Java深入学习（6）：Disruptor

Disruptor框架简介：

并发框架，基于事件驱动，使用观察者模式

底层采用环形数组，取模算法

简单使用：

/**
 * 声明一个Event：表示生产者和消费者之间传递的数据类型
 */
public class LongEvent {

    private Long value;

    public Long getValue() {
        return value;
    }

    public void setValue(Long value) {
        this.value = value;
    }

}

工厂：

/**
 * 实例化
 */
public class LongEventFactory implements EventFactory<LongEvent> {

    public LongEvent newInstance() {
        return new LongEvent();
    }

}

消费者：

/**
 * 消费者
 */
public class LongEventHandler implements EventHandler<LongEvent> {

    public void onEvent(LongEvent event, long sequence, boolean endOfBatch) throws Exception {
        System.out.println("消费者获取数据:"+event.getValue());
    }

}

生产者：

/**
 * 生产者
 */
public class LongEventProducer {

    private RingBuffer<LongEvent> ringBuffer;

    public LongEventProducer(RingBuffer<LongEvent> ringBuffer) {
        this.ringBuffer = ringBuffer;
    }

    public void onData(ByteBuffer byteBuffer) {
        //获取事件队列的下标位置
        long sequence = ringBuffer.next();
        try {
            //取出空队列
            LongEvent longEvent = ringBuffer.get(sequence);
            //给空队列赋值
            longEvent.setValue(byteBuffer.getLong(0));
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            System.out.println("生产者发送数据");
            //发送数据
            ringBuffer.publish(sequence);
        }
    }

}

启动：

public class Main {

    public static void main(String[] args) {
        //创建可缓存线程池
        ExecutorService executor = Executors.newCachedThreadPool();
        //创建工厂
        EventFactory<LongEvent> factory = new LongEventFactory();
        //创建RingBuffer（必须为2的N次方）
        int ringBuffer = 1024 * 1024;
        //创建Disruptor
        Disruptor<LongEvent> disruptor = new Disruptor<LongEvent>(
                factory,
                ringBuffer,
                executor,
                ProducerType.MULTI,
                new YieldingWaitStrategy()
        );
        //注册消费者（如果注册多个消费者默认是重复消费）
        disruptor.handleEventsWith(new LongEventHandler());
        //启动
        disruptor.start();
        //创建RingBuffer容器
        RingBuffer<LongEvent> buffer = disruptor.getRingBuffer();
        //创建生产者
        LongEventProducer longEventProducer = new LongEventProducer(buffer);
        //定义大小为8的缓冲区
        ByteBuffer byteBuffer = ByteBuffer.allocate(8);
        for (int i = 0; i < 100; i++) {
            byteBuffer.putLong(0, i);
            longEventProducer.onData(byteBuffer);
        }
        executor.shutdown();
        disruptor.shutdown();
    }

}

打印如下：

....................
消费者获取数据:39
生产者发送数据
消费者获取数据:40
生产者发送数据
消费者获取数据:41
生产者发送数据
消费者获取数据:42
....................