高并发线程内存事件处理器 disruptor 二 hello world

本篇为disruptor的一个demo，帮助大家快速入门使用起来，下面的代码是一个简单的实现，可以跟着本地debug进行源码查看一下具体的事件处理过程

先了解一下步骤：

1. 建立一个Event类
2. 建立一个工厂Event类，用于创建Event类实例对象
3. 需要有一个监听事件类，用于处理数据（Event类）
4. 我们需要进行测试代码编写。实例化Disruptor实例，配置参数。然后我们对Disruptor实例绑定监听事件类，接受并处理数据。
5. 在Disruptor中，真正存储数据的核心叫做RingBuffer，我们通过Disruptor实例拿到它，然后把数据生产出来，把数据加入到RingBuffer的实例对象中即可

package com.lxj.disruptor;
 
/*
 * 用于传递数据的对象
 */
public class StringEvent {
 
	private Integer id;
	private String value;
 
	public Integer getId() {
		return id;
	}
 
	public void setId(Integer id) {
		this.id = id;
	}
 
	public String getValue() {
		return value;
	}
 
	public void setValue(String value) {
		this.value = value;
	}
 
	@Override
	public String toString() {
		return "StringEvent [id=" + id + ", value=" + value + "]";
	}
 
}

package com.lxj.disruptor;
 
import com.lmax.disruptor.EventFactory;
 
/*
 * 实现Disruptor提供的工厂接口，工厂方法模式
 */
public class StringEventFactory implements EventFactory<StringEvent> {
 
	@Override
	public StringEvent newInstance() {
		//我们自定义的对象
		return new StringEvent();
	}
 
}

package com.lxj.disruptor;
 
import com.lmax.disruptor.EventHandler;
 
/*
 * 事件的处理器，也就是消费者，这里模拟的是将数据打印处理
 */
public class StringEventHandler implements EventHandler<StringEvent> {
 
	@Override
	public void onEvent(StringEvent stringEvent, long sequence, boolean bool) throws Exception {
		System.out.println("StringEventHandler(消费者):  "  + stringEvent +", sequence= "+sequence+",bool="+bool);    
	}
 
}

package com.lxj.disruptor;
 
import java.nio.ByteBuffer;
 
import com.lmax.disruptor.RingBuffer;
 
/*
 * 这是一个事件源，模拟的就是网络或者磁盘IO发送数据过来，触发事件
 * ByteBuffer中携带着数据
 */
public class StringEventProducer {
     
	private final RingBuffer<StringEvent> ringBuffer;
 
	public StringEventProducer(RingBuffer<StringEvent> ringBuffer) {
	     this.ringBuffer = ringBuffer;
	}
	 
	
	public void sendData(ByteBuffer byteBuffer) {
        //ringBuffer就是用来存储数据的，具体可以看disruptor源码的数据结构，next就是获取下一个空事件索引
		long sequence = ringBuffer.next();
		try {
			//通过索引获取空事件 
			StringEvent stringEvent = ringBuffer.get(sequence);
			//切换成读模式
			byteBuffer.flip();
			//从byteBuffer中读取传过来的值
			byte[] dst = new byte[byteBuffer.limit()];
			byteBuffer.get(dst, 0, dst.length);
			//为stringEvent赋值，填充数据
			stringEvent.setValue(new String(dst));
			stringEvent.setId((int) sequence);
			//clear一下缓冲区
			byteBuffer.clear();
		} finally {
			//发布事件，为确保安全，放入finally中，不会造成disruptor的混乱
			ringBuffer.publish(sequence);
		}
	}
	 
}

package com.lxj.disruptor;
 
import java.nio.ByteBuffer;
 
import com.lmax.disruptor.EventTranslatorOneArg;
import com.lmax.disruptor.RingBuffer;
 
/*
 * 一个Translator可以看做一个事件初始化器
 */
public class StringEventProducerWithTranslator {
 
	private final RingBuffer<StringEvent> ringBuffer;
	
