Package io.github.resilience4j.ratelimiter.internal

Class SemaphoreBasedRateLimiter

java.lang.Object

io.github.resilience4j.ratelimiter.internal.SemaphoreBasedRateLimiter

All Implemented Interfaces:

RateLimiter

public class SemaphoreBasedRateLimiter
extends java.lang.Object
implements RateLimiter

A RateLimiter implementation that consists of Semaphore and scheduler that will refresh permissions after each RateLimiterConfig.getLimitRefreshPeriod().

Nested Class Summary

Nested classes/interfaces inherited from interface io.github.resilience4j.ratelimiter.RateLimiter

RateLimiter.EventPublisher, RateLimiter.Metrics

Constructor Summary

Constructors

Constructor	Description
SemaphoreBasedRateLimiter(java.lang.String name, RateLimiterConfig rateLimiterConfig)	Creates a RateLimiter.
SemaphoreBasedRateLimiter(java.lang.String name, RateLimiterConfig rateLimiterConfig, io.vavr.collection.Map<java.lang.String,java.lang.String> tags)	Creates a RateLimiter.
SemaphoreBasedRateLimiter(java.lang.String name, RateLimiterConfig rateLimiterConfig, java.util.concurrent.ScheduledExecutorService scheduler)	Creates a RateLimiter.
SemaphoreBasedRateLimiter(java.lang.String name, RateLimiterConfig rateLimiterConfig, java.util.concurrent.ScheduledExecutorService scheduler, io.vavr.collection.Map<java.lang.String,java.lang.String> tags)	Creates a RateLimiter.

Method Summary

Modifier and Type	Method	Description
boolean	acquirePermission(int permits)	Acquires the given number of permits from this rate limiter, blocking until one is available, or the thread is interrupted.
void	changeLimitForPeriod(int limitForPeriod)	Dynamic rate limiter configuration change.
void	changeTimeoutDuration(java.time.Duration timeoutDuration)	Dynamic rate limiter configuration change.
RateLimiter.EventPublisher	getEventPublisher()	Returns an EventPublisher which can be used to register event consumers.
RateLimiter.Metrics	getMetrics()	Get the Metrics of this RateLimiter.
java.lang.String	getName()	Get the name of this RateLimiter
RateLimiterConfig	getRateLimiterConfig()	Get the RateLimiterConfig of this RateLimiter.
io.vavr.collection.Map<java.lang.String,java.lang.String>	getTags()	Returns an unmodifiable map with tags assigned to this RateLimiter.
long	reservePermission()	Reserving permissions is not supported in the semaphore based implementation.
long	reservePermission(int permits)	Reserves the given number permits from this rate limiter and returns nanoseconds you should wait for it.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.github.resilience4j.ratelimiter.RateLimiter

acquirePermission, executeCallable, executeCallable, executeCheckedSupplier, executeCheckedSupplier, executeCompletionStage, executeEitherSupplier, executeEitherSupplier, executeRunnable, executeRunnable, executeSupplier, executeSupplier, executeTrySupplier, executeTrySupplier

Constructor Detail

SemaphoreBasedRateLimiter

public SemaphoreBasedRateLimiter(java.lang.String name,
                                 RateLimiterConfig rateLimiterConfig)

Creates a RateLimiter.

Parameters:

name - the name of the RateLimiter

rateLimiterConfig - The RateLimiter configuration.

SemaphoreBasedRateLimiter

public SemaphoreBasedRateLimiter(java.lang.String name,
                                 RateLimiterConfig rateLimiterConfig,
                                 io.vavr.collection.Map<java.lang.String,java.lang.String> tags)

Creates a RateLimiter.

Parameters:

name - the name of the RateLimiter

rateLimiterConfig - The RateLimiter configuration.

tags - tags to assign to the RateLimiter

SemaphoreBasedRateLimiter

public SemaphoreBasedRateLimiter(java.lang.String name,
                                 RateLimiterConfig rateLimiterConfig,
                                 @Nullable
                                 java.util.concurrent.ScheduledExecutorService scheduler)

Creates a RateLimiter.

