Scala example source code file (Replayer.scala)

This example Scala source code file (Replayer.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

boolean, boolean, eof, io, logger, logreplay, logreplay, none, option, option, pickler, some, string, string, unpicklesuccess

The Scala Replayer.scala source code

package scala.tools.nsc.io

import java.io.{Reader, Writer}

import Pickler._
import Lexer.{Token, EOF}

abstract class LogReplay {
  def logreplay(event: String, x: => Boolean): Boolean
  def logreplay[T: Pickler](event: String, x: => Option[T]): Option[T]
  def close()
  def flush()
}

class Logger(wr0: Writer) extends LogReplay {
  val wr = new PrettyWriter(wr0)
  private var first = true
  private def insertComma() = if (first) first = false else wr.write(",")

  def logreplay(event: String, x: => Boolean) = {
    val xx = x
    if (xx) { insertComma(); pkl[Unit].labelled(event).pickle(wr, ()) }
    xx
  }
  def logreplay[T: Pickler](event: String, x: => Option[T]) = {
    val xx = x
    xx match {
      case Some(y) => insertComma(); pkl[T].labelled(event).pickle(wr, y)
      case None =>
    }
    xx
  }
  def close() { wr.close() }
  def flush() { wr.flush() }
}

object NullLogger extends LogReplay {
  def logreplay(event: String, x: => Boolean) = x
  def logreplay[T: Pickler](event: String, x: => Option[T]) = x
  def close() {}
  def flush() {}
}

class Replayer(raw: Reader) extends LogReplay {
  private val rd = new Lexer(raw)
  private var nextComma = false

  private def eatComma() =
    if (nextComma) { rd.accept(','); nextComma = false }

  def logreplay(event: String, x: => Boolean) =
    if (rd.token == EOF) NullLogger.logreplay(event, x)
    else {
      eatComma()
      pkl[Unit].labelled(event).unpickle(rd) match {
        case UnpickleSuccess(_) => nextComma = true; true
        case _ => false
      }
    }

  def logreplay[T: Pickler](event: String, x: => Option[T]) =
    if (rd.token == EOF) NullLogger.logreplay(event, x)
    else {
      eatComma()
      pkl[T].labelled(event).unpickle(rd) match {
        case UnpickleSuccess(y) => nextComma = true; Some(y)
        case _ => None
      }
    } 

  def close() { raw.close() }
  def flush() {}
}