Package com.apple.foundationdb.relational.util

Class TokenBucketSampler

java.lang.Object

com.apple.foundationdb.relational.util.TokenBucketSampler

All Implemented Interfaces:

Sampler

@API(EXPERIMENTAL)
public class TokenBucketSampler
extends Object
implements Sampler

A sampling engine which will pass a sample test according to a TokenBucket algorithm.

A Token-bucket algorithm allows a constant average throughput, but allows some burstiness by building up tokens over periods of idleness. For more information, see Wikipedia. You can control the burstiness by configuring the maximum number of tokens to allow in the sampler, and the average rate by adjusting the refresh interval. Note, however, that the refresh interval is typically sensitive to the clock used in computing the interval--the refresh interval typically cannot be smaller than the resolution of the system clock used.

Constructor Summary

Constructors

Constructor	Description
TokenBucketSampler(int maxTokens, long refreshIntervalNanos, Clock clock)
TokenBucketSampler(int maxTokens, long refreshInterval, TimeUnit refreshTime, Clock clock)

Method Summary

Modifier and Type	Method	Description
boolean	canSample()	Determine if a sample should be taken.

Methods inherited from class java.lang.Object

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

Constructor Details

TokenBucketSampler

public TokenBucketSampler(int maxTokens,
 long refreshInterval,
 TimeUnit refreshTime,
 Clock clock)

TokenBucketSampler

public TokenBucketSampler(int maxTokens,
 long refreshIntervalNanos,
 Clock clock)

Method Details

canSample

public boolean canSample()

Determine if a sample should be taken.

Specified by:

canSample in interface Sampler

Returns:

true if a sample can be taken, false if it should be discarded.