Package reactor.pool

Class DefaultPoolConfig<POOLABLE>

java.lang.Object

reactor.pool.DefaultPoolConfig<POOLABLE>

All Implemented Interfaces:

PoolConfig<POOLABLE>

public class DefaultPoolConfig<POOLABLE>
extends Object
implements PoolConfig<POOLABLE>

A default PoolConfig that can be extended to bear more configuration options with access to a copy constructor for the basic options.

Author:

Simon Baslé

Field Summary

Fields

Modifier and Type	Field	Description
protected final Scheduler	acquisitionScheduler
protected final AllocationStrategy	allocationStrategy
protected final Mono<POOLABLE>	allocator
protected final Clock	clock
protected final Function<POOLABLE,? extends Publisher<Void>>	destroyHandler
protected final Duration	evictInBackgroundInterval
protected final Scheduler	evictInBackgroundScheduler
protected final BiPredicate<POOLABLE,PooledRefMetadata>	evictionPredicate
protected final boolean	isIdleLRU
protected final Duration	maxLifeTime
protected final double	maxLifeTimeVariance
protected final int	maxPending
protected final PoolMetricsRecorder	metricsRecorder
protected final BiFunction<Runnable,Duration,Disposable>	pendingAcquireTimer
protected final Function<POOLABLE,? extends Publisher<Void>>	releaseHandler

Constructor Summary

Constructors

Modifier	Constructor	Description
	DefaultPoolConfig(Mono<POOLABLE> allocator, AllocationStrategy allocationStrategy, int maxPending, BiFunction<Runnable,Duration,Disposable> pendingAcquireTimer, Function<POOLABLE,? extends Publisher<Void>> releaseHandler, Function<POOLABLE,? extends Publisher<Void>> destroyHandler, BiPredicate<POOLABLE,PooledRefMetadata> evictionPredicate, Duration evictInBackgroundInterval, Scheduler evictInBackgroundScheduler, Scheduler acquisitionScheduler, PoolMetricsRecorder metricsRecorder, Clock clock, boolean isIdleLRU)
	DefaultPoolConfig(Mono<POOLABLE> allocator, AllocationStrategy allocationStrategy, int maxPending, BiFunction<Runnable,Duration,Disposable> pendingAcquireTimer, Function<POOLABLE,? extends Publisher<Void>> releaseHandler, Function<POOLABLE,? extends Publisher<Void>> destroyHandler, BiPredicate<POOLABLE,PooledRefMetadata> evictionPredicate, Duration evictInBackgroundInterval, Scheduler evictInBackgroundScheduler, Scheduler acquisitionScheduler, PoolMetricsRecorder metricsRecorder, Clock clock, boolean isIdleLRU, Duration maxLifeTime, double maxLifeTimeVariance)
protected	DefaultPoolConfig(PoolConfig<POOLABLE> toCopy)	Copy constructor for the benefit of specializations of PoolConfig.

Method Summary

Modifier and Type	Method	Description
Scheduler	acquisitionScheduler()	When set, Pool implementation MAY decide to use the Scheduler to publish resources in a more deterministic way: the publishing thread would then always be the same, independently of which thread called Pool.acquire() or PooledRef.release() or on which thread the PoolConfig.allocator() produced new resources.
AllocationStrategy	allocationStrategy()	AllocationStrategy defines a strategy / limit for the number of pooled object to allocate.
Mono<POOLABLE>	allocator()	The asynchronous factory that produces new resources, represented as a Mono.
Clock	clock()	The Clock to use to timestamp pool lifecycle events like allocation and eviction, which can influence eg.
Function<POOLABLE,? extends Publisher<Void>>	destroyHandler()	Defines a mechanism of resource destruction, cleaning up state and OS resources it could maintain (eg.
Duration	evictInBackgroundInterval()	If the pool is configured to perform regular eviction checks on the background, returns the Duration representing the interval at which such checks are made.
Scheduler	evictInBackgroundScheduler()	If the pool is configured to perform regular eviction checks on the background, returns the Scheduler on which these checks are made.
BiPredicate<POOLABLE,PooledRefMetadata>	evictionPredicate()	A BiPredicate that checks if a resource should be destroyed (true) or is still in a valid state for recycling.
Duration	maxLifeTime()	The maximum lifetime for pooled resources.
double	maxLifeTimeVariance()	A variance percentage (0–100) applied to PoolConfig.maxLifeTime() to introduce per-resource jitter.
int	maxPending()	The maximum number of pending borrowers to enqueue before failing fast.
PoolMetricsRecorder	metricsRecorder()	The PoolMetricsRecorder to use to collect instrumentation data of the Pool implementations.
BiFunction<Runnable,Duration,Disposable>	pendingAcquireTimer()	The function that defines how timeouts are scheduled when a Pool.acquire(Duration) call is made and the acquisition is pending.
Function<POOLABLE,? extends Publisher<Void>>	releaseHandler()	When a resource is released, defines a mechanism of resetting any lingering state of the resource in order for it to become usable again.
boolean	reuseIdleResourcesInLruOrder()	The order in which idle (aka available) resources should be used when the pool was under-utilized and a new Pool.acquire() is performed.

