Class SemaphoreBulkhead

java.lang.Object

io.github.resilience4j.bulkhead.internal.SemaphoreBulkhead

All Implemented Interfaces:

Bulkhead

public class SemaphoreBulkhead
extends Object
implements Bulkhead

A Bulkhead implementation based on a semaphore.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private class	SemaphoreBulkhead.BulkheadEventProcessor
private final class	SemaphoreBulkhead.BulkheadMetrics

Nested classes/interfaces inherited from interface Bulkhead

Bulkhead.BulkheadFuture<T>, Bulkhead.EventPublisher, Bulkhead.Metrics

Field Summary

Fields

Modifier and Type	Field	Description
private BulkheadConfig	config
private static final String	CONFIG_MUST_NOT_BE_NULL
private final Object	configChangesLock
private final SemaphoreBulkhead.BulkheadEventProcessor	eventProcessor
private final SemaphoreBulkhead.BulkheadMetrics	metrics
private final String	name
private final Semaphore	semaphore
private final Map<String,String>	tags
private static final String	TAGS_MUST_NOTE_BE_NULL

Constructor Summary

Constructors

Constructor	Description
SemaphoreBulkhead(String name)	Creates a bulkhead with a default config.
SemaphoreBulkhead(String name, BulkheadConfig bulkheadConfig)	Creates a bulkhead using a configuration supplied
SemaphoreBulkhead(String name, BulkheadConfig bulkheadConfig, Map<String,String> tags)	Creates a bulkhead using a configuration supplied
SemaphoreBulkhead(String name, Supplier<BulkheadConfig> configSupplier)	Create a bulkhead using a configuration supplier
SemaphoreBulkhead(String name, Supplier<BulkheadConfig> configSupplier, Map<String,String> tags)	Create a bulkhead using a configuration supplier

Method Summary

Modifier and Type	Method	Description
void	acquirePermission()	Acquires a permission to execute a call, only if one is available at the time of invocation If the current thread is interrupted while waiting for a permit then it won't throw InterruptedException, but its interrupt status will be set.
void	changeConfig(BulkheadConfig newConfig)	Dynamic bulkhead configuration change.
BulkheadConfig	getBulkheadConfig()	Returns the BulkheadConfig of this Bulkhead.
Bulkhead.EventPublisher	getEventPublisher()	Returns an EventPublisher which subscribes to the reactive stream of BulkheadEvent and can be used to register event consumers.
Bulkhead.Metrics	getMetrics()	Get the Metrics of this Bulkhead.
String	getName()	Returns the name of this bulkhead.
Map<String,String>	getTags()	Returns an unmodifiable map with tags assigned to this Bulkhead.
void	onComplete()	Records a completed call and releases a permission.
private void	publishBulkheadEvent(Supplier<BulkheadEvent> eventSupplier)
void	releasePermission()	Releases a permission and increases the number of available permits by one.
String	toString()
boolean	tryAcquirePermission()	Acquires a permission to execute a call, only if one is available at the time of invocation.
(package private) boolean	tryEnterBulkhead()

Methods inherited from class Object

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

Methods inherited from interface Bulkhead

executeCallable, executeCheckedSupplier, executeCompletionStage, executeRunnable, executeSupplier

Field Details

CONFIG_MUST_NOT_BE_NULL

private static final String CONFIG_MUST_NOT_BE_NULL

See Also:

• Constant Field Values

TAGS_MUST_NOTE_BE_NULL

private static final String TAGS_MUST_NOTE_BE_NULL

See Also:

• Constant Field Values

name

private final String name

semaphore

private final Semaphore semaphore

metrics

private final SemaphoreBulkhead.BulkheadMetrics metrics

eventProcessor

private final SemaphoreBulkhead.BulkheadEventProcessor eventProcessor

configChangesLock

private final Object configChangesLock

tags

private final Map<String,String> tags

config

private volatile BulkheadConfig config

Constructor Details

SemaphoreBulkhead

public SemaphoreBulkhead(String name,
 @Nullable
 BulkheadConfig bulkheadConfig)

Creates a bulkhead using a configuration supplied

Parameters:

name - the name of this bulkhead

bulkheadConfig - custom bulkhead configuration

SemaphoreBulkhead

public SemaphoreBulkhead(String name,
 @Nullable
 BulkheadConfig bulkheadConfig,
 Map<String,String> tags)

Creates a bulkhead using a configuration supplied

Parameters:

name - the name of this bulkhead

bulkheadConfig - custom bulkhead configuration

tags - the tags to add to the Bulkhead

SemaphoreBulkhead

public SemaphoreBulkhead(String name)

Creates a bulkhead with a default config.

Parameters:

name - the name of this bulkhead

SemaphoreBulkhead

public SemaphoreBulkhead(String name,
 Supplier<BulkheadConfig> configSupplier)

Create a bulkhead using a configuration supplier

Parameters:

name - the name of this bulkhead

configSupplier - BulkheadConfig supplier

SemaphoreBulkhead

public SemaphoreBulkhead(String name,
 Supplier<BulkheadConfig> configSupplier,
 Map<String,String> tags)

Create a bulkhead using a configuration supplier

Parameters:

name - the name of this bulkhead

configSupplier - BulkheadConfig supplier

tags - tags to add to the Bulkhead

Method Details

changeConfig

public void changeConfig(BulkheadConfig newConfig)

Dynamic bulkhead configuration change. NOTE! New `maxWaitTime` duration won't affect threads that are currently waiting for permission.

Specified by:

changeConfig in interface Bulkhead

Parameters:

newConfig - new BulkheadConfig

tryAcquirePermission

public boolean tryAcquirePermission()

Acquires a permission to execute a call, only if one is available at the time of invocation. 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:

tryAcquirePermission in interface Bulkhead

Returns:

true if a permission was acquired and false otherwise

acquirePermission

public void acquirePermission()

Acquires a permission to execute a call, only if one is available at the time of invocation 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 Bulkhead

releasePermission

public void releasePermission()

Releases a permission and increases the number of available permits by one.

Should only be used when a permission was acquired but not used. Otherwise use Bulkhead.onComplete() to signal a completed call and release a permission.

Specified by:

releasePermission in interface Bulkhead

onComplete

public void onComplete()

Records a completed call and releases a permission.

Specified by:

onComplete in interface Bulkhead

getName

public String getName()

Returns the name of this bulkhead.

Specified by:

getName in interface Bulkhead

Returns:

the name of this bulkhead

getBulkheadConfig

public BulkheadConfig getBulkheadConfig()

Returns the BulkheadConfig of this Bulkhead.

Specified by:

getBulkheadConfig in interface Bulkhead

Returns:

bulkhead config

getMetrics

public Bulkhead.Metrics getMetrics()

Get the Metrics of this Bulkhead.

Specified by:

getMetrics in interface Bulkhead

Returns:

the Metrics of this Bulkhead

getTags

public Map<String,String> getTags()

Returns an unmodifiable map with tags assigned to this Bulkhead.

Specified by:

getTags in interface Bulkhead

Returns:

the tags assigned to this Retry in an unmodifiable map

getEventPublisher

public Bulkhead.EventPublisher getEventPublisher()

Returns an EventPublisher which subscribes to the reactive stream of BulkheadEvent and can be used to register event consumers.

Specified by:

getEventPublisher in interface Bulkhead

Returns:

an EventPublisher

toString

public String toString()

Overrides:

toString in class Object

tryEnterBulkhead

boolean tryEnterBulkhead()

Returns:

true if caller was able to wait for permission without Thread.interrupt()

publishBulkheadEvent

private void publishBulkheadEvent(Supplier<BulkheadEvent> eventSupplier)