Class SlidingWindowStatistics

java.lang.Object

org.j7m.middleware.metrics.SlidingWindowStatistics

public final class SlidingWindowStatistics
extends Object

Thread-safe bounded sliding-window statistics collector.

The collector stores only the most recent capacity events and aggregate counters. It is intended for runtime diagnostics and HP scoring, not durable accounting.

Constructor Summary

Constructors

Constructor	Description
SlidingWindowStatistics(int capacity)	Creates a bounded statistics window.
SlidingWindowStatistics(int capacity, Duration retentionDuration, LongSupplier clock)	Creates a bounded statistics window with time-based retention.
SlidingWindowStatistics(int capacity, Duration retentionDuration, LongSupplier clock, int maxCounters)	Creates a bounded statistics window with time and counter-cardinality limits.

Method Summary

Modifier and Type	Method	Description
void	add(String name, long delta)	Adds a delta to one named counter.
void	increment(String name)	Increments one named counter.
void	record(String key, long timestampMillis, long latencyNanos, boolean success, org.j7m.middleware.api.MiddlewareErrorCode errorCode)	Records one timed event.
StatisticsSnapshot	snapshot()	Returns a point-in-time immutable snapshot.
double	successRate()	Returns success rate for recent aggregate counters.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

SlidingWindowStatistics

public SlidingWindowStatistics(int capacity)

Creates a bounded statistics window.

Parameters:

capacity - maximum retained events

SlidingWindowStatistics

public SlidingWindowStatistics(int capacity,
 Duration retentionDuration,
 LongSupplier clock)

Creates a bounded statistics window with time-based retention.

The supplied clock is used only for stale-event eviction during snapshot() and successRate(). Recorded event timestamps remain caller supplied so deterministic runtimes and tests can use an injected clock without relying on wall-clock time.

Parameters:

capacity - maximum retained events

retentionDuration - maximum age of retained events; non-positive values retain events for at least one millisecond

clock - clock returning the current wall-clock timestamp in milliseconds

SlidingWindowStatistics

public SlidingWindowStatistics(int capacity,
 Duration retentionDuration,
 LongSupplier clock,
 int maxCounters)

Creates a bounded statistics window with time and counter-cardinality limits.

Parameters:

capacity - maximum retained events

retentionDuration - maximum age of retained events; non-positive values retain events for at least one millisecond

clock - clock returning the current wall-clock timestamp in milliseconds

maxCounters - maximum named counters retained by this collector

Method Details

record

public void record(String key,
 long timestampMillis,
 long latencyNanos,
 boolean success,
 org.j7m.middleware.api.MiddlewareErrorCode errorCode)

Records one timed event.

Parameters:

key - event key, such as service or object id

timestampMillis - event timestamp

latencyNanos - latency in nanoseconds

success - whether the event succeeded

errorCode - optional error code

increment

public void increment(String name)

Increments one named counter.

Parameters:

name - counter name

add

public void add(String name,
 long delta)

Adds a delta to one named counter.

Parameters:

name - counter name

delta - counter delta

snapshot

public StatisticsSnapshot snapshot()

Returns a point-in-time immutable snapshot.

Returns:

statistics snapshot

successRate

public double successRate()

Returns success rate for recent aggregate counters.

Returns:

success rate in 0.0..1.0