前段时间闲得蛋疼就尝试翻译了一下有关Disruptor的一些文章,第一次做这事,烂得自己也不忍回头去看了。。。
今天写日志看到那几篇文章,于是想写一个简单的例子,好让一些对Disruptor有兴趣但不是很明白的人更快的了解Disruptor的基本用法。
Disruptor使用起来非常简单,初始化->启动消费者线程,然后每当生产者产生资源就往disruptor里放。
下面是一个接收短信状态报告的例子。
首先自定义一个Event类:
1 public class DeliveryReportEvent { 2 private DeliveryReport deliveryReport; 3 4 public DeliveryReport getDeliveryReport() { 5 return deliveryReport; 6 } 7 8 public void setDeliveryReport(DeliveryReport deliveryReport) { 9 this.deliveryReport = deliveryReport; 10 } 11 12 13 public final static EventFactory<DeliveryReportEvent> EVENT_FACTORY = new EventFactory<DeliveryReportEvent>() { 14 public DeliveryReportEvent newInstance() { 15 return new DeliveryReportEvent(); 16 } 17 }; 18 }
代码很简单,就是用来存放短信状态报告DeliveryReport类的,外加一个EventFactory,用来生成Event,也很简单。
然后写一个EventHandler类,用来处理Event,
1 public class DeliveryReportEventHandler implements EventHandler<DeliveryReportEvent> { 2 // private static DeliveryReportRepository repository = new DeliveryReportRepository(); 3 public void onEvent(DeliveryReportEvent event, long sequence, 4 boolean endOfBatch) throws Exception { 5 System.out.println(event.getDeliveryReport().getMessageId()); 6 // repository.updateDeliveryReport(event.getDeliveryReport()); 7 } 8 }
三个参数,event就是生产者向Disruptor发布资源生产的事件,sequence是这个事件在ringbuffer中的序列号,endOfBatch指明该事件是不是ringbuffer中的最后一个事件。
在onEvent方法里处理消费者要做的事。本例直接打印状态报告ID或是更新数据库中的状态报告。
在这里我写了一个辅助类:
1 public class DisruptorHelper { 2 /** 3 * ringbuffer容量,最好是2的N次方 4 */ 5 private static final int BUFFER_SIZE = 1024 * 8; 6 private RingBuffer<DeliveryReportEvent> ringBuffer; 7 private SequenceBarrier sequenceBarrier; 8 private DeliveryReportEventHandler handler; 9 private BatchEventProcessor<DeliveryReportEvent> batchEventProcessor; 10 private static DisruptorHelper instance; 11 private static boolean inited = false; 12 private DisruptorHelper(){ 13 ringBuffer = new RingBuffer<DeliveryReportEvent>( 14 DeliveryReportEvent.EVENT_FACTORY, new SingleThreadedClaimStrategy( 15 BUFFER_SIZE), new YieldingWaitStrategy()); 16 sequenceBarrier = ringBuffer.newBarrier(); 17 handler = new DeliveryReportEventHandler(); 18 batchEventProcessor = new BatchEventProcessor<DeliveryReportEvent>( 19 ringBuffer, sequenceBarrier, handler); 20 ringBuffer.setGatingSequences(batchEventProcessor 21 .getSequence()); 22 } 23 24 public static void initAndStart(){ 25 instance = new DisruptorHelper(); 26 new Thread(instance.batchEventProcessor).start(); 27 inited = true; 28 } 29 30 public static void shutdown(){ 31 if(!inited){ 32 throw new RuntimeException("Disruptor还没有初始化!"); 33 } 34 instance.shutdown0(); 35 } 36 37 private void shutdown0(){ 38 batchEventProcessor.halt(); 39 } 40 private void produce0(DeliveryReport deliveryReport) { 41 //获取下一个序列号 42 long sequence = ringBuffer.next(); 43 //将状态报告存入ringBuffer的该序列号中 44 ringBuffer.get(sequence).setDeliveryReport(deliveryReport); 45 //通知消费者该资源可以消费 46 ringBuffer.publish(sequence); 47 } 48 49 /** 50 * 将状态报告放入资源队列,等待处理 51 * @param deliveryReport 52 */ 53 public static void produce(DeliveryReport deliveryReport) { 54 if(!inited){ 55 throw new RuntimeException("Disruptor还没有初始化!"); 56 } 57 instance.produce0(deliveryReport); 58 } 59 }
哈哈,因为本例的initAndStart/shutdown方法是在一个loadonstartup的servlet中的init/destory方法里调用,所以就不加synchronized了,执行前也不判断inited是否为true了。
最后是生产者调用的方法,在接收短信状态报告的webservice里:
1 public void NotifySmsDeliveryReport(DeliveryReport deliveryReport) { 2 ... 3 ... 4 //向disruptor发布资源 5 DisruptorHelper.produce(deliveryReport); 6 }
关于disruptor的性能,可以去官网查看测试数据。也可以从官方svn检出代码,自己运行一下src/perf里的性能测试方法,
本例用到的包只有一个disruptor-2.7.1.jar,
<dependency>
<groupId>com.googlecode.disruptor</groupId>
<artifactId>disruptor</artifactId>
<version>2.7.1</version>
</dependency>