nicholasren

def solveRPN(expression: String):String = {
  expression.split(" ").foldLeft(List[String]()) {
    (stack:List[String], e:String) =>
      e match {
        case "*" =>
          stack match {
            case List(z) => List(z)
              case x :: y :: ys =>  (y.toInt * x.toInt).toString :: ys
          }
        case "+" =>

nicholasren

 val fa = callToRemoteServiceA();
 val fb = callToRemoteServiceB();

 val fc = callToRemoteServiceC(fa.get());
 val fd = callToRemoteServiceD(fb.get());
 val fe = callToRemoteServiceE(fb.get());
 
 val executor = new ThreadPoolExecutor(4, 4, 1, TimeUnit.MINUTES, new LinkedBlockingQueue[Runnable]())

nicholasren

//-------------------------------------------//
// function as parameter java implementation //
//-------------------------------------------//

class UerFetcher  implement Callable<User>  { 
  private   String userId;
  
  @Autowired
  private  UserService  userService;
  

nicholasren

//-------------------------------------//
//  readFile is a high order function  //
//  which can take another function    //
//  as parameter                       //
//-------------------------------------//

def using[T](f: File)(handler: FileInputStream => T): T = {
  val resource = new java.io.FileInputStream(f)
  try {
    handler(resource)

nicholasren

val userFetcher: String => User = {
  //...
}
val commentFetcher: User => List[Comment] = {
  //... 
}
val userCommentFetcher : String => List[Comment] = userFetcher andThen commentFetcher

nicholasren

case class Option[T]
case class Some(t: T) extends Option[T]
case class None extends Option[T]

val possibleNumber = Some(1)

val numbers = possibleNumber match {
      case Some(x) => x
      case None => 0
}

nicholasren

//in post controller

User user = null;

try {
  user = userService.findById(userId)
} catch (UserNotFoundException e) {
  throw //handling exception
}

nicholasren

trait Quack {
    this: { def quack(): Unit } =>
}

class Duck extends Quack {
    def quack() = {
      println("Quack, Quack...")
    }
}

nicholasren

package actors

import akka.actor._
import scala.concurrent.{Future, ExecutionContext}
import scala.concurrent.duration._

import ExecutionContext.Implicits.global
import java.io.{PrintWriter, FileOutputStream}
import rx.lang.scala.Observable
import rx.lang.scala.Observable._

nicholasren

package com.thoughtworks;

import org.apache.http.HttpEntity;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClients;

import java.io.IOException;
import java.lang.String;