Package org.jivesoftware.util

Class TokenBucketRateLimiter

java.lang.Object
org.jivesoftware.util.TokenBucketRateLimiter
public final class TokenBucketRateLimiter extends Object
A thread-safe, synchronized token-bucket rate limiter with metrics. This class limits the rate of arbitrary events. It is not tied to any specific domain such as networking or connections.
Author:
Guus der Kinderen, guus@goodbytes.nl

  • Constructor Details

    • TokenBucketRateLimiter

      public TokenBucketRateLimiter(long permitsPerSecond, long maxBurst)
      Creates a new rate limiter.
      Parameters:
      permitsPerSecond - sustained rate of permits
      maxBurst - maximum number of permits that can accumulate

  • Method Details

    • unlimited

      public static TokenBucketRateLimiter unlimited()
      Generates a limiter that allows unlimited events.
      Returns:
      an unlimited rate limiter.

    • tryAcquire

      public boolean tryAcquire()
      Attempts to acquire a single permit.
      Returns:
      true if the event is allowed, false otherwise

    • getPermitsPerSecond

      public long getPermitsPerSecond()
      Returns the sustained rate of permits.
      Returns:
      permits per second

    • getMaxBurst

      public long getMaxBurst()
      Returns the maximum burst size.
      Returns:
      maximum number of permits that can accumulate

    • getAvailableTokens

      public long getAvailableTokens()
      Returns the currently available number of permits.
      Returns:
      available permits

    • getAcceptedEvents

      public long getAcceptedEvents()
      Returns the total number of events that were allowed by this rate limiter since creation.
      Returns:
      number of accepted events

    • getRejectedEvents

      public long getRejectedEvents()
      Returns the total number of events that were rejected by this rate limiter since creation.
      Returns:
      number of rejected events

    • getTotalEvents

      public long getTotalEvents()
      Returns the total number of events evaluated by this limiter. This is the sum of accepted and rejected events.
      Returns:
      total number of events

    • getAcceptanceRatio

      public double getAcceptanceRatio()
      Returns the ratio of accepted events to total events. A value of 1.0 indicates that no events have been rejected. If no events have been observed yet, this method returns 1.0.
      Returns:
      acceptance ratio in the range [0.0, 1.0]

    • getUptime

      public Duration getUptime()
      Returns the duration for which this rate limiter has been active. The returned duration is based on monotonic time and is not affected by system clock changes.
      Returns:
      uptime duration

    • getAverageAcceptedRatePerSecond

      public double getAverageAcceptedRatePerSecond()
      Returns the average rate at which events have been accepted since creation. This value represents a coarse-grained average and is intended for diagnostics and reporting only.
      Returns:
      average accepted events per second