Fatih pisfly

Applied Functional Programming with Scala - Notes

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

#The Problem We just described standard design issues you have when you start creating layers of services, DAOs and other components to implement an application. That blog/gist is here.

The goal is to think through some designs in order to develop something useful for an application.

#Working through Layers If you compose services and DAOs the normal way, you typically get imperative style objects. For example, imagine the following:

  object DomainObjects {

Title

<Additional information about your API call. Try to use verbs that match both request type (fetching vs modifying) and plurality (one vs multiple).>

URL

<The URL Structure (path only, no root url)>
Method:

	/**
	* Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
	*/

	package akka.contrib.pattern

	import language.postfixOps
	import scala.concurrent.duration._
	import com.typesafe.config.ConfigFactory
	import akka.actor.Actor

	// simple example of the cake pattern

	// abstract DAO trait
	trait Repository[A, B]{
	// saves an entity, returns an ID
	def save(entity: A): B
	// more features..
	}

	trait RdbmsRepository extends Repository[MyUserCaseClass, Long]{