Package io.github.resilience4j.circuitbreaker.internal

Class CircuitBreakerStateMachine

java.lang.Object

io.github.resilience4j.circuitbreaker.internal.CircuitBreakerStateMachine

All Implemented Interfaces:

CircuitBreaker

public final class CircuitBreakerStateMachine
extends java.lang.Object
implements CircuitBreaker

A CircuitBreaker finite state machine.

Nested Class Summary

Nested classes/interfaces inherited from interface io.github.resilience4j.circuitbreaker.CircuitBreaker

CircuitBreaker.CircuitBreakerFuture<T>, CircuitBreaker.EventPublisher, CircuitBreaker.Metrics, CircuitBreaker.State, CircuitBreaker.StateTransition

Constructor Summary

Constructors

Constructor	Description
CircuitBreakerStateMachine(java.lang.String name)	Creates a circuitBreaker with default config.
CircuitBreakerStateMachine(java.lang.String name, CircuitBreakerConfig circuitBreakerConfig)	Creates a circuitBreaker.
CircuitBreakerStateMachine(java.lang.String name, CircuitBreakerConfig circuitBreakerConfig, SchedulerFactory schedulerFactory)	Creates a circuitBreaker.
CircuitBreakerStateMachine(java.lang.String name, CircuitBreakerConfig circuitBreakerConfig, io.vavr.collection.Map<java.lang.String,java.lang.String> tags)	Creates a circuitBreaker.
CircuitBreakerStateMachine(java.lang.String name, CircuitBreakerConfig circuitBreakerConfig, java.time.Clock clock)	Creates a circuitBreaker.
CircuitBreakerStateMachine(java.lang.String name, CircuitBreakerConfig circuitBreakerConfig, java.time.Clock clock, io.vavr.collection.Map<java.lang.String,java.lang.String> tags)	Creates a circuitBreaker.
CircuitBreakerStateMachine(java.lang.String name, java.util.function.Supplier<CircuitBreakerConfig> circuitBreakerConfig)	Creates a circuitBreaker.
CircuitBreakerStateMachine(java.lang.String name, java.util.function.Supplier<CircuitBreakerConfig> circuitBreakerConfig, io.vavr.collection.Map<java.lang.String,java.lang.String> tags)	Creates a circuitBreaker.

Method Summary

Modifier and Type	Method	Description
void	acquirePermission()	Try to obtain a permission to execute a call.
CircuitBreakerConfig	getCircuitBreakerConfig()	Get the config of this CircuitBreaker.
long	getCurrentTimestamp()	Returns the current time with respect to the CircuitBreaker currentTimeFunction.
CircuitBreaker.EventPublisher	getEventPublisher()	Returns an EventPublisher which can be used to register event consumers.
CircuitBreaker.Metrics	getMetrics()	Returns the Metrics of this CircuitBreaker.
java.lang.String	getName()	Get the name of this CircuitBreaker.
CircuitBreaker.State	getState()	Get the state of this CircuitBreaker.
io.vavr.collection.Map<java.lang.String,java.lang.String>	getTags()	Returns an unmodifiable map with tags assigned to this Retry.
java.util.concurrent.TimeUnit	getTimestampUnit()	Returns the timeUnit of current timestamp.
void	onError(long duration, java.util.concurrent.TimeUnit durationUnit, java.lang.Throwable throwable)	Records a failed call.
void	onResult(long duration, java.util.concurrent.TimeUnit durationUnit, java.lang.Object result)	This method must be invoked when a call returned a result and the result predicate should decide if the call was successful or not.
void	onSuccess(long duration, java.util.concurrent.TimeUnit durationUnit)	Records a successful call.
void	releasePermission()	Releases a permission.
void	reset()	Returns the circuit breaker to its original closed state, losing statistics.
java.lang.String	toString()
void	transitionToClosedState()	Transitions the state machine to CLOSED state.
void	transitionToDisabledState()	Transitions the state machine to a DISABLED state, stopping state transition, metrics and event publishing.
void	transitionToForcedOpenState()	Transitions the state machine to a FORCED_OPEN state, stopping state transition, metrics and event publishing.
void	transitionToHalfOpenState()	Transitions the state machine to HALF_OPEN state.
void	transitionToMetricsOnlyState()	Transitions the state machine to METRICS_ONLY state, stopping all state transitions but continues to capture metrics and publish events.
void	transitionToOpenState()	Transitions the state machine to OPEN state.
boolean	tryAcquirePermission()	Acquires a permission to execute a call, only if one is available at the time of invocation.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.github.resilience4j.circuitbreaker.CircuitBreaker

