com.bloomreach.zk.replicate.ZookeeperDataReplicator.java Source code

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Here is the source code for com.bloomreach.zk.replicate.ZookeeperDataReplicator.java

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/**
 * Copyright 2014-2015 BloomReach, Inc.
 * Licensed 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.bloomreach.zk.replicate;

import org.apache.log4j.Logger;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.ZooKeeper;
import org.apache.commons.lang3.exception.ExceptionUtils;

/**
 * Zookeeper Data Replicator. Given a copy of {@link com.bloomreach.zk.replicate.ZkDataNode}
 * it iterates over it and constructs the same structure on the given destination {@link org.apache.zookeeper}
 * destination end point.
 *
 * @author nitin
 * @since 01/06/2015
 */
public class ZookeeperDataReplicator {
    private static Logger logger = Logger.getLogger(ZookeeperDataReplicator.class);

    /* Represents the zookeper Data Node */
    private ZkDataNode sourceZkDataNode;

    /* Represents the root Zk Clone Path */
    private String sourceCloneZkPath;

    /* Represents the zookeper Handle */
    private ZooKeeper zkHandle;

    /**
     * Constructs a Zookeeper Data Replicators with destination Zookeper Host, the root path to replicate
     * and the zkData to copy from
     *
     * @param destinationZkServer The destination Zookeper Host
     * @param rootReplicatePath The root path to replicate
     * @param sourceZkData The Zookeeper data to copy from
     */
    public ZookeeperDataReplicator(String destinationZkServer, String rootReplicatePath, ZkDataNode sourceZkData) {
        this.sourceZkDataNode = sourceZkData;
        this.sourceCloneZkPath = rootReplicatePath;
        this.zkHandle = ZKConnectionManager.connectToZookeeper(destinationZkServer);
    }

    /**
     * Replicate data to Destination Zk based on the incoming zk data structure
     * Refer {@link #ZookeeperDataReplicator(String destinationZkServer, String rootReplicatePath, ZkDataNode sourceZkData)}
     */
    public void replicate() throws ZkDataTraversalException {
        try {
            ZKAccessUtils.validateAndCreateZkPath(zkHandle, sourceCloneZkPath, null);
            writeAndFlushData(sourceZkDataNode);
        } catch (Exception e) {
            throw new ZkDataTraversalException(ExceptionUtils.getStackTrace(e));
        }
    }

    /**
     * Create Path and Flush out Data for the corresponding Zookeeper node and its children.
     *
     * @param node The Zookeeper data to copy from
     * @throws KeeperException
     * @throws InterruptedException
     */
    private void writeAndFlushData(ZkDataNode node) throws KeeperException, InterruptedException {
        String path = node.getFQPath();
        if (ZKAccessUtils.zkPathExists(zkHandle, path)) {
            logger.info("Path Exists: Setting data...  " + path);
            ZKAccessUtils.setDataOnZkNode(zkHandle, path, node.getNodeData());
        } else {
            logger.info("Path does not exist. Creating now... " + path);
            ZKAccessUtils.validateAndCreateZkPath(zkHandle, path, node.getNodeData());
        }
        for (ZkDataNode child : node.getAllChildren()) {
            writeAndFlushData(child);
        }
    }
}