just a scala actor demo

import scala.actors._
import scala.actors.Actor._
import scala.util.Random
import java.util.Date
 
object Actors{
  def main(args: Array[String]){
    val actors = new Array[Actor](250000)
    for(i <- 0 to 249999){
       actors(i) = actor{
        loop{
          react{
            case fibNum: Int => calculate(fibNum, i)  
          }
        }
      }
    }
    val random = new Random()
    for(a <- actors){
      a ! random.nextInt(25)
    }
  }
  
  def calculate(fibNum: Int, i: Int) = {
    val answer = fibonacci(fibNum)
    if((i + 1) % 1000 == 0){
      val idPlusOne = i + 1
      println("The " + fibNum + "th fibonacci number is " + answer + " (thread: " + idPlusOne + ")")
    }
    if((i + 1) % 250000 == 0){
      System.exit(0)
    }
  }
  
  def fibonacci( n: Int): Int = n match {
    case 0 => 0
    case 1 => 1
    case _ => fibonacci(n -1) + fibonacci(n - 2)
  }
}

同等功能的java实现

import java.util.Date;
import java.util.Random;
 
public class JavaThreads extends Thread{
  
  private static int THREAD_COUNT = 250000;
  private int fibNum;
  private int jid;
  
  public JavaThreads(int id, int fibNum){
    this.jid = id;
    this.fibNum = fibNum;
  }
  
  public void run(){
    int answer = fibonacci(fibNum);
    if(this.jid % 1000 == 0){
      System.out.println("The " + fibNum + "th fibonacci number is " + answer + " (thread: " + this.jid + ")");
    }
  }
  
  private int fibonacci(int i){
    if(i < 2){ return i;}
    return fibonacci(i - 1) + fibonacci(i - 2);
  }
  
  public int getJid(){
    return jid;
  }
  
  public void setJid(int jid){
    this.jid = jid;
  }
  
  public int getFibNum(){
    return fibNum;
  }
  
  public void setFibNum(int fibNum){
    this.fibNum = fibNum;
  }
  
  public static void main(String args[]){
    Date beginDate = new Date();
    long memoryBegin = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
    JavaThreads threads[] = new JavaThreads[THREAD_COUNT];
    Random random = new Random();
    for(int i = 0; i < THREAD_COUNT; i++){
      threads[i] = new JavaThreads(i, random.nextInt(25));
    }
    for(JavaThreads thread : threads){
      thread.start();
    }
    
    long memoryEnd = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
    Date endDate = new Date();
    System.out.println("Completed in " + ((endDate.getTime() - beginDate.getTime())/1000) + " seconds");
    System.out.println("Used memory: " + (memoryEnd - memoryBegin));
  }
  
}