeStateChanges( |
| new ZkSessionExpireListener(topicEventListener)) |
| |
| val topics = zkClient.subscribeChildChanges( |
| ZkUtils.BrokerTopicsPath, topicEventListener).toList |
| |
| // call to bootstrap topic list |
| topicEventListener.handleChildChange(ZkUtils.BrokerTopicsPath, topics) |
| } |
| |
| private def stopWatchingTopicEvents() { zkClient.unsubscribeAll() } |
| |
| def shutdown() { |
| lock.synchronized { |
| info("Shutting down topic event watcher.") |
| if (zkClient != null) { |
| stopWatchingTopicEvents() |
| zkClient.close() |
| zkClient = null |
| } |
| else |
| warn("Cannot shutdown already shutdown topic event watcher.") |
| } |
| } |
| |
| class ZkTopicEventListener extends IZkChildListener { |
| |
| @throws(classOf[Exception]) |
| def handleChildChange(parent: String, children: java.util.List[String]) { |
| lock.synchronized { |
| try { |
| if (zkClient != null) { |
| val latestTopics = zkClient.getChildren(ZkUtils.BrokerTopicsPath).toList |
| debug("all topics: %s".format(latestTopics)) |
| |
| eventHandler.handleTopicEvent(latestTopics) |
| } |
| } |
| catch { |
| case e => |
| error("error in handling child changes", e) |
| } |
| } |
| } |
| |
| } |
| |
| class ZkSessionExpireListener(val topicEventListener: ZkTopicEventListener) |
| extends IZkStateListener { |
| |
| @throws(classOf[Exception]) |
| def handleStateChanged(state: KeeperState) { } |
| |
| @throws(classOf[Exception]) |
| def handleNewSession() { |
| lock.synchronized { |
| if (zkClient != null) { |
| info( |
| "ZK expired: resubscribing topic event listener to topic registry") |
| zkClient.subscribeChildChanges( |
| ZkUtils.BrokerTopicsPath, topicEventListener) |
| } |
| } |
| } |
| } |
| } |
| |