kumulant/com.eignex.kumulant.schema/StatGroup

StatGroup

class StatGroup(stats: List<BoundStat<*, out SeriesStat<*>, *>>, concurrency: Concurrency? = null) : AbstractStatGroup<SeriesStat<*>> , SeriesStat<GroupResult> (source)

Fans each update out to a heterogeneous list of SeriesStats and reports their results keyed by name.

Constructors

StatGroup

constructor(stats: List<BoundStat<*, out SeriesStat<*>, *>>, concurrency: Concurrency? = null)

constructor(vararg stats: BoundStat<*, out SeriesStat<*>, *>, concurrency: Concurrency? = null)

constructor(vararg stats: Pair<StatKey<*>, SeriesStat<*>>, concurrency: Concurrency? = null)

constructor(schema: StatSchema, concurrency: Concurrency? = null)

Properties

concurrency

override val concurrency: Concurrency

The thread-safety contract this stat was constructed with. Each stat picks the cell-encoding and lock strategy that honours this contract for its mathematical structure:

Functions

create

open override fun create(concurrency: Concurrency? = null): SeriesStat<GroupResult>

Spawn a fresh accumulator with the same configuration. Optionally override the Concurrency; useful for materialising a wire spec at a different concurrency level than the source.

merge

override fun merge(values: GroupResult)

Fold another accumulator's snapshot into this one. The unit of merge is the immutable Result; not a live Stat; which is what lets the merge cross a process boundary. Many workers track slices of the same stream, call read periodically, ship snapshots to a coordinator, and the coordinator merges them in.

read

override fun read(timestampNanos: Long = currentTimeNanos()): GroupResult

Materialise the current state as an immutable Result. Reads never mutate, so the caller can read as often as it likes without affecting the stream.

reset

override fun reset()

Reset the stat to its prior-seeded baseline. Equivalent to constructing a fresh stat with the same configuration, but in place; keeps the same Concurrency and any per-stat tunables.

update

open fun update(value: Double, weight: Double = 1.0)

Record an observation with the given weight, stamped at the current time.

open override fun update(value: Double, timestampNanos: Long, weight: Double = 1.0)

Record an observation at timestampNanos with the given weight. Stats that consume time (rates, decay, windowing) use this as the ordering signal; pass a monotonic stamp when feeding from a replay log.

StatGroup

constructor(stats: List<BoundStat<*, out SeriesStat<*>, *>>, concurrency: Concurrency? = null)(source)

constructor(vararg stats: BoundStat<*, out SeriesStat<*>, *>, concurrency: Concurrency? = null)(source)

constructor(vararg stats: Pair<StatKey<*>, SeriesStat<*>>, concurrency: Concurrency? = null)(source)

constructor(schema: StatSchema, concurrency: Concurrency? = null)(source)

create

open override fun create(concurrency: Concurrency? = null): SeriesStat<GroupResult>(source)

Spawn a fresh accumulator with the same configuration. Optionally override the Concurrency; useful for materialising a wire spec at a different concurrency level than the source.

The returned stat is independent: its state starts at the configured baseline, not at the source's current state. Each modality subtype narrows the return type so chaining doesn't lose the modality.

update

open override fun update(value: Double, timestampNanos: Long, weight: Double = 1.0)(source)