Disruptor 常见使用场景与代码示例

1. 引言

上期介绍到Disruptor 是一个高性能的无锁并发队列，适用于需要极低延迟和高吞吐量的应用场景。它通过环形缓冲区（RingBuffer）和高效的事件处理机制，显著减少了 CPU 缓存失效和上下文切换的开销。

今天介绍 Disruptor 的几个常见使用场景：事件处理、日志记录、消息传递、实时数据分析和并发任务调度，让你进一步加深对它的印象，下期将介绍Disruptor核心原理。

2. 典型使用场景

2.1. 事件处理

Disruptor 适用于事件驱动架构，实现高效的事件处理。

示例代码：

public class EventData {
    private String data;
    public void setData(String data) { this.data = data; }
    public String getData() { return data; }
}

public class EventFactory implements EventFactory {
    @Override
    public EventData newInstance() { return new EventData(); }
}

public class EventHandler implements EventHandler {
    @Override
    public void onEvent(EventData event, long sequence, boolean endOfBatch) {
        System.out.println("Processing event: " + event.getData());
    }
}

public class EventProcessingSystem {
    public static void main(String[] args) {
        Disruptor disruptor = new Disruptor<>(
                new EventFactory(),
                1024,
                Executors.defaultThreadFactory(),
                ProducerType.SINGLE,
                new SleepingWaitStrategy()
        );
        
        disruptor.handleEventsWith(new EventHandler());
        disruptor.start();
        
        RingBuffer ringBuffer = disruptor.getRingBuffer();
        ringBuffer.publishEvent((event, sequence) -> event.setData("Sample Event"));
    }
}

2.2. 日志记录

Disruptor 适合用作高性能日志队列，避免传统阻塞队列的性能瓶颈。

示例代码：

public class LogEvent {
    private String message;
    public void setMessage(String message) { this.message = message; }
    public String getMessage() { return message; }
}

public class LogEventFactory implements EventFactory {
    @Override
    public LogEvent newInstance() { return new LogEvent(); }
}

public class LogEventHandler implements EventHandler {
    @Override
    public void onEvent(LogEvent event, long sequence, boolean endOfBatch) {
        System.out.println("Log: " + event.getMessage());
    }
}

public class DisruptorLogSystem {
    public static void main(String[] args) {
        Disruptor disruptor = new Disruptor<>(
                new LogEventFactory(),
                1024,
                Executors.defaultThreadFactory(),
                ProducerType.SINGLE,
                new SleepingWaitStrategy()
        );
        
        disruptor.handleEventsWith(new LogEventHandler());
        disruptor.start();
        
        RingBuffer ringBuffer = disruptor.getRingBuffer();
        ringBuffer.publishEvent((event, sequence) -> event.setMessage("Test Log"));
    }
}

2.3. 消息传递

Disruptor 适用于高吞吐量的消息传递系统，例如消息队列，以及实时消息等。

示例代码：

public class MessageEvent {
    private String message;
    public void setMessage(String message) { this.message = message; }
    public String getMessage() { return message; }
}

public class MessageEventHandler implements EventHandler {
    @Override
    public void onEvent(MessageEvent event, long sequence, boolean endOfBatch) {
        System.out.println("Received message: " + event.getMessage());
    }
}

public class DisruptorMessageQueue {
    public static void main(String[] args) {
        Disruptor disruptor = new Disruptor<>(
                MessageEvent::new,
                1024,
                Executors.defaultThreadFactory(),
                ProducerType.SINGLE,
                new YieldingWaitStrategy()
        );
        
        disruptor.handleEventsWith(new MessageEventHandler());
        disruptor.start();
        
        RingBuffer ringBuffer = disruptor.getRingBuffer();
        ringBuffer.publishEvent((event, sequence) -> event.setMessage("Hello Disruptor"));
    }
}

2.4. 实时数据分析

Disruptor 可用于高并发环境下的实时数据流处理。

示例代码：

public class DataEvent {
    private double value;
    public void setValue(double value) { this.value = value; }
}

public class DataAnalyzer implements EventHandler {
    @Override
    public void onEvent(DataEvent event, long sequence, boolean endOfBatch) {
        System.out.println("Analyzing data: " + event.value);
    }
}

2.5. 并发任务调度

在高并发环境下，使用 Disruptor 可以构建高效的异步任务调度系统。

示例代码：

public class TaskEvent {
    private Runnable task;
    public void setTask(Runnable task) { this.task = task; }
}

public class TaskHandler implements EventHandler {
    @Override
    public void onEvent(TaskEvent event, long sequence, boolean endOfBatch) {
        event.task.run();
    }
}

3. 总结

Disruptor 在低延迟、高吞吐场景下表现优异，适用于事件处理、日志记录、消息传递、实时数据分析和并发任务调度等应用。合理选择 WaitStrategy 和 ProducerType，可以进一步优化性能。

如果你的应用对并发性能有极高要求，Disruptor 绝对值得一试！

4.最后

下期将介绍Disruptor 的核心原理， 欢迎关注加瓦点灯，不错过每一次的干货！