	//填充数据
	public static final EventTranslatorOneArg<StringEvent, ByteBuffer> TRANSLATOR = new EventTranslatorOneArg<StringEvent, ByteBuffer>() {
		@Override
		public void translateTo(StringEvent stringEvent, long sequence, ByteBuffer byteBuffer) {
			// 从byteBuffer中读取传过来的值
			byteBuffer.flip();
			byte[] dst = new byte[byteBuffer.limit()];
			byteBuffer.get(dst, 0, dst.length);
			byteBuffer.clear();
			// 为stringEvent赋值，填充数据
			stringEvent.setValue(new String(dst));
			stringEvent.setId((int) sequence);
		}
	};
	
	public StringEventProducerWithTranslator( RingBuffer<StringEvent> ringBuffer) {
		this.ringBuffer = ringBuffer;
	}
	
	//发布事件 
   	public void sendData(ByteBuffer byteBuffer) {
		ringBuffer.publishEvent(TRANSLATOR, byteBuffer);
	}
	
	
 
}

package com.lxj.disruptor;
 
import java.nio.ByteBuffer;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Lock;
 
import com.lmax.disruptor.RingBuffer;
import com.lmax.disruptor.YieldingWaitStrategy;
import com.lmax.disruptor.dsl.Disruptor;
import com.lmax.disruptor.dsl.ProducerType;
 
/*
 * 测试主函数
 */
public class StringEventMain {
 
	public static void main(String[] args) throws Exception {
        //创建一个线程池
		ExecutorService executorPool = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
		//创建Event工厂
		StringEventFactory factory = new StringEventFactory();
		/*
		 *	  创建Disruptor对象
		 *   eventFactory, 传入实现了EventFactory借口的工厂类
		 *   ringBufferSize, 用来存储数据的， 值为 2^n  
		 *   executor, 线程池 
		 *   producerType, 类型，可以是多个生产者，也可以是单个生产者 
		 *   waitStrategy, 使用什么策略，消费者如何等待生产者放入disruptor中 :
				     BlockingWaitStrategy 是最低效的策略，但其对CPU的消耗最小并且在各种不同部署环境中能提供更加一致的性能表现
					 SleepingWaitStrategy 的性能表现跟BlockingWaitStrategy差不多，对CPU的消耗也类似，但其对生产者线程的影响最小，适合用于异步日志类似的场景
					 YieldingWaitStrategy 的性能是最好的，适合用于低延迟的系统。在要求极高性能且事件处理线数小于CPU逻辑核心数的场景中，推荐使用此策略；例如，CPU开启超线程的特性
		 */
		Disruptor<StringEvent> disruptor = new Disruptor<>(factory, (int)Math.pow(2, 20), executorPool, ProducerType.SINGLE, new YieldingWaitStrategy());
		//关联处理器，也就是消费者，连接消费事件方法
		disruptor.handleEventsWith(new StringEventHandler());
		//启动
		disruptor.start();
		//获取RingBuffer,模拟生产者发布消息
		RingBuffer<StringEvent> ringBuffer = disruptor.getRingBuffer();
		
		StringEventProducerWithTranslator producer = new StringEventProducerWithTranslator(ringBuffer);
		//StringEventProducer producer = new StringEventProducer(ringBuffer);
		ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
		
		//闭锁控制线程同步
		CountDownLatch countDownLatch = new CountDownLatch(1);
		new Thread(new Runnable() {
			@Override
			public void run() {
				for(int i = 0 ; i < 10 ; i ++) {
					//下面是进行触发事件并且发布
					byteBuffer.put(new String("生产者"+ i +"发布消息").getBytes());
					producer.sendData(byteBuffer);
					//模拟进行其他操作的耗时
					try {
						Thread.sleep(1000);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
				countDownLatch.countDown();
			}
		},"Thread2").start();;
		//等待
		countDownLatch.await();
		disruptor.shutdown(); //关闭 disruptor
		executorPool.shutdown(); //关闭线程池
	}
 
}