com.asuraiv.coordination.Master.java Source code

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Here is the source code for com.asuraiv.coordination.Master.java

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/*
 * @(#)Master.java $version 2016. 1. 4.
 *
 * Copyright 2007 NHN Corp. All rights Reserved. 
 * NHN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.asuraiv.coordination;

import java.io.IOException;
import java.util.List;

import org.apache.zookeeper.AsyncCallback;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.CollectionUtils;

import com.asuraiv.coordination.enums.TaskStatus;
import com.asuraiv.coordination.enums.WorkerStatus;
import com.asuraiv.coordination.util.ZooKeeperUtils;

/**
 * @author Jupyo Hong
 */
public class Master extends Thread implements Watcher, AsyncCallback.ChildrenCallback {

    private static final Logger LOG = LoggerFactory.getLogger(Master.class);

    private ZooKeeperUtils zkUtils;

    /**
     * @param string
     * @throws IOException 
     */
    public Master(String hostPort) throws IOException {
        zkUtils = new ZooKeeperUtils(new ZooKeeper(hostPort, 15000, this));
    }

    /**
     * @param event
     * @see org.apache.zookeeper.Watcher#process(org.apache.zookeeper.WatchedEvent)
     */
    public void process(WatchedEvent event) {
        //  Watcher ?
        zkUtils.asyncGetChildren("/tasks", true, /* AsyncCallback.ChildrenCallback */this, null);
    }

    /**
     * @param rc
     * @param path
     * @param ctx
     * @param children
     * @see org.apache.zookeeper.AsyncCallback.ChildrenCallback#processResult(int, java.lang.String, java.lang.Object, java.util.List)
     */
    public void processResult(int rc, String path, Object ctx, List<String> children) {

        if (CollectionUtils.isEmpty(children)) {
            return;
        }

        for (String task : children) {

            String taskStatus = zkUtils.getData("/tasks/" + task);
            if (!TaskStatus.WAITING.name().equals(taskStatus)) {
                continue;
            }

            //  Worker .
            String availableWorker = getAvailableWorkers();

            LOG.info("[MASTER] {} ? {} ?  .", availableWorker, task);
            zkUtils.asyncCreate("/assign/" + availableWorker, task.getBytes(), Ids.OPEN_ACL_UNSAFE,
                    CreateMode.EPHEMERAL, null, null);

            //  Watcher ?
            zkUtils.asyncGetChildren("/tasks", true, /* AsyncCallback.ChildrenCallback */this, null);
        }
    }

    /**
     *  Worker(Idle ??) .
     * 
     * @return
     */
    private String getAvailableWorkers() {

        while (true) {

            List<String> workers = zkUtils.getChildren("/workers", false, null);
            for (String worker : workers) {

                String workerStatus = zkUtils.getData("/workers/" + worker);

                if (WorkerStatus.IDLE.name().equals(workerStatus)) {
                    //  worker   
                    return worker;
                }
            }

            LOG.info("[MASTER]  Worker .  ...");

            try {
                Thread.currentThread().sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    public void run() {

        LOG.info("[MASTER]  ?...");

        zkUtils.asyncGetChildren("/tasks", true, /* AsyncCallback.ChildrenCallback */this, null);

        try {
            synchronized (this) {
                while (true) {
                    wait();
                }
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}