decorateCallable, decorateCheckedConsumer, decorateCheckedRunnable, decorateCheckedSupplier, decorateCompletionStage, decorateConsumer, decorateEitherSupplier, decorateFuture, decorateRunnable, decorateSupplier, decorateTrySupplier, executeCallable, executeCheckedRunnable, executeCheckedSupplier, executeCompletionStage, executeEitherSupplier, executeRunnable, executeSupplier, executeTrySupplier

Constructor Detail

CircuitBreakerStateMachine

public CircuitBreakerStateMachine(java.lang.String name,
                                  CircuitBreakerConfig circuitBreakerConfig,
                                  SchedulerFactory schedulerFactory)

Creates a circuitBreaker.

Parameters:

name - the name of the CircuitBreaker

circuitBreakerConfig - The CircuitBreaker configuration.

schedulerFactory - A SchedulerFactory which can be mocked in tests.

CircuitBreakerStateMachine

public CircuitBreakerStateMachine(java.lang.String name,
                                  CircuitBreakerConfig circuitBreakerConfig,
                                  java.time.Clock clock)

Creates a circuitBreaker.

Parameters:

name - the name of the CircuitBreaker

circuitBreakerConfig - The CircuitBreaker configuration.

CircuitBreakerStateMachine

public CircuitBreakerStateMachine(java.lang.String name,
                                  CircuitBreakerConfig circuitBreakerConfig,
                                  java.time.Clock clock,
                                  io.vavr.collection.Map<java.lang.String,java.lang.String> tags)

Creates a circuitBreaker.

Parameters:

name - the name of the CircuitBreaker

circuitBreakerConfig - The CircuitBreaker configuration.

CircuitBreakerStateMachine

public CircuitBreakerStateMachine(java.lang.String name,
                                  CircuitBreakerConfig circuitBreakerConfig)

Creates a circuitBreaker.

Parameters:

name - the name of the CircuitBreaker

circuitBreakerConfig - The CircuitBreaker configuration.

CircuitBreakerStateMachine

public CircuitBreakerStateMachine(java.lang.String name,
                                  CircuitBreakerConfig circuitBreakerConfig,
                                  io.vavr.collection.Map<java.lang.String,java.lang.String> tags)

Creates a circuitBreaker.

Parameters:

name - the name of the CircuitBreaker

circuitBreakerConfig - The CircuitBreaker configuration.

tags - Tags to add to the CircuitBreaker.

CircuitBreakerStateMachine

public CircuitBreakerStateMachine(java.lang.String name)

Creates a circuitBreaker with default config.

Parameters:

name - the name of the CircuitBreaker

CircuitBreakerStateMachine

public CircuitBreakerStateMachine(java.lang.String name,
                                  java.util.function.Supplier<CircuitBreakerConfig> circuitBreakerConfig)

Creates a circuitBreaker.

Parameters:

name - the name of the CircuitBreaker

circuitBreakerConfig - The CircuitBreaker configuration supplier.

CircuitBreakerStateMachine

public CircuitBreakerStateMachine(java.lang.String name,
                                  java.util.function.Supplier<CircuitBreakerConfig> circuitBreakerConfig,
                                  io.vavr.collection.Map<java.lang.String,java.lang.String> tags)

Creates a circuitBreaker.

Parameters:

name - the name of the CircuitBreaker

circuitBreakerConfig - The CircuitBreaker configuration supplier.

