Class InMemoryRateLimitPolicy

java.lang.Object

com.svenruppert.jsentinel.ratelimiting.InMemoryRateLimitPolicy

All Implemented Interfaces:

RateLimitPolicy

@ExperimentalJSentinelApi
public final class InMemoryRateLimitPolicy
extends Object
implements RateLimitPolicy

Default RateLimitPolicy backed by a RateLimitStore.

Sliding-window semantics: every tryAcquire counts the events recorded in the last window; if the count is below the configured limit a fresh event is recorded and RateLimitDecision.Allowed is returned; otherwise the request is refused with RateLimitDecision.Throttled and a RateLimitExceeded audit event is published.

The audit emit-side optionally derives a subjectId from the RateLimitKey.scope() when the scope begins with the "subject:" prefix — purely a convenience so audit consumers can pivot on subject without parsing the composite scope themselves. For other scopes the audit event's subjectId is empty.

Thread-safe via the underlying store.

For brute-force / password-guessing detection, use LoginAttemptPolicy instead — same shape but with progressive backoff and lockout semantics. This policy is for steady-state traffic shaping.

Constructor Summary

Constructors

Constructor	Description
InMemoryRateLimitPolicy(RateLimitStore store, JSentinelAuditService auditService, int limit, Duration window)
InMemoryRateLimitPolicy(RateLimitStore store, JSentinelAuditService auditService, int limit, Duration window, Clock clock)	Full constructor.

Method Summary

Modifier and Type	Method	Description
int	limit()
int	purgeOldEvents()	Convenience: purges every event older than now - window across all keys.
void	reset(RateLimitKey key)	Resets the per-key state — typically after a successful authentication that cancels the throttle.
RateLimitDecision	tryAcquire(RateLimitKey key)	Attempts to record one event under key against the policy's configured per-window limit.
Duration	window()

Methods inherited from class Object

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

Constructor Details

InMemoryRateLimitPolicy

public InMemoryRateLimitPolicy(RateLimitStore store,
 JSentinelAuditService auditService,
 int limit,
 Duration window)

Parameters:

store - non-null

auditService - non-null

limit - max events per window; strictly positive

window - sliding-window duration; non-null, strictly positive

InMemoryRateLimitPolicy

public InMemoryRateLimitPolicy(RateLimitStore store,
 JSentinelAuditService auditService,
 int limit,
 Duration window,
 Clock clock)

Full constructor.

Parameters:

store - non-null

auditService - non-null

limit - max events per window; strictly positive

window - sliding-window duration; non-null, strictly positive

clock - time source; non-null

Method Details

tryAcquire

public RateLimitDecision tryAcquire(RateLimitKey key)

Description copied from interface: RateLimitPolicy

Attempts to record one event under key against the policy's configured per-window limit. The default behaviour mirrors a leaky bucket: an admitted event is counted, a throttled event is not. Concrete implementations document their semantics.

Specified by:

tryAcquire in interface RateLimitPolicy

Parameters:

key - non-null key; the scope is the application's choice — IP, subject, endpoint, or composed

Returns:

admit / throttle decision, never null

reset

public void reset(RateLimitKey key)

Resets the per-key state — typically after a successful authentication that cancels the throttle.

Parameters:

key - non-null

purgeOldEvents

public int purgeOldEvents()

Convenience: purges every event older than now - window across all keys. Idempotent; safe to schedule.

Returns:

number of events removed

limit

public int limit()

Returns:

configured per-window limit

window

public Duration window()

Returns:

configured window duration