How to implement a High performance queue in Disruptor

Disruptor中怎么实现一个高性能队列，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。

Disruptor 例子import java.util.concurrent.ThreadFactoryimport com.lmax.disruptor.dsl.{Disruptor, ProducerType}import com.lmax.disruptor.{BlockingWaitStrategy,EventFactory,EventHandler,EventTranslatorOneArg,WaitStrategy}object DisruptorTest { val disruptor = { val factory = new EventFactory[Event] { override def newInstance(): Event = Event(-1) } val threadFactory = new ThreadFactory(){ override def newThread(r: Runnable): Thread = new Thread(r) } val disruptor = new Disruptor[Event](factory, 4, threadFactory, ProducerType.SINGLE, new BlockingWaitStrategy()) disruptor.handleEventsWith(TestHandler).`then`(ThenHandler) disruptor } val translator = new EventTranslatorOneArg[Event, Int]() { override def translateTo(event: Event, sequence: Long, arg: Int): Unit = { event.id = arg println(s"translator: ${event}, sequence: ${sequence}, arg: ${arg}") } } def main(args: Array[String]): Unit = { disruptor.start() (0 until 100).foreach { i => disruptor.publishEvent(translator, i) } disruptor.shutdown() }}case class Event(var id: Int) { override def toString: String = s"event: ${id}"}object TestHandler extends EventHandler[Event] { override def onEvent(event: Event, sequence: Long, endOfBatch: Boolean): Unit = { println(s"${this.getClass.getSimpleName} ${System.nanoTime()} ${event}") }}object ThenHandler extends EventHandler[Event] { override def onEvent(event: Event, sequence: Long, endOfBatch: Boolean): Unit = { println(s"${this.getClass.getSimpleName} ${System.nanoTime()} ${event}") }}源码阅读disrutpor 初始化

先看 Disruptor 构造方法

public Disruptor(final EventFactory eventFactory, final int ringBufferSize, final ThreadFactory threadFactory, final ProducerType producerType, final WaitStrategy waitStrategy) { this(RingBuffer.create(producerType, eventFactory, ringBufferSize, waitStrategy), new BasicExecutor(threadFactory));}

在看 RingBuffer.create, 最终通过 fill 方法 将 eventFactory.newInstance() 作为默认值，塞到 ringBuffer 里面

public static RingBuffer create(ProducerType producerType, EventFactory factory, int bufferSize, WaitStrategy waitStrategy) { switch (producerType) { case SINGLE: return createSingleProducer(factory, bufferSize, waitStrategy); case MULTI: return createMultiProducer(factory, bufferSize, waitStrategy); default: throw new IllegalStateException(producerType.toString()); }}public static RingBuffer createSingleProducer(EventFactory factory, int bufferSize, WaitStrategy waitStrategy) { SingleProducerSequencer sequencer = new SingleProducerSequencer(bufferSize, waitStrategy); return new RingBuffer(factory, sequencer);}RingBufferFields(EventFactory eventFactory, Sequencer sequencer) { this.sequencer = sequencer; this.bufferSize = sequencer.getBufferSize(); if (bufferSize < 1) { throw new IllegalArgumentException("bufferSize must not be less than 1"); } if (Integer.bitCount(bufferSize) != 1) { throw new IllegalArgumentException("bufferSize must be a power of 2"); } this.indexMask = bufferSize - 1; this.entries = new Object[sequencer.getBufferSize() + 2 * BUFFER_PAD]; fill(eventFactory);}private void fill(EventFactory eventFactory) { for (int i = 0; i < bufferSize; i++) { entries[BUFFER_PAD + i] = eventFactory.newInstance(); }}消费事件消息

首先看 disruptor.start(): 消费事件消息入口

private final ConsumerRepository consumerRepository = new ConsumerRepository();public RingBuffer start() { checkOnlyStartedOnce(); for (final ConsumerInfo consumerInfo : consumerRepository) { consumerInfo.start(executor); } return ringBuffer;}

consumerRepository 类型由 disruptor.handleEventsWith(TestHandler) 初始化, 并构造事件消息处理链

public final EventHandlerGroup handleEventsWith(final EventHandler