Scala example source code file (WrappedProperties.scala)

This example Scala source code file (WrappedProperties.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

accesscontrol, accesscontrolexception, iterator, none, none, option, propertiestrait, security, some, some, string, string, t, wrappedproperties, wrappedproperties

The Scala WrappedProperties.scala source code

/* NSC -- new Scala compiler
 * Copyright 2006-2011 LAMP/EPFL
 * @author  Paul Phillips
 */

package scala.tools
package reflect

import scala.util.PropertiesTrait
import java.security.AccessControlException

/** For placing a wrapper function around property functions.
 *  Motivated by places like google app engine throwing exceptions
 *  on property lookups.
 */
trait WrappedProperties extends PropertiesTrait {
  def wrap[T](body: => T): Option[T]

  protected def propCategory   = "wrapped"
  protected def pickJarBasedOn = this.getClass

  override def propIsSet(name: String)               = wrap(super.propIsSet(name)) exists (x => x)
  override def propOrElse(name: String, alt: String) = wrap(super.propOrElse(name, alt)) getOrElse alt
  override def setProp(name: String, value: String)  = wrap(super.setProp(name, value)) orNull
  override def clearProp(name: String)               = wrap(super.clearProp(name)) orNull
  override def envOrElse(name: String, alt: String)  = wrap(super.envOrElse(name, alt)) getOrElse alt
  override def envOrNone(name: String)               = wrap(super.envOrNone(name)) match { case Some(x) => x ; case _ => None }

  def systemProperties: Iterator[(String, String)] = {
    import scala.collection.JavaConverters._
    wrap(System.getProperties.asScala.iterator) getOrElse Iterator.empty
  }
}

object WrappedProperties {
  object AccessControl extends WrappedProperties {
    def wrap[T](body: => T) = try Some(body) catch { case _: AccessControlException => None }
  }
}