Scala example source code file (Coder.scala)

This example Scala source code file (Coder.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

coder, coder, def, ghi, int, int, map, map, seq, set, string, string, translation, unsupportedoperationexception

The Scala Coder.scala source code

package scala.collection.parallel.benchmarks
package misc






import collection._ //immutable._
import collection.parallel._//immutable._


class SeqCoder(words: List[String]) {
  
  private val m = Map(
      '2' -> "ABC", '3' -> "DEF", '4' -> "GHI", '5' -> "JKL", 
      '6' -> "MNO", '7' -> "PQRS", '8' -> "TUV", '9' -> "WXYZ")
      
  /** Invert the mnemnonics map to give a map from chars 'A' ... 'Z' to '2' ... '9' */
  private val charCode: Map[Char, Char] = 
    for ((digit, letters) <- m; letter <- letters) yield letter -> digit
    
  /** Maps a word to the digit string it represents, 
   * e.g. `Java` -> `5282`  */
  private def wordCode(word: String): String = word.toUpperCase map charCode
    
  /** A map from digit strings to the words that represent 
   *  them e.g. `5282` -> List(`Java`, `Kata`, `Lava`, ...)
   */
  val wordsForNum: Map[String, Seq[String]] = 
    (words groupBy wordCode).map(t => (t._1, t._2.toSeq)) withDefaultValue Seq()
  
  /** All ways to encode a number as a list of words */
  def encode(number: String): Set[Seq[String]] = 
    if (number.isEmpty) Set(Seq())
    else {
      val splits = (1 to number.length).toSet
      // for {
      //   split <- splits
      //   word <- wordsForNum(number take split)
      //   rest <- encode(number drop split)
      // } yield word :: rest
      val r = splits.flatMap(split => {
        val wfn = wordsForNum(number take split).flatMap(word => {
          val subs = encode(number drop split)
          subs.map(rest => word +: rest)
        })
        wfn
      })
      r
    }
    
  /** Maps a number to a list of all word phrases that can 
   *  represent it */
  def translate(number: String) = encode(number)// map (_ mkString " ")
  
  def ??? : Nothing = throw new UnsupportedOperationException
}

class ParCoder(words: List[String]) {
  
  private val m = Map(
      '2' -> "ABC", '3' -> "DEF", '4' -> "GHI", '5' -> "JKL", 
      '6' -> "MNO", '7' -> "PQRS", '8' -> "TUV", '9' -> "WXYZ")
      
  /** Invert the mnemnonics map to give a map from chars 'A' ... 'Z' to '2' ... '9' */
  private val charCode: Map[Char, Char] = 
    for ((digit, letters) <- m; letter <- letters) yield letter -> digit
    
  /** Maps a word to the digit string it represents, 
   * e.g. `Java` -> `5282`  */
  private def wordCode(word: String): String = word.toUpperCase map charCode
    
  /** A map from digit strings to the words that represent 
   *  them e.g. `5282` -> List(`Java`, `Kata`, `Lava`, ...)
   */
  val wordsForNum: Map[String, Seq[String]] = 
    (words groupBy wordCode).map(t => (t._1, t._2)) withDefaultValue Seq()
  
  /** All ways to encode a number as a list of words */
  def encode(number: String): Set[Seq[String]] = if (number.length > 12) {
    if (number.isEmpty) ParSet(ParSeq())
    else {
      val splits = (1 to number.length).toParSet
      for {
        split <- splits
        word <- wordsForNum(number take split)
        rest <- encode(number drop split)
      } yield word +: rest
    }
  } else {
    if (number.isEmpty) Set(Seq())
    else {
      val splits = (1 to number.length).toSet
      for {
        split <- splits
        word <- wordsForNum(number take split)
        rest <- encode(number drop split)
      } yield word +: rest
    }
  }
  
  /** Maps a number to a list of all word phrases that can 
   *  represent it */
  def translate(number: String) = {
    encode(number)// map (_ mkString " ")
  }
  
  def ??? : Nothing = throw new UnsupportedOperationException
}





object Coder extends BenchCompanion {
  def benchName = "Coder"
  def collectionName = "General"
  def apply(sz: Int, p: Int, what: String) = new Coder(sz, p, what)
  override def defaultSize = 100
}

class Coder(val size: Int, val parallelism: Int, val runWhat: String) extends Bench {
  def companion = Coder
  
  var seqcoder: SeqCoder = null
  var parcoder: ParCoder = null
  
  override def repetitionsPerRun = 1
  
  val code = "23284374729473626268379762538"
  
  reset
  
  def runseq {
    val translations = seqcoder.translate(code)
    //println(translations)
  }
  
  def runpar {
    val translations = parcoder.translate(code)
    //println(translations)
  }
  
  def reset = runWhat match {
    case "seq" =>
      seqcoder = new SeqCoder(Dictionary.wordlist)
      val t = seqcoder.translate(code)
      println("Translation check: " + t.size)
      //println(t)
    case "par" =>
      collection.parallel.tasksupport.environment.asInstanceOf[concurrent.forkjoin.ForkJoinPool].setParallelism(parallelism)
      parcoder = new ParCoder(Dictionary.wordlist)
      val t = parcoder.translate(code)
      println("Translation check: " + t.size)
      //println(t)
  }
  
  def comparisonMap = Map()
  
}