并发框架Disruptor几个Demo

声明：转自http://xsh5324.iteye.com/blog/2058925?utm_source=tool.lu

扫盲：

要想了解Disruptor框架必需多花点时间研究下它的工作原理，不然代码是没法撸的！！！

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

 

Disruptor版本： 3.2.1

 

名词解释

消费者==事件处理器

 

 

一、现在你必须明白以下问题：

1、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，为什么高效，它的职责是什么。

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

 

Disruptor框架在2.0版本之后不再采用生产者、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，内部原理其实还是一样的。

 

DEMO 一、使用原生API创建一个简单的生产者和消费者

 

 //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 {
         //这里做具体的消费逻辑
         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创建一个单生产者的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&运算提高效率
          * 第三个参数是RingBuffer的生产都在没有可用区块的时候(可能是消费者（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());
         //创建线程池
         ExecutorService executors = Executors.newFixedThreadPool(THREAD_NUMBERS);
         //创建SequenceBarrier
         SequenceBarrier sequenceBarrier = ringBuffer.newBarrier();

         //创建消息处理器
         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    如果只有一个消费者的情况可以省略
         ringBuffer.addGatingSequences(transProcessor.getSequence());

         //把消息处理器提交到线程池
         executors.submit(transProcessor);
         //如果存大多个消费者 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  如果此处不理解，想想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 可以结束了（并不是马上结束!!!）
         executors.shutdown();//终止线程
     }
 }

 

 DEMO二、使用WorkerPool辅助创建消费者

 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，亲自己看哈！~
          */
         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();
     }
 }

 DEMO三、demo3写个流弊点的像下图这样。这次用Disruptor来完成整个构建工作.

从中图可以看出需求是介样子的：生产者生产数据经过C1,C2处理完成后再到C3。

假设如下场景：

1、交易网关收到交易(P1)把交易数据发到RingBuffer中，

2、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

3、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：

 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之后就看下就明白了，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创建消费者组C1,C2
         EventHandlerGroup<TradeTransaction> handlerGroup=disruptor.handleEventsWith(new TradeTransactionVasConsumer(),new TradeTransactionInDBHandler());

         TradeTransactionJMSNotifyHandler jmsConsumer=new TradeTransactionJMSNotifyHandler();
         //声明在C1,C2完事之后执行JMS消息发送操作 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));
     }
 }