Scala example source code file (ReflectiveRunner.scala)

This example Scala source code file (ReflectiveRunner.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, classnotfoundexception, consolefilemanager, consolefilemanager, list, loading, loading, net, network, nil, nil, reflectiverunner, some, string, urlclassloader

The Scala ReflectiveRunner.scala source code

/* NEST (New Scala Test)
 * Copyright 2007-2011 LAMP/EPFL
 * @author Philipp Haller
 */

// $Id$

package scala.tools.partest
package nest

import scala.tools.nsc.Properties.{ setProp, propOrEmpty }
import scala.tools.nsc.util.ClassPath
import scala.tools.nsc.io
import io.Path
import RunnerUtils._
import java.net.URLClassLoader

/* This class is used to load an instance of DirectRunner using
 * a custom class loader.
 * The purpose is to "auto-detect" a good classpath for the
 * rest of the classes (Worker, CompileManager etc.), so that
 * the main NestRunner can be started merely by putting its
 * class on the classpath (ideally).
 */
class ReflectiveRunner {
  // TODO: we might also use fileManager.CLASSPATH
  // to use the same classes as used by `scala` that
  // was used to start the runner.  
  val sepRunnerClassName = "scala.tools.partest.nest.ConsoleRunner"

  def main(args: String) {
    val argList = (args.split("\\s")).toList
    
    if (isPartestDebug)
      showAllJVMInfo

    // find out which build to test
    val buildPath = searchPath("--buildpath", argList)
    val classPath = searchPath("--classpath", argList)
    val fileManager =
      if (!buildPath.isEmpty)
        new ConsoleFileManager(buildPath.get)
      else if (!classPath.isEmpty)
        new ConsoleFileManager(classPath.get, true)
      else if (argList contains "--pack")
        new ConsoleFileManager("build/pack")
      else // auto detection
        new ConsoleFileManager

    import fileManager.
      { latestCompFile, latestLibFile, latestPartestFile, latestFjbgFile, latestScalapFile }
    val files =
      Array(latestCompFile, latestLibFile, latestPartestFile, latestFjbgFile, latestScalapFile) map (x => io.File(x))

    val sepUrls   = files map (_.toURL)
    val sepLoader = new URLClassLoader(sepUrls, null)

    if (isPartestDebug)
      println("Loading classes from:\n" + sepUrls.mkString("\n"))
    
    val paths = classPath match {
      case Some(cp) => Nil
      case _        => files.toList map (_.path)
    }
    val newClasspath = ClassPath.join(paths: _*)
    
    setProp("java.class.path", newClasspath)
    setProp("scala.home", "")
    
    if (isPartestDebug)
      for (prop <- List("java.class.path", "sun.boot.class.path", "java.ext.dirs"))
        println(prop + ": " + propOrEmpty(prop))

    try {
      val sepRunnerClass  = sepLoader loadClass sepRunnerClassName
      val sepRunner       = sepRunnerClass.newInstance()
      val sepMainMethod   = sepRunnerClass.getMethod("main", Array(classOf[String]): _*)
      val cargs: Array[AnyRef] = Array(args)
      sepMainMethod.invoke(sepRunner, cargs: _*)
    }
    catch {
      case cnfe: ClassNotFoundException =>
        cnfe.printStackTrace()
        NestUI.failure(sepRunnerClassName +" could not be loaded from:\n")
        sepUrls foreach (x => NestUI.failure(x + "\n"))
    }
  }
}