docs/examples/actors/BoundedBufferTest.scala


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package examples.actors

import scala.actors.Actor._

class BoundedBuffer[T](N: int) {
  private case class Get
  private case class Put(x: T)

  private val buffer = actor {
    val buf = new Array[T](N)
    var in = 0; var out = 0; var n = 0
    while(true) {
      receive {
        case Put(x) if n < N =>
          buf(in) = x; in = (in + 1) % N; n = n + 1; reply()
        case Get() if n > 0 =>
          val r = buf(out); out = (out + 1) % N; n = n - 1; reply(r)
      }
    }
  }

  def put(x: T): Unit = buffer !? Put(x)

  def get: T = (buffer !? Get()).asInstanceOf[T]
}

object BoundedBufferTest {
  def main(args: Array[String]) = {
    val buf = new BoundedBuffer[Int](1)
    buf.put(42)
    scala.Console.println("" + buf.get)
  }
}