Method Detail

getCurrentTimestamp

public long getCurrentTimestamp()

Description copied from interface: CircuitBreaker

Returns the current time with respect to the CircuitBreaker currentTimeFunction. Returns System.nanoTime() by default.

Specified by:

getCurrentTimestamp in interface CircuitBreaker

Returns:

current timestamp

getTimestampUnit

public java.util.concurrent.TimeUnit getTimestampUnit()

Description copied from interface: CircuitBreaker

Returns the timeUnit of current timestamp. Default is TimeUnit.NANOSECONDS.

Specified by:

getTimestampUnit in interface CircuitBreaker

Returns:

the timeUnit of current timestamp

tryAcquirePermission

public boolean tryAcquirePermission()

Description copied from interface: CircuitBreaker

Acquires a permission to execute a call, only if one is available at the time of invocation. If a call is not permitted, the number of not permitted calls is increased.

Returns false when the state is OPEN or FORCED_OPEN. Returns true when the state is CLOSED or DISABLED. Returns true when the state is HALF_OPEN and further test calls are allowed. Returns false when the state is HALF_OPEN and the number of test calls has been reached. If the state is HALF_OPEN, the number of allowed test calls is decreased. Important: Make sure to call onSuccess or onError after the call is finished. If the call is cancelled before it is invoked, you have to release the permission again.

Specified by:

tryAcquirePermission in interface CircuitBreaker

Returns:

true if a permission was acquired and false otherwise

releasePermission

public void releasePermission()

Description copied from interface: CircuitBreaker

Releases a permission.

Should only be used when a permission was acquired but not used. Otherwise use CircuitBreaker.onSuccess(long, TimeUnit) or CircuitBreaker.onError(long, TimeUnit, Throwable) to signal a completed or failed call.

If the state is HALF_OPEN, the number of allowed test calls is increased by one.

Specified by:

releasePermission in interface CircuitBreaker

acquirePermission

public void acquirePermission()

Description copied from interface: CircuitBreaker

Try to obtain a permission to execute a call. If a call is not permitted, the number of not permitted calls is increased.

Throws a CallNotPermittedException when the state is OPEN or FORCED_OPEN. Returns when the state is CLOSED or DISABLED. Returns when the state is HALF_OPEN and further test calls are allowed. Throws a CallNotPermittedException when the state is HALF_OPEN and the number of test calls has been reached. If the state is HALF_OPEN, the number of allowed test calls is decreased. Important: Make sure to call onSuccess or onError after the call is finished. If the call is cancelled before it is invoked, you have to release the permission again.

Specified by:

acquirePermission in interface CircuitBreaker

onError

public void onError(long duration,
                    java.util.concurrent.TimeUnit durationUnit,
                    java.lang.Throwable throwable)

Description copied from interface: CircuitBreaker

Records a failed call. This method must be invoked when a call failed.

Specified by:

onError in interface CircuitBreaker

Parameters:

duration - The elapsed time duration of the call

durationUnit - The duration unit

throwable - The throwable which must be recorded

onSuccess

public void onSuccess(long duration,
                      java.util.concurrent.TimeUnit durationUnit)

Description copied from interface: CircuitBreaker

Records a successful call. This method must be invoked when a call was successful.

Specified by:

onSuccess in interface CircuitBreaker

Parameters:

duration - The elapsed time duration of the call

durationUnit - The duration unit

onResult

public void onResult(long duration,
                     java.util.concurrent.TimeUnit durationUnit,
                     @Nullable
                     java.lang.Object result)

Description copied from interface: CircuitBreaker

This method must be invoked when a call returned a result and the result predicate should decide if the call was successful or not.

Specified by:

onResult in interface CircuitBreaker

Parameters:

duration - The elapsed time duration of the call

durationUnit - The duration unit

result - The result of the protected function

getState

public CircuitBreaker.State getState()

Get the state of this CircuitBreaker.

