joel113

// Type parameter placeholder: S[_]
def str[T, S[_]](ss: S[T]): String = ss.toString
val s1 = str(Seq(1, 2, 3))    // "List(1, 2, 3)"

// Function parameter placeholder: _.toUpperCase
val loud = Seq("hello world!").map(_.toUpperCase) // List(HELLO WORLD!)

// Match placeholder: _ in the first two case clauses
Seq(Seq('a', 'b', 'c'), Seq(1, 2, 3), Seq(1.1, 2.2)).map { 
  seq => seq match {

joel113

import io.circe._
import io.circe.parser._
import io.circe.syntax._

import akka.http.scaladsl.marshalling.{Marshaller, ToEntityMarshaller}
import akka.http.scaladsl.model.{ContentTypeRange, HttpEntity}
import akka.http.scaladsl.model.MediaTypes.`application/json`
import akka.http.scaladsl.unmarshalling.{FromEntityUnmarshaller, Unmarshaller}

import scala.concurrent.Future

joel113

import io.circe._
import io.circe.parser._
import io.circe.syntax._

import akka.http.scaladsl.marshalling.{Marshaller, ToEntityMarshaller}
import akka.http.scaladsl.model.{ContentTypeRange, HttpEntity}
import akka.http.scaladsl.model.MediaTypes.`application/json`
import akka.http.scaladsl.unmarshalling.{FromEntityUnmarshaller, Unmarshaller}

import scala.concurrent.Future

joel113

abstract class Animal

case class Cat(name: String) extends Animal

case class Dog(name: String, owner: String) extends Animal

def checkAnimal(animal: Animal): String = {
  animal match {
    case Cat(name) => "The name of the cat is $name."
    case _ => "Its just a dog."

joel113

def sequencesPatternMatching(sequence: Any): String = {
  sequence match {
    case List(singleElement) => s"I'm a list with one element: $singleElement"
    case List(_, _*) => s"I'm a list with one or multiple elements: sequence"
    case Vector(1, 2, _*) => s"I'm a vector: $sequence"
    case _ => s"I'm an unrecognized sequence. My value: $sequence"
  }
}

sequencesPatternMatching(Seq(1,2,3))

joel113

package com.joel.akka.streams

import akka.actor.ActorSystem
import akka.stream.scaladsl._
import akka.Done

import scala.concurrent._

object Main {

joel113

package com.joel.akka.streams

import akka.actor.ActorSystem
import akka.stream.scaladsl._
import akka.Done

import scala.concurrent._

object Main {

joel113

import scala.collection.immutable.HashMap

object InstanceOf {

  /**
   * Investigation of the compile and runtime behaviour of the cast operation asInstanceOf of Scala.
   *
   * @param args
   */
  def main(args: Array[String]): Unit = {

joel113

import io.circe.Json.Null
import io.circe.{Encoder, Json, ObjectEncoder}
import io.circe.generic.auto._
import io.circe.generic.semiauto.deriveEncoder
import io.circe.syntax._

object example {

  def main(args: Array[String]) {

joel113

import java.util.Optional

import scala.jdk.javaapi.OptionConverters

object example {

  case class ExampleClassD(e: Int)

  case class ExampleClassC(d: Optional[Int])