hussachai

import scala.annotation.tailrec
import java.io.File

object FirstHomework extends App {
  
  //homework sum 1 to n using recursion
  def sumN(n: Int) = {
    @tailrec
    def sum(c: Int, acc: Int): Int = {
      if(c == 0) acc

hussachai

import scala.util.Try

object FirstWeek extends App {
  
  lazy val lazy1 = 1 //evaluate once when needed
  def lazy2 = 2      //evaluate when called
  val eager = 3      //evaluate immediately
  
  object Dog {
    def name = {

hussachai

var socket = null
function subscribe(channel) {
    var subscribeUrl = jsRoutes.controllers.Application.subscribe().webSocketURL() + "?channel=" + channel
    console.log("Subscribed to: " + subscribeUrl)
    socket = new WebSocket(subscribeUrl)
    socket.onmessage = function(event) {
        $("#messages" ).prepend("<div>" + event.data + "</div>")
    }
    socket.onclose = function(event) {
        console.log(event)

hussachai

class SubscribeActor(redis: RedisClient, out: ActorRef, 
    channels: Seq[String] = Nil, patterns: Seq[String] = Nil) extends RedisSubscriberActor(
    new InetSocketAddress(redis.host, redis.port), channels, patterns,
    onConnectStatus = connected => { println(s"connected: $connected") }) {

  def onMessage(message: Message) {
    out ! message.data.decodeString("UTF-8")
  }

  def onPMessage(pmessage: PMessage) {}

hussachai

class Application extends Controller {
  
  ... 
  
  implicit val akkaSystem = akka.actor.ActorSystem()
  
  val redis = RedisClient()
  
  def index = Action { implicit request =>
    Ok(views.html.pubsub())

hussachai

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Level;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;

@BenchmarkMode({Mode.Throughput})

hussachai

╔══════╦══════╦════════╗
║ Col1 ║ Col2 ║ NumCol ║
╠══════╬══════╬════════╣
║ MMM  ║ MMM  ║ MMM    ║
║ 111  ║ 111  ║ 111    ║
║ AAA  ║ AAA  ║ AAA    ║
╚══════╩══════╩════════╝

hussachai

Filter then sort then map then collect
+----------+-------------+---------+-------+
| Language |  Benchmark  |  Score  | Error |
+----------+-------------+---------+-------+
| Java     | Collections |  13,615 |   255 |
| Java     | Streams     |  11,861 |   213 |
| Scala    | Collections |  45,009 |   805 | <-- (3)
| Scala    | Streams     |  56,409 |   882 | <-- (2)
| Scala    | Views       | 139,639 | 2,875 | <-- (1)
+----------+-------------+---------+-------+

hussachai

Find first
+----------+-------------+------------+-----------+
| Language |  Benchmark  |   Score    |   Error   |
+----------+-------------+------------+-----------+
| Java     | Collections | 80,444,836 | 1,358,358 | <-- (1)
| Java     | Streams     | 26,209,187 |   469,668 |
| Scala    | Collections | 65,145,791 | 2,699,582 | <-- (3)
| Scala    | Streams     |  6,923,533 |   179,960 | 
| Scala    | Views       | 58,082,123 | 1,004,918 | <-- (2)
+----------+-------------+------------+-----------+

hussachai

Map then reduce
+----------+-------------+------------+-------------+
| Language |  Benchmark  |   Score    |    Error    |
+----------+-------------+------------+-------------+
| Java     | Collections | 10,989,113 |     319,941 | <-- (1)
| Java     | Streams     |    944,391 |      16,689 | <-- (2)
| Scala    | Collections |    314,736 |       6,594 | 
| Scala    | Streams     |    115,335 |       1,467 |
| Scala    | Views       |    476,832 |       9,358 | <-- (3)
+----------+-------------+------------+-------------+