并发框架Disruptor几个Demo

时间 2019-11-08

标签并发框架 disruptor 几个 demo 繁體版

原文原文链接

扫盲：

要想了解Disruptor框架必需多花点时间研究下它的工做原理，否则代码是无法撸的！！！数据结构

关于Disruptor的详细资料及原理请细看!!! http://ifeve.com/disruptor/ 框架

Disruptor版本： 3.2.1

名词解释

消费者==事件处理器 dom

1、如今你必须明白如下问题：

一、你必须明白Ringbuffer是什么，它的数据结构是怎么样的，有什么约定，为何高效，它的职责是什么。 ide

二、ConsumerBarrier （ifeve网上的译文版本比较早，这个类在2.0.0以后就一直被更名，3.2.1的版本中它是SequenceBarrier）它的职责是什么。函数

Disruptor框架在2.0版本以后再也不采用生产者、消费者模型来编写API，而是使用事件模型，其实只是接口设计、类名和概念上的变化，内部原理其实仍是同样的。 this

DEMO 1、使用原生API建立一个简单的生产者和消费者

Java代码

//DEMO中使用的消息全假定是一条交易
public class TradeTransaction {
private String id;//交易ID
private double price;//交易金额
public TradeTransaction() {
}
public TradeTransaction(String id, double price) {
super();
this.id = id;
this.price = price;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
}
public class TradeTransactionInDBHandler implements EventHandler<TradeTransaction>,WorkHandler<TradeTransaction> {
@Override
public void onEvent(TradeTransaction event, long sequence,
boolean endOfBatch) throws Exception {
this.onEvent(event);
}
@Override
public void onEvent(TradeTransaction event) throws Exception {
//这里作具体的消费逻辑
event.setId(UUID.randomUUID().toString());//简单生成下ID
System.out.println(event.getId());
}
}
public class Demo1 {
public static void main(String[] args) throws InterruptedException, ExecutionException {
int BUFFER_SIZE=1024;
int THREAD_NUMBERS=4;
/*
* createSingleProducer建立一个单生产者的RingBuffer，
* 第一个参数叫EventFactory，从名字上理解就是“事件工厂”，其实它的职责就是产生数据填充RingBuffer的区块。
* 第二个参数是RingBuffer的大小，它必须是2的指数倍目的是为了将求模运算转为&运算提升效率
* 第三个参数是RingBuffer的生产都在没有可用区块的时候(多是消费者（或者说是事件处理器）太慢了)的等待策略
*/
final RingBuffer<TradeTransaction> ringBuffer = RingBuffer.createSingleProducer(new EventFactory<TradeTransaction>() {
@Override
public TradeTransaction newInstance() {
return new TradeTransaction();
}
}, BUFFER_SIZE,new YieldingWaitStrategy());
//建立线程池
ExecutorService executors = Executors.newFixedThreadPool(THREAD_NUMBERS);
//建立SequenceBarrier
SequenceBarrier sequenceBarrier = ringBuffer.newBarrier();
//建立消息处理器
BatchEventProcessor<TradeTransaction> transProcessor = new BatchEventProcessor<TradeTransaction>(
ringBuffer, sequenceBarrier, new TradeTransactionInDBHandler());
//这一部的目的是让RingBuffer根据消费者的状态若是只有一个消费者的状况能够省略
ringBuffer.addGatingSequences(transProcessor.getSequence());
//把消息处理器提交到线程池
executors.submit(transProcessor);
//若是存大多个消费者那重复执行上面3行代码把TradeTransactionInDBHandler换成其它消费者类
Future<?> future=executors.submit(new Callable<Void>() {
@Override
public Void call() throws Exception {
long seq;
for(int i=0;i<1000;i++){
seq=ringBuffer.next();//占个坑 --ringBuffer一个可用区块
ringBuffer.get(seq).setPrice(Math.random()*9999);//给这个区块放入数据若是此处不理解，想一想RingBuffer的结构图
ringBuffer.publish(seq);//发布这个区块的数据使handler(consumer)可见
}
return null;
}
});
future.get();//等待生产者结束
Thread.sleep(1000);//等上1秒，等消费都处理完成
transProcessor.halt();//通知事件(或者说消息)处理器能够结束了（并非立刻结束!!!）
executors.shutdown();//终止线程
}
}

