Reservoir that resets on Snapshot

ResetOnSnapshotReservoir.scala

import com.codahale.metrics.{UniformReservoir, Reservoir => CodaHaleReservoir}

/**
  *  A Reservoir [backed by a UniformReservoir] that resets its internal state on each snapshot.
  *  (which is how reporters get information from reservoirs).
  */
class ResetOnSnapshotReservoir extends CodaHaleReservoir {
  @volatile private var reservoir: CodaHaleReservoir = getNewReservoir

  override def update(value: Long) = reservoir.update(value)

  override def getSnapshot = {
    val reservoirCopy = reservoir
    reservoir = getNewReservoir
    reservoirCopy.getSnapshot
  }

  override def size() = reservoir.size()

  private def getNewReservoir: CodaHaleReservoir = new UniformReservoir()
}