Scala cache using Guava. Simple example.

cache_example1.scala

import scalacache._
import guava._
import memoization._

import com.google.common.cache.CacheBuilder

import scala.concurrent.Future
import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.duration._

object TestApp extends App {

  val underlyingGuavaCache = CacheBuilder.newBuilder().maximumSize(10000L).build[String, Object]

  implicit val scalaCache = ScalaCache(GuavaCache(underlyingGuavaCache))

  val db = Map(1 -> "A", 2 -> "B", 3 -> "C")

  def queryDb(id: Int): String = {
    println(s"Getting id $id from db")
    db(id)
  }

  def getUser(id: Int): Future[String] = memoize(30 days) {
    Future {
      queryDb(id)
    }
  }
  
  getUser(1)
  Thread.sleep(100)
  getUser(1)
  Thread.sleep(100)
  getUser(1)
  Thread.sleep(100)
  getUser(2)
  Thread.sleep(100)
  getUser(2)
  Thread.sleep(100)
  getUser(2)
  Thread.sleep(100)

  //  Output - Only hits 'db' once
  //  Getting id 1 from db
  //  Getting id 2 from db

}