Package io.smallrye.faulttolerance.api

Enum RateLimitType

java.lang.Object

java.lang.Enum<RateLimitType>

io.smallrye.faulttolerance.api.RateLimitType

All Implemented Interfaces:

Serializable, Comparable<RateLimitType>

public enum RateLimitType
extends Enum<RateLimitType>

Type of the time window used for rate limiting.

See Also:

FIXED, ROLLING, SMOOTH

Enum Constant Summary

Enum Constants

Enum Constant	Description
FIXED	Divides time into non-overlapping intervals of given length (time windows) and enforces the invocation limit for each interval independently.
ROLLING	Enforces the limit continuously, instead of dividing time into independent windows.
SMOOTH	Calculates the maximum rate of invocations from given time window length and given limit and enforces a uniform distribution of invocations over time under the calculated rate.

Method Summary

Modifier and Type	Method	Description
static RateLimitType	valueOf(String name)	Returns the enum constant of this type with the specified name.
static RateLimitType[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

FIXED

public static final RateLimitType FIXED

Divides time into non-overlapping intervals of given length (time windows) and enforces the invocation limit for each interval independently. This means that short bursts of invocations occuring near the time window boundaries may temporarily exceed the configured rate limit.

This is also called fixed window rate limiting.

Requires constant memory and time.

ROLLING

public static final RateLimitType ROLLING

Enforces the limit continuously, instead of dividing time into independent windows. The invocation limit is enforced for all possible time intervals of given length, regardless of overlap.

This is also called sliding log rate limiting.

Requires memory and time proportional to the maximum number of invocations in the time window, due to the need to store and check timestamps of recent invocations.

SMOOTH

public static final RateLimitType SMOOTH

Calculates the maximum rate of invocations from given time window length and given limit and enforces a uniform distribution of invocations over time under the calculated rate. If recent rate of invocations is under the limit, a subsequent burst of invocations is allowed during a shorter time span, but the calculated rate is never exceeded.

This is also called token bucket or leaky bucket (as a meter) rate limiting, with the additional property that all work units are considered to have the same size.

Requires constant memory and time.

Method Detail

values

public static RateLimitType[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (RateLimitType c : RateLimitType.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static RateLimitType valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null