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

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

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

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

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 "+" =>