DEMO2、使用WorkerPool辅助建立消费者

Java代码

public class Demo2 {
public static void main(String[] args) throws InterruptedException {
int BUFFER_SIZE=1024;
int THREAD_NUMBERS=4;
EventFactory<TradeTransaction> eventFactory=new EventFactory<TradeTransaction>() {
public TradeTransaction newInstance() {
return new TradeTransaction();
}
};
RingBuffer<TradeTransaction> ringBuffer=RingBuffer.createSingleProducer(eventFactory, BUFFER_SIZE);
SequenceBarrier sequenceBarrier = ringBuffer.newBarrier();
ExecutorService executor = Executors.newFixedThreadPool(THREAD_NUMBERS);
WorkHandler<TradeTransaction> workHandlers=new TradeTransactionInDBHandler();
/*
* 这个类代码很简单的，亲本身看哈！~
*/
WorkerPool<TradeTransaction> workerPool=new WorkerPool<TradeTransaction>(ringBuffer, sequenceBarrier, new IgnoreExceptionHandler(), workHandlers);
workerPool.start(executor);
//下面这个生产8个数据，图简单就写到主线程算了
for(int i=0;i<8;i++){
long seq=ringBuffer.next();
ringBuffer.get(seq).setPrice(Math.random()*9999);
ringBuffer.publish(seq);
}
Thread.sleep(1000);
workerPool.halt();
executor.shutdown();
}
}

DEMO3、demo3写个流弊点的像下图这样。此次用Disruptor来完成整个构建工做.

从中图能够看出需求是介样子的：生产者生产数据通过C1,C2处理完成后再到C3。 spa

假设以下场景：线程

一、交易网关收到交易(P1)把交易数据发到RingBuffer中，设计

二、负责处理增值业务的消费者C1和负责数据存储的消费者C2负责处理交易接口

三、负责发送JMS消息的消费者C3在C1和C2处理完成后再进行处理。

让代码说话：

Java代码

public class TradeTransactionJMSNotifyHandler implements EventHandler<TradeTransaction> {
@Override
public void onEvent(TradeTransaction event, long sequence,
boolean endOfBatch) throws Exception {
//do send jms message
}
}
public class TradeTransactionPublisher implements Runnable{
Disruptor<TradeTransaction> disruptor;
private CountDownLatch latch;
private static int LOOP=10000000;//模拟一千万次交易的发生
public TradeTransactionPublisher(CountDownLatch latch,Disruptor<TradeTransaction> disruptor) {
this.disruptor=disruptor;
this.latch=latch;
}
@Override
public void run() {
TradeTransactionEventTranslator tradeTransloator=new TradeTransactionEventTranslator();
for(int i=0;i<LOOP;i++){
disruptor.publishEvent(tradeTransloator);
}
latch.countDown();
}
}
class TradeTransactionEventTranslator implements EventTranslator<TradeTransaction>{
private Random random=new Random();
@Override
public void translateTo(TradeTransaction event, long sequence) {
this.generateTradeTransaction(event);
}
private TradeTransaction generateTradeTransaction(TradeTransaction trade){
trade.setPrice(random.nextDouble()*9999);
return trade;
}
}
public class TradeTransactionVasConsumer implements EventHandler<TradeTransaction> {
@Override
public void onEvent(TradeTransaction event, long sequence,
boolean endOfBatch) throws Exception {
//do something....
}
}
public class Demo3 {
public static void main(String[] args) throws InterruptedException {
long beginTime=System.currentTimeMillis();
int bufferSize=1024;
ExecutorService executor=Executors.newFixedThreadPool(4);
//这个构造函数参数，相信你在了解上面2个demo以后就看下就明白了，不解释了~
Disruptor<TradeTransaction> disruptor=new Disruptor<TradeTransaction>(new EventFactory<TradeTransaction>() {
@Override
public TradeTransaction newInstance() {
return new TradeTransaction();
}
}, bufferSize, executor, ProducerType.SINGLE, new BusySpinWaitStrategy());
//使用disruptor建立消费者组C1,C2
EventHandlerGroup<TradeTransaction> handlerGroup=disruptor.handleEventsWith(new TradeTransactionVasConsumer(),new TradeTransactionInDBHandler());
TradeTransactionJMSNotifyHandler jmsConsumer=new TradeTransactionJMSNotifyHandler();
//声明在C1,C2完事以后执行JMS消息发送操做也就是流程走到C3
handlerGroup.then(jmsConsumer);
disruptor.start();//启动
CountDownLatch latch=new CountDownLatch(1);
//生产者准备
executor.submit(new TradeTransactionPublisher(latch, disruptor));
latch.await();//等待生产者完事.
disruptor.shutdown();
executor.shutdown();
System.out.println("总耗时:"+(System.currentTimeMillis()-beginTime));
}
}