com.chinamobile.bcbsp.sync.SynchronizationServer.java Source code

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Here is the source code for com.chinamobile.bcbsp.sync.SynchronizationServer.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.chinamobile.bcbsp.sync;

import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs.Ids;

import com.chinamobile.bcbsp.BSPConfiguration;
import com.chinamobile.bcbsp.Constants;
import com.chinamobile.bcbsp.thirdPartyInterface.Zookeeper.BSPIds;
import com.chinamobile.bcbsp.thirdPartyInterface.Zookeeper.BSPZookeeper;
import com.chinamobile.bcbsp.thirdPartyInterface.Zookeeper.impl.BSPCreateModeImpl;
import com.chinamobile.bcbsp.thirdPartyInterface.Zookeeper.impl.BSPZookeeperImpl;

/**
 * SynchronizationServer This is an implementation for ZooKeeper.
 * @version 1.0
 */
public class SynchronizationServer implements SynchronizationServerInterface, Watcher {
    /**The log of the class.*/
    private static final Log LOG = LogFactory.getLog(SynchronizationServer.class);
    /**The configuration of the bsp.*/
    private BSPConfiguration conf;
    /**The zookeeper of the bsp.*/
    private BSPZookeeper bspzk = null;
    /**The zookeeper address.*/
    private final String zookeeperAddr;
    /**The zookeeper of the bsp.*/
    private final String bspZKRoot;
    /**The volatile variable of the thread.*/
    private volatile Integer mutex = 0;

    /**
     * constructor of the class.
     */
    public SynchronizationServer() {
        this.conf = new BSPConfiguration();
        this.zookeeperAddr = conf.get(Constants.ZOOKEEPER_QUORUM) + ":"
                + conf.getInt(Constants.ZOOKEPER_CLIENT_PORT, Constants.DEFAULT_ZOOKEPER_CLIENT_PORT);
        this.bspZKRoot = Constants.BSPJOB_ZOOKEEPER_DIR_ROOT;
    }

    /** For JUnit test. */
    public SynchronizationServer(BSPConfiguration conf) {
        this.conf = conf;
        this.zookeeperAddr = conf.get(Constants.ZOOKEEPER_QUORUM) + ":"
                + conf.getInt(Constants.ZOOKEPER_CLIENT_PORT, Constants.DEFAULT_ZOOKEPER_CLIENT_PORT);
        this.bspZKRoot = Constants.BSPJOB_ZOOKEEPER_DIR_ROOT;
    }

    @Override
    public boolean startServer() {
        try {
            this.bspzk = new BSPZookeeperImpl(this.zookeeperAddr, 3000, this);
            if (this.bspzk != null) {
                if (bspzk.equaltoStat(this.bspZKRoot, false)) {
                    deleteZKNodes(this.bspZKRoot);
                }
                this.bspzk.create(this.bspZKRoot, new byte[0], Ids.OPEN_ACL_UNSAFE,
                        new BSPCreateModeImpl().getPERSISTENT());
            }
            return true;
        } catch (Exception e) {
            LOG.error("[startServer]", e);
            return false;
        }
    }

    @Override
    public boolean stopServer() {
        try {
            deleteZKNodes(this.bspZKRoot);
            return true;
        } catch (Exception e) {
            LOG.error("[stopServer]", e);
            return false;
        }
    }

    /**
     * To delete zookeeper node.
     * @param node the String of the node.
     * @throws Exception the Exception.
     */
    private void deleteZKNodes(String node) throws Exception {
        if (bspzk.equaltoStat(node, false)) {
            List<String> children = this.bspzk.getChildren(node, false);
            if (children.size() > 0) {
                for (String child : children) {
                    deleteZKNodes(node + "/" + child);
                }
            }
            this.bspzk.delete(node, this.bspzk.exists(node, false).getVersion());
        }
    }

    @Override
    public void process(WatchedEvent event) {
        synchronized (mutex) {
            mutex.notify();
        }
    }
}