テキストファイルを読み込んで 指定した文字列を含む行を出力するサンプル

CheckLog.scala

import scala.io.Source

object CheckLog {

  case class Args(
    filename: String,
    exp: String
  )

  def main(args: Array[String]) {

    val argsOption = parseArgs(args.toList)

    val s = Source.fromFile(argsOption.get.filename,"UTF8")
    val p = argsOption.get.exp.r

    try {
      for (line <- s.getLines) {
        var i = i + 1
        val l = p.findFirstMatchIn(line)
        l.foreach{ lf => println("*** " + lf.matched + " *** " + "Line:" + i + " " + lf.source)}
      }
    } finally {
      s.close
    }
  }

  def parseArgs(args: List[String]): Option[Args] = {

    var fileName = "./takuya71.log"
    var exp = ".*error|hoge"

    @scala.annotation.tailrec
    def parseArgsHelper(args: List[String]): Args = {
      args match {
        case "-f" :: x :: rest => {
          fileName = x
          parseArgsHelper(rest)
        }
        case "-e" :: x :: rest => {
          exp = x
          parseArgsHelper(rest)
        }
        case _ => Args(fileName,exp)
    }
  }

  try { 
    Some(parseArgsHelper(args))
  } 
   catch {
     case _ =>  None }
  }

}