使用Java5+GPar来控制事件的处理

[foxgem]

原文：http://java.dzone.com/articles/java-5-gpars-throttling-action?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+zones%2Fgroovy+%28Groovy+Zone%29&utm_content=Google+Reader

 

作者的这篇文章起源于这样一个问题：“在一个持续产生事件的系统中，如何保证在固定时间（如15秒）内只处理1个事件”。作者以经典的“睡觉的理发师”为例给出了他的做法，解法分两部分：

1。事件处理

    class Customer {
     String name
    }
    
    // waiting room can't hold more than 12!
    def waitingRoom = new ArrayBlockingQueue(12)  <==jdk5中对象，取元素时，有则立刻返回；否则，等待
    
    def barber = Executors.newScheduledThreadPool(1)  <==jdk5中对象
    barber.scheduleAtFixedRate({
         println 'Barber: Next customer please!'
         Customer customer = waitingRoom.take()
         println "${customer.name} gets a haircut at ${new Date().format('H:m:s')}"
     } as Runnable, 0, 15, TimeUnit.MINUTES)

 

2。产生事件

    def barberShop = new PooledActorGroup().reactor {message ->  <==使用GPar完成
     switch (message) {
         case Enter:
             println "${message.customer.name} waits for a haircut..."
             waitingRoom.add(message.customer)
             break
     }
    }
   
    class Enter {
     Customer customer
    }
   
    barberShop << new Enter(customer: new Customer(name: 'Jerry'))
    barberShop << new Enter(customer: new Customer(name: 'Phil'))
    barberShop << new Enter(customer: new Customer(name: 'Bob'))
    barberShop << new Enter(customer: new Customer(name: 'Ron'))