disruptor使用示例

LMAX 开源了一个高性能并发编程框架。可以理解为消费者-生产者的消息发布订阅模式。本文下载了官方示例代码，进行实验。

longEvent事件数据

 

public class LongEvent {
    private long value;

    public void set(long value) {
        this.value = value;
    }
    
    public long get(){
        return this.value;
    }
}

 

 

LongEventFactory事件工厂

 

import com.lmax.disruptor.EventFactory;
/**
 * 事件生产工厂
 * @author wanghao
 *
 */
public class LongEventFactory implements EventFactory<LongEvent>
{

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

}

 

 

LongEventProducer事件生产者

import java.nio.ByteBuffer;

import com.lmax.disruptor.RingBuffer;

/**
 * 生产者，生产longEvent事件
 * @author harry
 *
 */
public class LongEventProducer {
	private final RingBuffer<LongEvent> ringBuffer;

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

    public void product(ByteBuffer bb)
    {
        long sequence = ringBuffer.next();  // Grab the next sequence
        try
        {
            LongEvent event = ringBuffer.get(sequence); // Get the entry in the Disruptor
                                                        // for the sequence
            event.set(bb.getLong(0));  // Fill with data
        }
        finally
        {
            ringBuffer.publish(sequence);
        }
    }
}

RingBuffer是消息存储结构，为环形存储结构，每个单元存储一条消息。类似于队列。当ringbuffer中数据填满后，环就会阻塞，等待消费者消费掉数据。当所有消费者消费掉环中一个数据，新的消息才可以加入环中。每个环插入数据后，都会分配下一个位置的编号，即sequence 。

消息者事件处理器

为消费者消费处理器，这处需要执行速度足够快。否则，会影响ringbuffer后续没空间加入新的数据。因此，不能做业务耗时操作。建议另外开始java 线程池处理消息。

 

import com.lmax.disruptor.EventHandler;
/**
 * 消息者事件处理器，打印输出到控制台
 * @author harry
 *
 */
public class LongEventHandler  implements EventHandler<LongEvent>{
	  public void onEvent(LongEvent event, long sequence, boolean endOfBatch)
	    {
	        System.out.println("consumer:"+Thread.currentThread().getName()+" Event: value=" + event.get()+",sequence="+sequence+",endOfBatch="+endOfBatch);
	    }
}

 

LongEventProducerWithTranslator

 

import java.nio.ByteBuffer;

import com.lmax.disruptor.EventTranslatorOneArg;
import com.lmax.disruptor.RingBuffer;

/**
 * post-3.0 the preferred approach for publishing messages is 
 * via the Event Publisher/Event Translator portion of the API. E.g.
 * @author harry
 *
 */
public class LongEventProducerWithTranslator {
	private final RingBuffer<LongEvent> ringBuffer;

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

    private static final EventTranslatorOneArg<LongEvent, ByteBuffer> TRANSLATOR =
        new EventTranslatorOneArg<LongEvent, ByteBuffer>()
        {
            public void translateTo(LongEvent event, long sequence, ByteBuffer bb)
            {
                event.set(bb.getLong(0));
            }
        };

    public void product(ByteBuffer bb)
    {
        ringBuffer.publishEvent(TRANSLATOR, bb);
    }
}

translateTo方法将ringbuffer中的消息，转换成java对象格式。示例 为LongEvent对象，后续消费者LongEventHandler 处理器，直接操作LongEvent对象，获取消息各属性信息，本示例 为value属性。

 

product方法，将生产者生产的消息放入ringbuffer中。

LongEventMain

 

消费者-生产者启动类,其依靠构造Disruptor对象，调用start()方法完成启动线程。Disruptor 需要ringbuffer环，消费者数据处理工厂，WaitStrategy等

ByteBuffer 类字节buffer，用于包装消息。

ProducerType.SINGLE为单线程 ，可以提高性能。

 

import com.lmax.disruptor.dsl.Disruptor;
import com.lmax.disruptor.dsl.ProducerType;
import com.lmax.disruptor.BlockingWaitStrategy;
import com.lmax.disruptor.RingBuffer;
import java.nio.ByteBuffer;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
public class LongEventMain {
	@SuppressWarnings("unchecked")
	public static void main(String[] args) throws Exception
	    {
	        // 执行器，用于构造消费者线程
	        Executor executor = Executors.newCachedThreadPool();

	        // 指定事件工厂
	        LongEventFactory factory = new LongEventFactory();

	        // 指定 ring buffer字节大小, must be power of 2.
	        int bufferSize = 1024;

	        //单线程模式，获取额外的性能
	        Disruptor<LongEvent> disruptor = new Disruptor<LongEvent>(factory, 
                    bufferSize,executor,
                    ProducerType.SINGLE,
                    new BlockingWaitStrategy());
	        //设置事件业务处理器---消费者
	        disruptor.handleEventsWith(new LongEventHandler());
	        //启动disruptor线程
	        disruptor.start();

	        // 获取 ring buffer环，用于接取生产者生产的事件
	        RingBuffer<LongEvent> ringBuffer = disruptor.getRingBuffer();
	        //为 ring buffer指定事件生产者
	        //LongEventProducer producer = new LongEventProducer(ringBuffer);
	        LongEventProducerWithTranslator producer=new LongEventProducerWithTranslator(ringBuffer);
	        ByteBuffer bb = ByteBuffer.allocate(8);//预置8字节长整型字节缓存
	        for (long l = 0; true; l++)
	        {
	            bb.putLong(0, l);
	            producer.product(bb);//生产者生产数据
	            Thread.sleep(1000);
	        }
	        
	    }
}

 

 

实验结果：

consumer:pool-1-thread-1 Event: value=0,sequence=0,endOfBatch=true
consumer:pool-1-thread-1 Event: value=1,sequence=1,endOfBatch=true
consumer:pool-1-thread-1 Event: value=2,sequence=2,endOfBatch=true
consumer:pool-1-thread-1 Event: value=3,sequence=3,endOfBatch=true
consumer:pool-1-thread-1 Event: value=4,sequence=4,endOfBatch=true
consumer:pool-1-thread-1 Event: value=5,sequence=5,endOfBatch=true
consumer:pool-1-thread-1 Event: value=6,sequence=6,endOfBatch=true

 

Event: value = 为消费者接收到的数据，sequence为数据在ringbuffer环的位置。

 

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