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Scala example source code file (MainGenericRunner.scala)

This example Scala source code file (MainGenericRunner.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

array, array, boolean, boolean, either, global, io, left, maingenericrunner, maingenericrunner, net, network, nil, right, scala, string, string

The Scala MainGenericRunner.scala source code

/* NSC -- new Scala compiler
 * Copyright 2006-2011 LAMP/EPFL
 * @author  Lex Spoon
 */

package scala.tools.nsc

import java.io.IOException
import java.net.URL
import scala.tools.util.PathResolver

import io.{ File }
import util.{ ClassPath, ScalaClassLoader }
import Properties.{ versionString, copyrightString }
import interpreter.{ ILoop }
import GenericRunnerCommand._

/** An object that runs Scala code.  It has three possible
  * sources for the code to run: pre-compiled code, a script file,
  * or interactive entry.
  */
class MainGenericRunner {
  def errorFn(ex: Throwable): Boolean = {
    ex.printStackTrace()
    false
  }
  def errorFn(str: String): Boolean = {
    Console println str
    false
  }

  def process(args: Array[String]): Boolean = {
    val command = new GenericRunnerCommand(args.toList, (x: String) => errorFn(x))
    import command.{ settings, howToRun, thingToRun }
    def sampleCompiler = new Global(settings)   // def so its not created unless needed
    
    if (!command.ok)                      return errorFn("\n" + command.shortUsageMsg)
    else if (settings.version.value)      return errorFn("Scala code runner %s -- %s".format(versionString, copyrightString))
    else if (command.shouldStopWithInfo)  return errorFn(command getInfoMessage sampleCompiler)

    def isE   = !settings.execute.isDefault
    def dashe = settings.execute.value

    def isI   = !settings.loadfiles.isDefault
    def dashi = settings.loadfiles.value
    
    def combinedCode  = {
      val files   = if (isI) dashi map (file => File(file).slurp()) else Nil
      val str     = if (isE) List(dashe) else Nil
      
      files ++ str mkString "\n\n"
    }
    
    def runTarget(): Either[Throwable, Boolean] = howToRun match {
      case AsObject =>
        ObjectRunner.runAndCatch(settings.classpathURLs, thingToRun, command.arguments)
      case AsScript =>
        ScriptRunner.runScriptAndCatch(settings, thingToRun, command.arguments)
      case AsJar    =>
        ObjectRunner.runAndCatch(
          File(thingToRun).toURL +: settings.classpathURLs,
          new io.Jar(thingToRun).mainClass getOrElse sys.error("Cannot find main class for jar: " + thingToRun),
          command.arguments
        )
      case _  =>
        // We start the repl when no arguments are given.
        Right(new ILoop process settings)
    }
    
    /** If -e and -i were both given, we want to execute the -e code after the
     *  -i files have been included, so they are read into strings and prepended to
     *  the code given in -e.  The -i option is documented to only make sense
     *  interactively so this is a pretty reasonable assumption.
     *
     *  This all needs a rewrite though.
     */
    if (isE) {
      ScriptRunner.runCommand(settings, combinedCode, thingToRun +: command.arguments)
    }
    else runTarget() match {
      case Left(ex) => errorFn(ex)
      case Right(b) => b
    }      
  }
}

object MainGenericRunner extends MainGenericRunner {
  def main(args: Array[String]) {
    if (!process(args))
      sys.exit(1)
  }
}

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