Amazed by Scala #1: objects and compilation

7 minutes and here is an object, that can be compiled into java classes:

import scala.actors._
import Actor._

object TopStock {
 val symbols = List( "AAPL", "GOOG", "IBM", "MSFT")
 val receiver = self
 val year = 2008
 
  def main(args: Array[String]) = {
 symbols.foreach { symbol =>
   actor { receiver ! getYearEndClosing(symbol, year) }
 }
  
 val (topStock, highestPrice) = getTopStock(symbols.length)
 printf("Top stock of %d is %s closing at price %f\n", year, topStock, highestPrice)
  }

 def getYearEndClosing(symbol : String, year : Int) = {
   val url = "http://ichart.finance.yahoo.com/table.csv?s="+ 
   symbol + "&a=11&b=01&c=" + year + "&d=11&e=31&f=" + year+
             "&g=m"
   
   val data = io.Source.fromURL(url).mkString
   val price = data.split("\n")(1).split(",")(4).toDouble
   (symbol, price)
 }

 def getTopStock(count : Int) : (String, Double) = {
   (1 to count).foldLeft("", 0.0) { (previousHigh, index) =>
  receiveWithin(10000) {
    case (symbol : String, price : Double) =>
   if (price > previousHigh._2) (symbol, price) else previousHigh
  }
   }
 }  
}

Saved in TopStock.scala. Compiled with

> scalac TopStock.scala

ran with

> scala TopStock

Top stock of 2008 is GOOG closing at price 307,650000