package com.freud.zk.curator;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.leader.LeaderSelector;
import org.apache.curator.framework.recipes.leader.LeaderSelectorListener;
import org.apache.curator.framework.state.ConnectionState;
import org.apache.curator.retry.ExponentialBackoffRetry;

/**
 * 
 * Zookeeper - Curator - Leader Election
 * 
 * @author Freud
 *
 */
public class CuratorLeaderElectionZookeeper {

	private static final int SECOND = 1000;
	private static int count = 1;

	public static void main(String[] args) throws Exception {
		ExecutorService service = Executors.newFixedThreadPool(3);
		for (int i = 0; i < 3; i++) {
			final int index = i;
			service.submit(new Runnable() {
				public void run() {
					try {
						new CuratorLeaderElectionZookeeper().schedule(index);
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
			});
		}

		Thread.sleep(10 * SECOND);
		service.shutdownNow();
	}

	private void schedule(final int thread) throws Exception {
		CuratorFramework client = this.getStartedClient(thread);
		String path = "/leader_selector";
		if (client.checkExists().forPath(path) == null) {
			client.create().creatingParentsIfNeeded().forPath(path);
		}
		LeaderSelector selector = new LeaderSelector(client, path, new LeaderSelectorListener() {
			public void stateChanged(CuratorFramework cf, ConnectionState state) {
				System.out.println("Thread [" + thread + "][Callback] State changed to :" + state.name());
			}

			public void takeLeadership(CuratorFramework cf) throws Exception {
				Thread.sleep(1 * SECOND);
				System.out.println("Thread [" + thread + "]Do some business work...timestamp ["
						+ System.currentTimeMillis() + "] times [" + count++ + "]");
			}
		});

		// 自动重新部署竞选
		selector.autoRequeue();
		selector.start();
	}

	private CuratorFramework getStartedClient(final int thread) {
		RetryPolicy rp = new ExponentialBackoffRetry(1 * SECOND, 3);
		// Fluent风格创建
		CuratorFramework cfFluent = CuratorFrameworkFactory.builder().connectString("localhost:2181")
				.sessionTimeoutMs(5 * SECOND).connectionTimeoutMs(3 * SECOND).retryPolicy(rp).build();
		cfFluent.start();
		System.out.println("Thread [" + thread + "]Server connected...");
		return cfFluent;
	}
}

Thread [1]Server connected...
Thread [2]Server connected...
Thread [0]Server connected...
Thread [0]Do some business work...timestamp [1484621709106] times [1]
Thread [1]Do some business work...timestamp [1484621710198] times [2]
Thread [2]Do some business work...timestamp [1484621711329] times [3]
Thread [0]Do some business work...timestamp [1484621712396] times [4]
Thread [1]Do some business work...timestamp [1484621713438] times [5]
Thread [2]Do some business work...timestamp [1484621714586] times [6]
Thread [0]Do some business work...timestamp [1484621715688] times [7]
Thread [1]Do some business work...timestamp [1484621716725] times [8]

package com.freud.zk.curator;

import java.text.MessageFormat;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.leader.LeaderLatch;
import org.apache.curator.framework.recipes.leader.LeaderLatchListener;
import org.apache.curator.retry.ExponentialBackoffRetry;

/**
 * 
 * Zookeeper - Curator - Leader Latch
 * 
 * @author Freud
 *
 */
public class CuratorLeaderLatchZookeeper {

	private static final int SECOND = 1000;

	public static void main(String[] args) throws Exception {
		ExecutorService service = Executors.newFixedThreadPool(3);
		for (int i = 0; i < 3; i++) {
			final int index = i;
			service.submit(new Runnable() {
				public void run() {
					try {
						new CuratorLeaderLatchZookeeper().schedule(index);
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
			});
		}

		Thread.sleep(10 * SECOND);
		service.shutdownNow();
	}

	private void schedule(final int thread) throws Exception {
		CuratorFramework client = this.getStartedClient(thread);
		String path = "/leader_latch";
		if (client.checkExists().forPath(path) == null) {
			client.create().creatingParentsIfNeeded().forPath(path);
		}

		LeaderLatch latch = new LeaderLatch(client, path);
		latch.addListener(new LeaderLatchListener() {

			public void notLeader() {
				System.out.println(MessageFormat.format("Thread [" + thread
						+ "] I am not the leader... timestamp [{0}]", System.currentTimeMillis()));
			}

			public void isLeader() {
				System.out.println(MessageFormat.format("Thread [" + thread + "] I am the leader... timestamp [{0}]",
						System.currentTimeMillis()));
			}
		});

		latch.start();

		Thread.sleep(2 * (thread + 1) * SECOND);
		if (latch != null) {
			latch.close();
		}
		if (client != null) {
			client.close();
		}
		System.out.println("Thread [" + thread + "] Server closed...");
	}

	private CuratorFramework getStartedClient(final int thread) {
		RetryPolicy rp = new ExponentialBackoffRetry(1 * SECOND, 3);
		// Fluent风格创建
		CuratorFramework cfFluent = CuratorFrameworkFactory.builder().connectString("localhost:2181")
				.sessionTimeoutMs(5 * SECOND).connectionTimeoutMs(3 * SECOND).retryPolicy(rp).build();
		cfFluent.start();
		System.out.println("Thread [" + thread + "] Server connected...");
		return cfFluent;
	}
}

Thread [1] Server connected...
Thread [0] Server connected...
Thread [2] Server connected...
Thread [0] I am the leader... timestamp [1,484,622,048,539]
Thread [0] Server closed...
Thread [1] I am the leader... timestamp [1,484,622,050,431]
Thread [2] I am the leader... timestamp [1,484,622,052,427]
Thread [1] Server closed...
Thread [2] Server closed...