Disruptor 分析

通過分析如下代碼，大致瞭解Disruptor的原理

 1 public static void main(String[] args)throws Exception{
 2         EventFactory<LongEvent> eventFactory = new LongEventFactory();
 3         int ringBufferSize = 1024;
 4         ExecutorService executors = Executors.newCachedThreadPool();
 5         final Disruptor<LongEvent> disruptor = new Disruptor<LongEvent>(eventFactory, ringBufferSize, executors,ProducerType.SINGLE, new BlockingWaitStrategy());    
 6         //final Disruptor<IntEvent> disruptor = new Disruptor<IntEvent>(eventFactory, ringBufferSize, executors,ProducerType.MULTI, new BlockingWaitStrategy()); //多生產者
 7         Consumer consumer1 = new Consumer();
 8         Consumer consumer2 = new Consumer();
 9         EventHandlerGroup<LongEvent> firstLevel = disruptor.handleEventsWith(consumer1,consumer2);
10         Consumer consumer21 = new Consumer();
11         Consumer consumer22 = new Consumer();
12         EventHandlerGroup<LongEvent> secondLevel = firstLevel.then(consumer21,consumer22);
13         disruptor.start();    //啟動disruptor,consumer開始等待，消費數據
14         Producer producer = new Producer(disruptor);
15         
16         //啟動生產者
17         new Thread(producer).start();
18     }

　1.　第2行代碼  EventFactory<LongEvent> eventFactory = new LongEventFactory();

　數據工廠類構造單個數據，disruptor使用此工廠類預分配數據。

　2.　第5行代碼　final Disruptor<LongEvent> disruptor = new Disruptor<LongEvent>(eventFactory, ringBufferSize, executors,ProducerType.SINGLE, new BlockingWaitStrategy());

　預分配數據，構建RingBuffer，指定生產者類型（單生產者、多生產者）、消費者執行的線程池、生產者等待可發佈數據空間和消費者等待可消費數據的策略。

　3.　第9行代碼　EventHandlerGroup<LongEvent> firstLevel = disruptor.handleEventsWith(consumer1,consumer2);

   每個消費者Handler都會被封裝為一個Processor，其可消費序號由其sequence barrier決定。

　4.　第12行代碼 EventHandlerGroup<LongEvent> secondLevel = firstLevel.then(consumer21,consumer22);

　5.　第13行代碼 disruptor.start(); //啟動disruptor,consumer開始等待，消費數據

　6.　第14-17行代碼，創建啟動生產者，發佈數據