Services are where we put the business logic. We will look at reactive persistence in Chapter 6, Persistence with Slick. Right now, we don't have a database to persist information, so, for now, we will do an in-memory persistence.
First we will define the contract of our services. This is the Base API that we will use in the controllers. Let's take a look at the following trait in BaseService.scala:
package services
import java.util.concurrent.atomic.AtomicLong
import scala.collection.mutable.HashMap
trait BaseService[A] {
var inMemoryDB = new HashMap[Long,A]
var idCounter = new AtomicLong(0)
def insert(a:A):Long
def update(id:Long,a:A):Boolean
def remove(id:Long):Boolean
def findById(id:Long):Option[A]
def findAll():Option[List[A]]
}
In the preceding code, we have an in-memory mutable HashMap, which...