Methods inherited from class java.lang.Object

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

Methods inherited from interface reactor.pool.PoolConfig

generateMaxLifeTimeMs

Field Details

pendingAcquireTimer

protected final BiFunction<Runnable,Duration,Disposable> pendingAcquireTimer

allocator

protected final Mono<POOLABLE> allocator

allocationStrategy

protected final AllocationStrategy allocationStrategy

maxPending

protected final int maxPending

releaseHandler

protected final Function<POOLABLE,? extends Publisher<Void>> releaseHandler

destroyHandler

protected final Function<POOLABLE,? extends Publisher<Void>> destroyHandler

evictionPredicate

protected final BiPredicate<POOLABLE,PooledRefMetadata> evictionPredicate

evictInBackgroundInterval

protected final Duration evictInBackgroundInterval

evictInBackgroundScheduler

protected final Scheduler evictInBackgroundScheduler

acquisitionScheduler

protected final Scheduler acquisitionScheduler

metricsRecorder

protected final PoolMetricsRecorder metricsRecorder

clock

protected final Clock clock

isIdleLRU

protected final boolean isIdleLRU

maxLifeTime

protected final Duration maxLifeTime

maxLifeTimeVariance

protected final double maxLifeTimeVariance

Constructor Details

DefaultPoolConfig

public DefaultPoolConfig(Mono<POOLABLE> allocator,
 AllocationStrategy allocationStrategy,
 int maxPending,
 BiFunction<Runnable,Duration,Disposable> pendingAcquireTimer,
 Function<POOLABLE,? extends Publisher<Void>> releaseHandler,
 Function<POOLABLE,? extends Publisher<Void>> destroyHandler,
 BiPredicate<POOLABLE,PooledRefMetadata> evictionPredicate,
 Duration evictInBackgroundInterval,
 Scheduler evictInBackgroundScheduler,
 Scheduler acquisitionScheduler,
 PoolMetricsRecorder metricsRecorder,
 Clock clock,
 boolean isIdleLRU)

DefaultPoolConfig

public DefaultPoolConfig(Mono<POOLABLE> allocator,
 AllocationStrategy allocationStrategy,
 int maxPending,
 BiFunction<Runnable,Duration,Disposable> pendingAcquireTimer,
 Function<POOLABLE,? extends Publisher<Void>> releaseHandler,
 Function<POOLABLE,? extends Publisher<Void>> destroyHandler,
 BiPredicate<POOLABLE,PooledRefMetadata> evictionPredicate,
 Duration evictInBackgroundInterval,
 Scheduler evictInBackgroundScheduler,
 Scheduler acquisitionScheduler,
 PoolMetricsRecorder metricsRecorder,
 Clock clock,
 boolean isIdleLRU,
 Duration maxLifeTime,
 double maxLifeTimeVariance)

DefaultPoolConfig

protected DefaultPoolConfig(PoolConfig<POOLABLE> toCopy)

Copy constructor for the benefit of specializations of PoolConfig.

Parameters:

toCopy - the original PoolConfig to copy (only standard PoolConfig options are copied)

Method Details

allocator

public Mono<POOLABLE> allocator()

Description copied from interface: PoolConfig

The asynchronous factory that produces new resources, represented as a Mono.

Specified by:

allocator in interface PoolConfig<POOLABLE>

allocationStrategy

public AllocationStrategy allocationStrategy()

Description copied from interface: PoolConfig

AllocationStrategy defines a strategy / limit for the number of pooled object to allocate.

Specified by:

allocationStrategy in interface PoolConfig<POOLABLE>

maxPending

public int maxPending()

Description copied from interface: PoolConfig

The maximum number of pending borrowers to enqueue before failing fast. 0 will immediately fail any acquire when no idle resource is available and the pool cannot grow. Use a negative number to deactivate.

Specified by:

maxPending in interface PoolConfig<POOLABLE>

pendingAcquireTimer

public BiFunction<Runnable,Duration,Disposable> pendingAcquireTimer()

Description copied from interface: PoolConfig

The function that defines how timeouts are scheduled when a Pool.acquire(Duration) call is made and the acquisition is pending. i.e. there is no idle resource and no new resource can be created currently, so a timeout is scheduled using the returned function.

By default, the Schedulers.parallel() scheduler is used.

Specified by:

pendingAcquireTimer in interface PoolConfig<POOLABLE>

Returns:

the function to apply when scheduling timers for pending acquisitions

releaseHandler

public Function<POOLABLE,? extends Publisher<Void>> releaseHandler()

Description copied from interface: PoolConfig

When a resource is released, defines a mechanism of resetting any lingering state of the resource in order for it to become usable again. The PoolConfig.evictionPredicate() is applied AFTER this reset.

