Scala example source code file (ForkSBT.scala)

This example Scala source code file (ForkSBT.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, d, list, list, none, option, option, some, string, string, t, task, taskmanager, taskmanager

The Scala ForkSBT.scala source code

/** Scala SBT build
 *  Copyright 2005-2010 LAMP/EPFL
 *  @author  Paul Phillips
 */

import sbt._

/** Worked out a way to fork sbt tasks, preserving all sbt command line
 *  options and without hardcoding anything.
 */
trait ForkSBT {
  self: BasicLayer =>

  def jvmArguments: List[String] = {
    import scala.collection.jcl.Conversions._
    import java.lang.management.ManagementFactory
    ManagementFactory.getRuntimeMXBean().getInputArguments().toList
  }
  
  private var extraJVMArgs: List[String] = Nil
  def withJVMArgs[T](args: String*)(body: => T): T = {
    val saved = extraJVMArgs
    extraJVMArgs = args.toList
    try { body }
    finally extraJVMArgs = saved
  }

  // Set a property in forked sbts to inhibit possible forking cycles.
  def markForked = "-D" + forkProperty + "=true"
  
  /** Forks a new process to run "sbt task task ...":
   */
  def forkTasks(tasks: String*): Boolean = {
    require (!isForked, "Tried to fork but sbt is already forked: " + tasks.mkString(" "))
    
    val sbtJar  = System.getProperty("java.class.path")
    val sbtMain = "xsbt.boot.Boot"  // ok, much of anything.
    val args   = jvmArguments ++ Seq(markForked, "-classpath", sbtJar, sbtMain) ++ tasks
    
    log.info("Forking: " + args.mkString("java ", " ", ""))
    Fork.java(None, args, StdoutOutput) == 0
  }
  def maybeFork(task: TaskManager#Task): Option[String] = maybeFork(task, "Error during external compilation.")
  def maybeFork(task: TaskManager#Task, errorMsg: String): Option[String] = {
    if (isForked) task.run
    else if (forkTasks("project " + this.name, task.name)) None
    else Some(errorMsg)
  }
}