Packages

abstract class Semaphore[F[_]] extends AnyRef

A purely functional semaphore.

A semaphore has a non-negative number of permits available. Acquiring a permit decrements the current number of permits and releasing a permit increases the current number of permits. An acquire that occurs when there are no permits available results in semantic blocking until a permit becomes available.

Blocking acquires are cancelable if the semaphore is created with Semaphore.apply (and hence, with a Concurrent[F] instance). Blocking acquires are non-cancelable if the semaphore is created with Semaphore.async (and hence, with an Async[F] instance).

Source
Semaphore.scala
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Instance Constructors

  1. new Semaphore()

Abstract Value Members

  1. abstract def acquireN(n: Long): F[Unit]

    Acquires n permits.

    Acquires n permits.

    The returned effect semantically blocks until all requested permits are available. Note that acquires are statisfied in strict FIFO order, so given s: Semaphore[F] with 2 permits available, an acquireN(3) will always be satisfied before a later call to acquireN(1).

    n

    number of permits to acquire - must be >= 0

  2. abstract def available: F[Long]

    Returns the number of permits currently available.

    Returns the number of permits currently available. Always non-negative.

    May be out of date the instant after it is retrieved. Use tryAcquire or tryAcquireN if you wish to attempt an acquire, returning immediately if the current count is not high enough to satisfy the request.

  3. abstract def count: F[Long]

    Obtains a snapshot of the current count.

    Obtains a snapshot of the current count. May be negative.

    Like available when permits are available but returns the number of permits callers are waiting for when there are no permits available.

  4. abstract def releaseN(n: Long): F[Unit]

    Releases n permits, potentially unblocking up to n outstanding acquires.

    Releases n permits, potentially unblocking up to n outstanding acquires.

    n

    number of permits to release - must be >= 0

  5. abstract def tryAcquireN(n: Long): F[Boolean]

    Acquires n permits now and returns true, or returns false immediately.

    Acquires n permits now and returns true, or returns false immediately. Error if n < 0.

    n

    number of permits to acquire - must be >= 0

  6. abstract def withPermit[A](t: F[A]): F[A]

    Returns an effect that acquires a permit, runs the supplied effect, and then releases the permit.

Concrete Value Members

  1. final def !=(arg0: Any): Boolean
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  2. final def ##: Int
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  3. final def ==(arg0: Any): Boolean
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  4. def acquire: F[Unit]

    Acquires a single permit.

    Acquires a single permit. Alias for acquireN(1).

  5. final def asInstanceOf[T0]: T0
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  6. def clone(): AnyRef
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    protected[lang]
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    @throws(classOf[java.lang.CloneNotSupportedException]) @native() @HotSpotIntrinsicCandidate()
  7. final def eq(arg0: AnyRef): Boolean
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  8. def equals(arg0: AnyRef): Boolean
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  9. final def getClass(): Class[_ <: AnyRef]
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  10. def hashCode(): Int
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  11. def imapK[G[_]](f: ~>[F, G], g: ~>[G, F]): Semaphore[G]

    Modify the context F using natural isomorphism f with g.

  12. final def isInstanceOf[T0]: Boolean
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  13. final def ne(arg0: AnyRef): Boolean
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  14. final def notify(): Unit
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    @native() @HotSpotIntrinsicCandidate()
  15. final def notifyAll(): Unit
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    @native() @HotSpotIntrinsicCandidate()
  16. def release: F[Unit]

    Releases a single permit.

    Releases a single permit. Alias for releaseN(1).

  17. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
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  18. def toString(): String
    Definition Classes
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  19. def tryAcquire: F[Boolean]

    Alias for tryAcquireN(1).

  20. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
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    @throws(classOf[java.lang.InterruptedException])
  21. final def wait(arg0: Long): Unit
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    @throws(classOf[java.lang.InterruptedException]) @native()
  22. final def wait(): Unit
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    @throws(classOf[java.lang.InterruptedException])

Deprecated Value Members

  1. def finalize(): Unit
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    @throws(classOf[java.lang.Throwable]) @Deprecated
    Deprecated

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