Disruptor framework in the Java library concurrent programming solution
The DISRUPTOR framework is a high -performance, low -delayed concurrent programming solution that provides a novel way to deal with the problem in the Java class library.The framework was developed by LMAX Exchange. It was originally designed for the high -frequency trading system in the financial field, but it has been widely used in various fields.
In the traditional concurrent programming model, the common method is to use locks to protect shared resources, so as to ensure that there is only one thread to access the resource at the same time.However, the use of locks may cause a series of problems, such as dead locks, competition conditions and threads, thereby reducing the performance and scalability of the system.
The DISRUPTOR framework provides another alternative solution. It uses a data structure called "ring buffer" to solve concurrent programming problems.The ring buffer is a fixed -sized cycle array, and each element is called "event".The DISRUPTOR framework connects the producer and consumers to the ring buffer. The producer writes the event into the buffer, and consumers read the incident from the buffer.
The key to using the DISRUPTOR framework to programming is to define an appropriate event processor.Event processor is responsible for dealing with events read from the ring buffer and perform specific business logic.In the DISRUPTOR framework, multiple event processors can be created and they are connected into an event processing chain.These processors can handle incidents parallel to improve the throughput and response performance of the system.
The following is a simple example to demonstrate the use of the DISRUPTOR framework:
import com.lmax.disruptor.RingBuffer;
import com.lmax.disruptor.dsl.Disruptor;
import java.nio.ByteBuffer;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
public class DisruptorExample {
public static void main(String[] args) {
// Create an event factory
EventFactory<LongEvent> eventFactory = new LongEventFactory();
// Specify the size of the ring buffer
int bufferSize = 1024;
// Create a thread pool
Executor executor = Executors.newFixedThreadPool(4);
// Create DISRUPTOR instance
Disruptor<LongEvent> disruptor = new Disruptor<>(eventFactory, bufferSize, executor);
// Set event processor
disruptor.handleEventsWith(new LongEventHandler());
// Start Disruptor
disruptor.start();
// Get the ring buffer
RingBuffer<LongEvent> ringBuffer = disruptor.getRingBuffer();
// Create a producer
LongEventProducer producer = new LongEventProducer(ringBuffer);
// Posted the event to the ring buffer
ByteBuffer bb = ByteBuffer.allocate(8);
for (long l = 0; l < 100; l++) {
bb.putLong(0, l);
producer.onData(bb);
}
// Turn off DISRUPTOR
disruptor.shutdown();
}
}
// Define an event class
class LongEvent {
private long value;
public void set(long value) {
this.value = value;
}
}
// Define an event factory
class LongEventFactory implements EventFactory<LongEvent> {
public LongEvent newInstance() {
return new LongEvent();
}
}
// Define an event processor
class LongEventHandler implements EventHandler<LongEvent> {
public void onEvent(LongEvent event, long sequence, boolean endOfBatch) {
System.out.println("Event: " + event.get());
}
}
// Define a producer
class LongEventProducer {
private final RingBuffer<LongEvent> ringBuffer;
public LongEventProducer(RingBuffer<LongEvent> ringBuffer) {
this.ringBuffer = ringBuffer;
}
public void onData(ByteBuffer bb) {
long sequence = ringBuffer.next();
try {
LongEvent event = ringBuffer.get(sequence);
event.set(bb.getLong(0));
} finally {
ringBuffer.publish(sequence);
}
}
}
The above code demonstrates an example of using the Disruptor framework.Among them, a DISRUPTOR instance is defined by creating a ring buffer and corresponding event factories.Then, by creating a producer, the incident is published to the ring buffer.Finally, set up an event processor to handle events read from the ring buffer.
The DISRUPTOR framework performs well when processing a large number of concurrent tasks. It allows the system to handle multiple events at the same time, thereby improving the throughput of the system.In the scenario of financial transactions, network communication, and real -time analysis, the DISRUPTOR framework is a very valuable concurrent programming solution.
