In memory ttl cache

Cache.scala

class InMemoryTTLCache[T <: AnyRef](settings: TTLCacheSettings, zeroFun: String => T) extends Cache[T] {
  val underlying = CacheBuilder.newBuilder()
    .initialCapacity(30)
    .expireAfterWrite(settings.maxAgeInSeconds, TimeUnit.SECONDS)
    .build[String, T](new CacheLoader[String, T] {
      override def load(key: String): T = zeroFun(key)
    })
  override def get(cacheKey: String): Option[T] = Option(underlying.get(cacheKey))
  override def set(cacheKey: String, value: T): Unit = underlying.put(cacheKey, value)
  override def delete(cacheKeys: Seq[String]): Unit = cacheKeys.foreach(underlying.invalidate)
}