Parameters:

name - the name of the RateLimiter

rateLimiterConfig - The RateLimiter configuration.

scheduler - executor that will refresh permissions

SemaphoreBasedRateLimiter

public SemaphoreBasedRateLimiter(java.lang.String name,
                                 RateLimiterConfig rateLimiterConfig,
                                 @Nullable
                                 java.util.concurrent.ScheduledExecutorService scheduler,
                                 io.vavr.collection.Map<java.lang.String,java.lang.String> tags)

Creates a RateLimiter.

Parameters:

name - the name of the RateLimiter

rateLimiterConfig - The RateLimiter configuration.

scheduler - executor that will refresh permissions

tags - tags to assign to the RateLimiter

Method Detail

changeTimeoutDuration

public void changeTimeoutDuration(java.time.Duration timeoutDuration)

Dynamic rate limiter configuration change. This method allows to change timeout duration of current limiter. NOTE! New timeout duration won't affect threads that are currently waiting for permission.

Specified by:

changeTimeoutDuration in interface RateLimiter

Parameters:

timeoutDuration - new timeout duration

changeLimitForPeriod

public void changeLimitForPeriod(int limitForPeriod)

Dynamic rate limiter configuration change. This method allows to change count of permissions available during refresh period. NOTE! New limit won't affect current period permissions and will apply only from next one.

Specified by:

changeLimitForPeriod in interface RateLimiter

Parameters:

limitForPeriod - new permissions limit

acquirePermission

public boolean acquirePermission(int permits)

Acquires the given number of permits from this rate limiter, blocking until one is available, or the thread is interrupted. Maximum wait time is RateLimiterConfig.getTimeoutDuration()

If the current thread is interrupted while waiting for a permit then it won't throw InterruptedException, but its interrupt status will be set.

Specified by:

acquirePermission in interface RateLimiter

Parameters:

permits - number of permits - use for systems where 1 call != 1 permit

Returns:

true if a permit was acquired and false if waiting timeoutDuration elapsed before a permit was acquired

reservePermission

public long reservePermission()

Reserving permissions is not supported in the semaphore based implementation. Semaphores are totally blocking by it's nature. So this non-blocking API isn't supported. Use RateLimiter.acquirePermission()

Specified by:

reservePermission in interface RateLimiter

Returns:

long amount of nanoseconds you should wait for reserved permissions. if negative, it means you failed to reserve.

Throws:

java.lang.UnsupportedOperationException - always for this implementation

reservePermission

public long reservePermission(int permits)

Description copied from interface: RateLimiter

Reserves the given number permits from this rate limiter and returns nanoseconds you should wait for it. If returned long is negative, it means that you failed to reserve permission, possibly your RateLimiterConfig.getTimeoutDuration() is less then time to wait for permission.

Specified by:

reservePermission in interface RateLimiter

Parameters:

permits - number of permits - use for systems where 1 call != 1 permit

Returns:

long amount of nanoseconds you should wait for reserved permissions. if negative, it means you failed to reserve.

Throws:

java.lang.UnsupportedOperationException - always for this implementation

See Also:

reservePermission()

getName

public java.lang.String getName()

Get the name of this RateLimiter

Specified by:

getName in interface RateLimiter

Returns:

the name of this RateLimiter

getMetrics

public RateLimiter.Metrics getMetrics()

Get the Metrics of this RateLimiter.

Specified by:

getMetrics in interface RateLimiter

Returns:

the Metrics of this RateLimiter

getEventPublisher

public RateLimiter.EventPublisher getEventPublisher()

Description copied from interface: RateLimiter

Returns an EventPublisher which can be used to register event consumers.

Specified by:

getEventPublisher in interface RateLimiter

Returns:

an EventPublisher

getRateLimiterConfig

public RateLimiterConfig getRateLimiterConfig()

Get the RateLimiterConfig of this RateLimiter.

Specified by:

getRateLimiterConfig in interface RateLimiter

Returns:

the RateLimiterConfig of this RateLimiter

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getTags

public io.vavr.collection.Map<java.lang.String,java.lang.String> getTags()

Description copied from interface: RateLimiter

Returns an unmodifiable map with tags assigned to this RateLimiter.

Specified by:

getTags in interface RateLimiter

Returns:

the tags assigned to this Retry in an unmodifiable map