com.taobao.adfs.zookeeper.ZookeeperClientManager.java Source code

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Here is the source code for com.taobao.adfs.zookeeper.ZookeeperClientManager.java

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/**
 * 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 com.taobao.adfs.zookeeper;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.CountDownLatch;

import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.taobao.adfs.util.Utilities;

/**
 * @author <a href=mailto:zhangwei.yangjie@gmail.com/jiwan@taobao.com>zhangwei/jiwan</a>
 */
public class ZookeeperClientManager {
    public static final Logger logger = LoggerFactory.getLogger(ZookeeperClientManager.class);

    private Map<String, ZooKeeper> zookeeperRepository = new HashMap<String, ZooKeeper>();

    public final CountDownLatch connectedSignal = new CountDownLatch(1);

    private volatile boolean connected;

    private Thread stateWatcherThread;

    private int timeout = 90000;

    private class StateWatcher implements Runnable {
        long startNotConnected;

        @Override
        public void run() {
            startNotConnected = System.currentTimeMillis();
            int margin = timeout * 2;

            while (!connected) {
                if (startNotConnected + margin < System.currentTimeMillis()) {
                    return;
                }
                try {
                    Thread.sleep(5);
                } catch (InterruptedException e) {
                    return;
                }
            }
        }
    }

    public synchronized ZooKeeper create(String connectString, int sessionTimeout) throws IOException {
        ZooKeeper zookeeper = zookeeperRepository.get(connectString);
        if (zookeeper != null) {
            Utilities.logDebug(logger, "reuse zookeeper client, address=", connectString);
            return zookeeper;
        }
        this.timeout = sessionTimeout;

        Watcher watcher = new Watcher() {
            public void process(WatchedEvent event) {
                switch (event.getType()) {
                case None: {
                    connectionEvent(event);
                    break;
                }
                }
            }
        };
        zookeeper = new ZooKeeper(connectString, sessionTimeout, watcher);
        try {
            connectedSignal.await();
        } catch (InterruptedException e) {
            Utilities.logDebug(logger, "notify by SynConnected.");
        }
        zookeeperRepository.put(connectString, zookeeper);
        Utilities.logDebug(logger, "create zookeeper client, address=", connectString);
        return zookeeper;
    }

    /**
     * 
     * if Disconnected or Expired,reconnect ZooKeeper
     * 
     * @param event
     * @throws KeeperException
     * @throws IOException
     * @throws InterruptedException
     * @throws LeaderElectionSetupException
     * @throws MetaCacheInitErrorException
     * @throws SessionExpiredException
     */
    private void connectionEvent(WatchedEvent event) {
        switch (event.getState()) {
        case Disconnected:
            logger.warn("Disconnected from ZooKeeper");
            connected = false;
            if (stateWatcherThread != null) {
                stateWatcherThread.interrupt();
            }
            stateWatcherThread = new Thread(new StateWatcher(), "ZkStateWatcher");
            stateWatcherThread.start();
            break;
        case Expired:
            logger.info("ZooKeeper session expired, close current zookeeper's connect, and reconnect zk...");
            connected = false;
            reconnect("");
            break;
        case SyncConnected:
            connected = true;
            if (stateWatcherThread != null) {
                stateWatcherThread.interrupt();
                stateWatcherThread = null;
            }
            logger.info("had connect zk....");
            connectedSignal.countDown();
        }
    }

    public boolean reconnect(String root) {
        // to do
        return true;
    }

    public synchronized void close(String connectString) {
        try {
            ZooKeeper zookeeper = zookeeperRepository.remove(connectString);
            if (zookeeper != null)
                zookeeper.close();
            Utilities.logDebug(logger, "close zookeeper client, address=", connectString);
        } catch (Throwable t) {
            Utilities.logWarn(logger, "fail to close client, address=", connectString, t);
        }
    }
}