Scala example source code file (InteractiveReader.scala)

This example Scala source code file (InteractiveReader.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, boolean, history, interactivereader, interactivereader, interrupted, io, ioexception, list, r, simplereader, string, string, unit, unit

The Scala InteractiveReader.scala source code

/* NSC -- new Scala compiler
 * Copyright 2005-2011 LAMP/EPFL
 * @author Stepan Koltsov
 */

package scala.tools.nsc
package interpreter

import java.io.IOException
import java.nio.channels.ClosedByInterruptException
import scala.util.control.Exception._
import session.History
import InteractiveReader._
import Properties.isMac

/** Reads lines from an input stream */
trait InteractiveReader {
  val interactive: Boolean
  
  def init(): Unit
  def reset(): Unit

  def history: History
  def completion: Completion
  def keyBindings: List[KeyBinding]
  def eraseLine(): Unit
  def redrawLine(): Unit
  def currentLine: String

  def readYesOrNo(prompt: String, alt: => Boolean): Boolean = readOneKey(prompt) match {
    case 'y'  => true
    case 'n'  => false
    case _    => alt
  }
  def readAssumingNo(prompt: String)  = readYesOrNo(prompt, false)
  def readAssumingYes(prompt: String) = readYesOrNo(prompt, true)
  
  protected def readOneLine(prompt: String): String
  protected def readOneKey(prompt: String): Int

  def readLine(prompt: String): String =
    // hack necessary for OSX jvm suspension because read calls are not restarted after SIGTSTP
    if (isMac) restartSysCalls(readOneLine(prompt), reset())
    else readOneLine(prompt)
}

object InteractiveReader {
  val msgEINTR = "Interrupted system call"
  def restartSysCalls[R](body: => R, reset: => Unit): R =
    try body catch {
      case e: IOException if e.getMessage == msgEINTR => reset ; body
    }
  
  def apply(): InteractiveReader = SimpleReader()
  @deprecated("Use `apply` instead.", "2.9.0")
  def createDefault(): InteractiveReader = apply()
}