scala演员:长期运行io操作

时间:2010-01-14 14:35:45

标签: performance scala concurrency actor

对于包含长时间运行操作的actor,我遇到了一些麻烦,在我看来是持久性套接字连接。这里有一些测试代码,如果我创建的实例少于4个,那么运行正常,但是如果我创建更多实例,我总是只有三个或有时四个并发套接字连接,因为其他的超时。 我想知道为什么会这样,我的代码是否有明显的错误。

package test

import actors.Actor
import actors.Actor._
import java.io.{PrintStream, DataOutputStream, DataInputStream}
import java.net.{Socket, InetAddress}
import java.text.{SimpleDateFormat}
import java.util.{Calendar}

case class SInput(input: String)
case class SOutput(output: String)
case class SClose
case class SRepeat

import scala.xml._

class Config(xml: Node) {
  var nick: String = (xml \ "nick").text
  var realName: String = (xml \ "realName").text
  var server: String = (xml \ "ip").text
  var port: Int = (xml \ "port").text.toInt
  var identPass: String = (xml \ "identPass").text
  var joinChannels: List[String] = List.fromString((xml \ "join").text.trim, ' ')
}

object ServerStarter {
  def main(args: Array[String]): Unit = {
    var servers = List[Server]()

    val a = actor {
      loop {
        receive {
          case config: Config =>
            actor {
              val server = new Server(config)
              servers = server :: servers
              server.start
            }
        }
      }
    }

    val xml = XML.loadFile("config.xml")
    (xml \ "server").elements.foreach(config => a ! new Config(config))
  }
}


class Server(config: Config) extends Actor {
  private var auth = false
  private val socket = new Socket(InetAddress.getByName(config.server), config.port)
  private val out = new PrintStream(new DataOutputStream(socket.getOutputStream()))
  private val in = new DataInputStream(socket.getInputStream())

  def act = {
    val _self = this
    _self ! SRepeat

    while (true) {
      receive {
        case SRepeat =>
          try {
            val input = in.readLine
            if (input != null) {
              actor {_self ! SInput(input)}
            } else {
              actor {_self ! SClose}
            }
          } catch {
            case e: Exception =>
              println(e)
              actor {_self ! SClose}
          }

        case SClose =>
          println(getDate + " closing: " + config.server + " mail: " + mailboxSize)
          try {
            socket.close
            in.close
            out.close
          } catch {
            case e: Exception =>
              println(e)
          }

        case SInput(input: String) =>
          println(getDate + " " + config.server + " IN => " + input + " mail: " + mailboxSize)
          actor {onServerInput(_self, input)}
          _self ! SRepeat

        case SOutput(output: String) =>
          println(getDate + " " + config.server + " OUT => " + output + " mail: " + mailboxSize)
          actor {
            out.println(output)
            out.flush()
          }

        case x =>
          println("unmatched: " + x + " mail: " + mailboxSize)
      }
    }
  }

  private def getDate = {
    new SimpleDateFormat("hh:mm:ss").format(Calendar.getInstance().getTime());
  }

  def onServerInput(a: Actor, input: String) = {
    if (!auth) {
      authenticate(a)
    }
    else if (input.contains("MOTD")) {
      identify(a)
      join(a)
    }
    else if (input.contains("PING")) {
      pong(a, input)
    } else {
    }
  }

  def authenticate(a: Actor) = {
    a ! SOutput("NICK " + config.nick)
    a ! SOutput("USER " + config.nick + " 0 0 : " + config.realName)
    auth = true
  }

  def pong(a: Actor, input: String) = {
    a ! SOutput("PONG " + input.split(":").last)
  }

  def identify(a: Actor) = {
    if (config.identPass != "") {
      a ! SOutput("nickserv :identify " + config.nick + " " + config.identPass)
    }
  }

  def join(a: Actor) = {
    config.joinChannels.foreach(channel => a ! SOutput("JOIN " + channel))
  }
}

顺便说一句。我正在使用scala 2.7.6 final。

1 个答案:

答案 0 :(得分:6)

这里有奇怪的事情。例如:

actor { 
  val server = new Server(config) 
  servers = server :: servers 
  server.start 
}

或者:

actor {_self ! SClose}  

方法actor是一个Actor工厂。例如,在第一种情况下,您正在创建一个将创建另一个actor的actor(因为Server是一个Actor),然后启动它。

让我再说一遍:actor {}之间的一切都是演员。在那个演员里面,你正在做new Server,它创建了另一个演员。那是在receive里面,当然,它是演员的一部分。因此,在演员中,你正在创建一个将创建一个演员的演员。

在第二个例子中,您正在创建一个演员,只是为了向自己发送消息。这对我来说毫无意义,但我并不是所有经验丰富的演员。