Class FixedSizeSlidingWindowMetrics

  • All Implemented Interfaces:

    public class FixedSizeSlidingWindowMetrics
    extends java.lang.Object
    implements Metrics
    A Metrics implementation is backed by a sliding window that aggregates only the last N calls.

    The sliding window is implemented with a circular array of N measurements. If the time window size is 10, the circular array has always 10 measurements.

    The sliding window incrementally updates a total aggregation. The total aggregation is updated incrementally when a new call outcome is recorded. When the oldest measurement is evicted, the measurement is subtracted from the total aggregation. (Subtract-on-Evict)

    The time to retrieve a Snapshot is constant 0(1), since the Snapshot is pre-aggregated and is independent of the window size. The space requirement (memory consumption) of this implementation should be O(n).

    • Constructor Detail

      • FixedSizeSlidingWindowMetrics

        public FixedSizeSlidingWindowMetrics​(int windowSize)
        Creates a new FixedSizeSlidingWindowMetrics with the given window size.
        windowSize - the window size
    • Method Detail

      • record

        public Snapshot record​(long duration,
                               java.util.concurrent.TimeUnit durationUnit,
                               Metrics.Outcome outcome)
        Description copied from interface: Metrics
        Records a call.
        Specified by:
        record in interface Metrics
        duration - the duration of the call
        durationUnit - the time unit of the duration
        outcome - the outcome of the call
      • getSnapshot

        public Snapshot getSnapshot()
        Description copied from interface: Metrics
        Returns a snapshot.
        Specified by:
        getSnapshot in interface Metrics
        a snapshot