isFinite tells us whether we can cache it; maybe it's coming from a predicate that checks the size, or something.class Cache[K,V](isFinite: Boolean, build: K => V): private val cache: mutable.Map[K, V] = mutable.Map[K, V]() private val app: K => V = if (isFinite) (k: K) => cache.getOrElseUpdate(k, build(k)) else (k: K) => build(k) inline def apply(k: K): V = app(k)
trait TimeReader {
def currentTime: Long = System.currentTimeMillis
def flowOfTime = Iterator.iterate(currentTime){_ => currentTime}
def interval(n:Long) = {
flowOfTime.next // the first drop, may be stale
val end = flowOfTime.next + n
flowOfTime takeWhile (end >)
}
def interval(duration: Duration) = interval(duration.toMillis)
//...
currentTime
for {
value <- readFromSource
t <- interval(60 seconds)
} useThisValue(value)
e.g.
for {i <- 1 to 10; t <- interval(1 second) } {Thread.sleep(1); println(s"$i @$t") }