Specified by:

getState in interface CircuitBreaker

Returns:

the the state of this CircuitBreaker

getName

public java.lang.String getName()

Get the name of this CircuitBreaker.

Specified by:

getName in interface CircuitBreaker

Returns:

the the name of this CircuitBreaker

getCircuitBreakerConfig

public CircuitBreakerConfig getCircuitBreakerConfig()

Get the config of this CircuitBreaker.

Specified by:

getCircuitBreakerConfig in interface CircuitBreaker

Returns:

the config of this CircuitBreaker

getMetrics

public CircuitBreaker.Metrics getMetrics()

Description copied from interface: CircuitBreaker

Returns the Metrics of this CircuitBreaker.

Specified by:

getMetrics in interface CircuitBreaker

Returns:

the Metrics of this CircuitBreaker

getTags

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

Description copied from interface: CircuitBreaker

Returns an unmodifiable map with tags assigned to this Retry.

Specified by:

getTags in interface CircuitBreaker

Returns:

the tags assigned to this Retry in an unmodifiable map

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

reset

public void reset()

Description copied from interface: CircuitBreaker

Returns the circuit breaker to its original closed state, losing statistics.

Should only be used, when you want to want to fully reset the circuit breaker without creating a new one.

Specified by:

reset in interface CircuitBreaker

transitionToDisabledState

public void transitionToDisabledState()

Description copied from interface: CircuitBreaker

Transitions the state machine to a DISABLED state, stopping state transition, metrics and event publishing. This call is idempotent and will not have any effect if the state machine is already in DISABLED state.

Should only be used, when you want to disable the circuit breaker allowing all calls to pass. To recover from this state you must force a new state transition

Specified by:

transitionToDisabledState in interface CircuitBreaker

transitionToMetricsOnlyState

public void transitionToMetricsOnlyState()

Description copied from interface: CircuitBreaker

Transitions the state machine to METRICS_ONLY state, stopping all state transitions but continues to capture metrics and publish events. This call is idempotent and will not have any effect if the state machine is already in METRICS_ONLY state.

Should only be used when you want to collect metrics while keeping the circuit breaker disabled, allowing all calls to pass. To recover from this state you must force a new state transition.

Specified by:

transitionToMetricsOnlyState in interface CircuitBreaker

transitionToForcedOpenState

public void transitionToForcedOpenState()

Description copied from interface: CircuitBreaker

Transitions the state machine to a FORCED_OPEN state, stopping state transition, metrics and event publishing. This call is idempotent and will not have any effect if the state machine is already in FORCED_OPEN state.

Should only be used, when you want to disable the circuit breaker allowing no call to pass. To recover from this state you must force a new state transition

Specified by:

transitionToForcedOpenState in interface CircuitBreaker

transitionToClosedState

public void transitionToClosedState()

Description copied from interface: CircuitBreaker

Transitions the state machine to CLOSED state. This call is idempotent and will not have any effect if the state machine is already in CLOSED state.

Should only be used, when you want to force a state transition. State transition are normally done internally.

Specified by:

transitionToClosedState in interface CircuitBreaker

transitionToOpenState

public void transitionToOpenState()

Description copied from interface: CircuitBreaker

Transitions the state machine to OPEN state. This call is idempotent and will not have any effect if the state machine is already in OPEN state.

Should only be used, when you want to force a state transition. State transition are normally done internally.

Specified by:

transitionToOpenState in interface CircuitBreaker

transitionToHalfOpenState

public void transitionToHalfOpenState()

Description copied from interface: CircuitBreaker

Transitions the state machine to HALF_OPEN state. This call is idempotent and will not have any effect if the state machine is already in HALF_OPEN state.

Should only be used, when you want to force a state transition. State transition are normally done internally.

Specified by:

transitionToHalfOpenState in interface CircuitBreaker

getEventPublisher

public CircuitBreaker.EventPublisher getEventPublisher()

Description copied from interface: CircuitBreaker

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

Specified by:

getEventPublisher in interface CircuitBreaker

Returns:

an EventPublisher