JarCastingmules 
Caches are tricky - Let Mules Haul its Weight.
Quickstart
To use mules in an existing SBT project with Scala 2.11 or a later version, add the following dependencies to your build.sbt depending on your needs:
libraryDependencies ++= Seq(
"io.chrisdavenport" %% "mules" % "<version>"
)
Then the import
import io.chrisdavenport.mules._
import cats.effect.IO
import scala.concurrent.duration._
import scala.concurrent.ExecutionContext.global
// And Our Timer
implicit val timer = IO.timer(global)
Now Lets Use What We have built.
val getInserted = for {
cache <- MemoryCache.createMemoryCache[IO, String, Int](Some(Cache.TimeSpec.unsafeFromDuration(1.second)))
_ <- cache.insert("Foo", 1)
value <- cache.lookup("Foo")
} yield value
// getInserted: IO[Option[Int]] = Bind(
// Map(
// Delay(cats.effect.concurrent.Ref$$$Lambda$2068/1761796799@56bca113),
// io.chrisdavenport.mules.Cache$$$Lambda$2069/1167171712@494e6dbb,
// 0
// ),
// ammonite.$sess.cmd7$$$Lambda$2070/1795982619@447d91ef
// )
getInserted.unsafeRunSync
// res0: Option[Int] = Some(1)
val getRemoved = for {
cache <- MemoryCache.createMemoryCache[IO, String, Int](None)
_ <- cache.insert("Foo", 1)
_ <- cache.delete("Foo")
value <- cache.lookup("Foo")
} yield value
// getRemoved: IO[Option[Int]] = Bind(
// Map(
// Delay(cats.effect.concurrent.Ref$$$Lambda$2068/1761796799@63702e4),
// io.chrisdavenport.mules.Cache$$$Lambda$2069/1167171712@4b0d7cb5,
// 0
// ),
// ammonite.$sess.cmd9$$$Lambda$2129/709004859@4c511912
// )
getRemoved.unsafeRunSync
// res1: Option[Int] = None
val getAfterPurged = for {
cache <- MemoryCache.createMemoryCache[IO, String, Int](Some(Cache.TimeSpec.unsafeFromDuration(1.second)))
_ <- cache.insert("Foo", 1)
_ <- timer.sleep(2.seconds)
_ <- cache.purgeExpired
value <- cache.lookupNoUpdate("Foo")
} yield value
// getAfterPurged: IO[Option[Int]] = Bind(
// Map(
// Delay(cats.effect.concurrent.Ref$$$Lambda$2068/1761796799@aa77fd0),
// io.chrisdavenport.mules.Cache$$$Lambda$2069/1167171712@5bd3f1b3,
// 0
// ),
// ammonite.$sess.cmd13$$$Lambda$2170/787270911@6ce2f787
// )
getAfterPurged.unsafeRunSync
// res2: Option[Int] = None
val lookupAfterInterval = for {
cache <- MemoryCache.createMemoryCache[IO, String, Int](Some(Cache.TimeSpec.unsafeFromDuration(1.second)))
_ <- cache.insert("Foo", 1)
_ <- timer.sleep(2.seconds)
value <- cache.lookup("Foo")
} yield value
// lookupAfterInterval: IO[Option[Int]] = Bind(
// Map(
// Delay(cats.effect.concurrent.Ref$$$Lambda$2068/1761796799@345fa41d),
// io.chrisdavenport.mules.Cache$$$Lambda$2069/1167171712@6e5e4c90,
// 0
// ),
// ammonite.$sess.cmd15$$$Lambda$2183/1918145875@76c6c15
// )
lookupAfterInterval.unsafeRunSync
// res3: Option[Int] = None