disruptor入门

1.disruptor是什么？

disruptor是一个高性能的异步处理框架，或者可以认为是最快的消息框架（轻量的JMS），也可以认为是一个观察者模式的实现，或者事件监听模式的实现。

2.disruptor的原理

英文：http://stackoverflow.com/questions/6559308/how-does-lmaxs-disruptor-pattern-work

翻译：http://www.cnblogs.com/adaikiss/archive/2012/02/15/2352545.html

3.实现例子

1）pojo类

/**
 * just think of a pojo
 * @author guolei
 *
 */
public final class ValueEvent
{
    private long value;

    public long getValue()
    {
        return value;
    }

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

    public final static EventFactory<ValueEvent> EVENT_FACTORY = new EventFactory<ValueEvent>()
    {
        public ValueEvent newInstance()
        {
            return new ValueEvent();
        }
    };
}

2）生产者

public class Producer implements Runnable {

	private RingBuffer<ValueEvent> ringBuffer = null;

	public Producer(RingBuffer<ValueEvent> rb) {

		ringBuffer = rb;
	}

	@Override
	public void run() {
		// Publishers claim events in sequence
		long sequence = ringBuffer.next();
		ValueEvent event = ringBuffer.get(sequence);
		event.setValue(1234); // this could be more complex with multiple fields
		
		// make the event available to EventProcessors
		ringBuffer.publish(sequence);   
	}
}

3）消费者

public class ConsumeEventHandler implements EventHandler<ValueEvent>{
	@Override
	public void onEvent(ValueEvent event, long sequence, boolean endOfBatch) throws Exception {
		// TODO Auto-generated method stub
		System.out.println("=================="+event.getValue());
	}

}

4）测试类

public class TestShow {

	private static final int BUFFER_SIZE = 16;

	private final RingBuffer<ValueEvent> ringBuffer = new RingBuffer<ValueEvent>(
			ValueEvent.EVENT_FACTORY, new SingleThreadedClaimStrategy(BUFFER_SIZE),
			new YieldingWaitStrategy());
	private final SequenceBarrier sequenceBarrier = ringBuffer.newBarrier();

	private final ConsumeEventHandler handler = new ConsumeEventHandler();

	private final ExecutorService EXECUTOR = Executors.newSingleThreadExecutor();

	private final BatchEventProcessor<ValueEvent> batchEventProcessor = new BatchEventProcessor<ValueEvent>(
			ringBuffer, sequenceBarrier, handler);

	public TestShow() {
		ringBuffer.setGatingSequences(batchEventProcessor.getSequence());
	}

	public void consume() {
		EXECUTOR.submit(batchEventProcessor);
	}

	public void produce() {
		new Thread(new Producer(ringBuffer)).start();
	}

	public static void main(String[] args) {

		TestShow test = new TestShow();
		test.produce();
		test.consume();
	}
}