cn.lhfei.zookeeper.ch01.Client.java Source code

Introduction

Here is the source code for cn.lhfei.zookeeper.ch01.Client.java

Source

/*
 * Copyright 2010-2011 the original author or authors.
 *
 * 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 cn.lhfei.zookeeper.ch01;

import java.io.IOException;
import java.util.Random;

import org.apache.zookeeper.AsyncCallback.StringCallback;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.Code;
import org.apache.zookeeper.KeeperException.ConnectionLossException;
import org.apache.zookeeper.KeeperException.NodeExistsException;
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 cn.lhfei.zookeeper.config.ZKConfiguration;

/**
 * @version 1.0.0
 *
 * @author Hefei Li
 *
 * @since Feb 26, 2016
 */
public class Client implements Watcher {
    private static final Logger log = LoggerFactory.getLogger(Client.class);
    private static final String CURRENT_NODE = "/zk";

    private Random random = new Random(this.hashCode());
    private ZooKeeper zk;
    private String status;
    private String hostPort;
    private String serverId = Integer.toHexString(random.nextInt());
    private static boolean isLeader = false;

    public Client(String host, int port) {
        this.hostPort = host + ":" + port;
    }

    @Override
    public void process(WatchedEvent event) {
        log.info("{}", event);
    }

    void startZK() throws IOException {
        zk = new ZooKeeper(hostPort, 1500, this);
    }

    void register() throws KeeperException, InterruptedException {
        zk.create(CURRENT_NODE, "HEFEI-LI".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL, stringCallback,
                null);
    }

    String queueCommand(String command) throws Exception {
        while (true) {
            try {
                String name = zk.create(CURRENT_NODE, command.getBytes(), Ids.OPEN_ACL_UNSAFE,
                        CreateMode.EPHEMERAL_SEQUENTIAL);
                return name;
            } catch (NodeExistsException e) {
                throw new Exception(" already appears to be running");
            } catch (ConnectionLossException e) {
            }

        }
    }

    StringCallback stringCallback = new StringCallback() {

        @Override
        public void processResult(int rc, String path, Object ctx, String name) {
            switch (Code.get(rc)) {
            case CONNECTIONLOSS:
                try {
                    register();

                    log.info("Registered successfully: {}", serverId);
                } catch (KeeperException | InterruptedException e) {
                    log.error(e.getMessage(), e);
                }
                break;
            case OK:
                log.warn("Already registered: {}", serverId);
                break;
            case NODEEXISTS:

                break;
            default:
                log.error("Something went wrong: {}", KeeperException.create(Code.get(rc), path));
            }
        }
    };

    public static void main(String[] args) throws Exception {
        Client c = new Client(ZKConfiguration.ZK_SERVER_80, ZKConfiguration.ZK_CLIENT_PORT);
        c.startZK();

        String name = c.queueCommand("test");

        log.info("Created {}", name);
    }

}