package scala.sys
import scala.collection.{ mutable, Iterator }
import scala.collection.JavaConverters._
import java.security.AccessControlException
class SystemProperties extends mutable.Map[String, String] {
override def empty = new SystemProperties
override def default(key: String): String = null
def iterator: Iterator[(String, String)] =
wrapAccess(System.getProperties().asScala.iterator) getOrElse Iterator.empty
def get(key: String) =
wrapAccess(Option(System.getProperty(key))) flatMap (x => x)
override def contains(key: String) =
wrapAccess(super.contains(key)) exists (x => x)
def -= (key: String): this.type = { wrapAccess(System.clearProperty(key)) ; this }
def += (kv: (String, String)): this.type = { wrapAccess(System.setProperty(kv._1, kv._2)) ; this }
def wrapAccess[T](body: => T): Option[T] =
try Some(body) catch { case _: AccessControlException => None }
}
object SystemProperties {
def exclusively[T](body: => T) = this synchronized body
implicit def systemPropertiesToCompanion(p: SystemProperties): SystemProperties.type = this
private lazy val propertyHelp = mutable.Map[String, String]()
private def addHelp[P <: Prop[_]](p: P, helpText: String): P = {
propertyHelp(p.key) = helpText
p
}
private def str(key: String, helpText: String) = addHelp(Prop[String](key), helpText)
private def bool(key: String, helpText: String): BooleanProp = addHelp[BooleanProp](
if (key startsWith "java.") BooleanProp.valueIsTrue(key) else BooleanProp.keyExists(key),
helpText
)
def help(key: String) = propertyHelp.getOrElse(key, "")
lazy val headless = bool("java.awt.headless", "system should not utilize a display device")
lazy val preferIPv4Stack = bool("java.net.preferIPv4Stack", "system should prefer IPv4 sockets")
lazy val preferIPv6Addresses = bool("java.net.preferIPv6Addresses", "system should prefer IPv6 addresses")
lazy val noTraceSupression = bool("scala.control.noTraceSuppression", "scala should not suppress any stack trace creation")
lazy val traceSourcePath = str("scala.control.sourcepath", "sourcepath for looking up stack trace elements")
}