For example, a buffer could have a readerIndex and writerIndex that need to be flipped back to zero.

Specified by:

releaseHandler in interface PoolConfig<POOLABLE>

destroyHandler

public Function<POOLABLE,? extends Publisher<Void>> destroyHandler()

Description copied from interface: PoolConfig

Defines a mechanism of resource destruction, cleaning up state and OS resources it could maintain (eg. off-heap objects, file handles, socket connections, etc...).

For example, a database connection could need to cleanly sever the connection link by sending a message to the database.

Specified by:

destroyHandler in interface PoolConfig<POOLABLE>

evictionPredicate

public BiPredicate<POOLABLE,PooledRefMetadata> evictionPredicate()

Description copied from interface: PoolConfig

A BiPredicate that checks if a resource should be destroyed (true) or is still in a valid state for recycling. This is primarily applied when a resource is released, to check whether or not it can immediately be recycled, but could also be applied during an acquire attempt (detecting eg. idle resources) or by a background reaping process. Both the resource and some metrics about the resource's life within the pool are provided.

Specified by:

evictionPredicate in interface PoolConfig<POOLABLE>

evictInBackgroundInterval

public Duration evictInBackgroundInterval()

Description copied from interface: PoolConfig

If the pool is configured to perform regular eviction checks on the background, returns the Duration representing the interval at which such checks are made. Otherwise returns Duration.ZERO (the default).

Specified by:

evictInBackgroundInterval in interface PoolConfig<POOLABLE>

evictInBackgroundScheduler

public Scheduler evictInBackgroundScheduler()

Description copied from interface: PoolConfig

If the pool is configured to perform regular eviction checks on the background, returns the Scheduler on which these checks are made. Otherwise returns Schedulers.immediate() (the default).

Specified by:

evictInBackgroundScheduler in interface PoolConfig<POOLABLE>

acquisitionScheduler

public Scheduler acquisitionScheduler()

Description copied from interface: PoolConfig

When set, Pool implementation MAY decide to use the Scheduler to publish resources in a more deterministic way: the publishing thread would then always be the same, independently of which thread called Pool.acquire() or PooledRef.release() or on which thread the PoolConfig.allocator() produced new resources. Note that not all pool implementations are guaranteed to enforce this, as they might have their own thread publishing semantics.

Defaults to Schedulers.immediate(), which inhibits this behavior.

Specified by:

acquisitionScheduler in interface PoolConfig<POOLABLE>

metricsRecorder

public PoolMetricsRecorder metricsRecorder()

Description copied from interface: PoolConfig

The PoolMetricsRecorder to use to collect instrumentation data of the Pool implementations.

Specified by:

metricsRecorder in interface PoolConfig<POOLABLE>

clock

public Clock clock()

Description copied from interface: PoolConfig

The Clock to use to timestamp pool lifecycle events like allocation and eviction, which can influence eg. the PoolConfig.evictionPredicate().

Specified by:

clock in interface PoolConfig<POOLABLE>

reuseIdleResourcesInLruOrder

public boolean reuseIdleResourcesInLruOrder()

Description copied from interface: PoolConfig

The order in which idle (aka available) resources should be used when the pool was under-utilized and a new Pool.acquire() is performed. Returns true if LRU (Least-Recently Used, the resource that was released first is emitted) or false for MRU (Most-Recently Used, the resource that was released last is emitted).

Specified by:

reuseIdleResourcesInLruOrder in interface PoolConfig<POOLABLE>

Returns:

true for LRU, false for MRU

maxLifeTime

public Duration maxLifeTime()

Description copied from interface: PoolConfig

The maximum lifetime for pooled resources. Resources that have been alive for longer than this duration will be evicted on acquire, release, or during background eviction.

Duration.ZERO disables lifetime-based eviction (the default).

When configured, this is composed with the PoolConfig.evictionPredicate() using OR logic — a resource is evicted if either condition triggers.

Specified by:

maxLifeTime in interface PoolConfig<POOLABLE>

Returns:

the maximum lifetime for pooled resources, or Duration.ZERO if disabled

See Also:

• PoolConfig.maxLifeTimeVariance()

maxLifeTimeVariance

public double maxLifeTimeVariance()

Description copied from interface: PoolConfig

A variance percentage (0–100) applied to PoolConfig.maxLifeTime() to introduce per-resource jitter. Each resource's effective max lifetime will fall in the range [maxLifeTime * (1 - variance/100), maxLifeTime], spreading resource renewal over a window instead of a single point in time.

Only meaningful when PoolConfig.maxLifeTime() is configured (non-zero). Default is 0 (no variance — all resources expire at exactly PoolConfig.maxLifeTime()).

Specified by:

maxLifeTimeVariance in interface PoolConfig<POOLABLE>

Returns:

the variance percentage, between 0 and 100

See Also:

• PoolConfig.maxLifeTime()