final case class Pure[F[_], +A](a: A) extends Resource[F, A] with Product with Serializable
- Source
- Resource.scala
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Instance Constructors
- new Pure(a: A)
Value Members
- final def !=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- def !>[B](that: Resource[F, B])(implicit F: MonadCancel[F, Throwable]): Resource[F, B]
- Definition Classes
- Resource
- final def ##: Int
- Definition Classes
- AnyRef → Any
- final def ==(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- val a: A
- def allocated[B >: A](implicit F: MonadCancel[F, Throwable]): F[(B, F[Unit])]
Given a
Resource
, possibly built by composing multipleResource
s monadically, returns the acquired resource, as well as an action that runs all the finalizers for releasing it.Given a
Resource
, possibly built by composing multipleResource
s monadically, returns the acquired resource, as well as an action that runs all the finalizers for releasing it.If the outer
F
fails or is interrupted,allocated
guarantees that the finalizers will be called. However, if the outerF
succeeds, it's up to the user to ensure the returnedF[Unit]
is called onceA
needs to be released. If the returnedF[Unit]
is not called, the finalizers will not be run.For this reason, this is an advanced and potentially unsafe api which can cause a resource leak if not used correctly, please prefer use as the standard way of running a
Resource
program.Use cases include interacting with side-effectful apis that expect separate acquire and release actions (like the
before
andafter
methods of many test frameworks), or complex library code that needs to modify or move the finalizer for an existing resource.- Definition Classes
- Resource
- def allocatedCase[B >: A](implicit F: MonadCancel[F, Throwable]): F[(B, (ExitCase) => F[Unit])]
Given a
Resource
, possibly built by composing multipleResource
s monadically, returns the acquired resource, as well as a cleanup function that takes an exit case and runs all the finalizers for releasing it.Given a
Resource
, possibly built by composing multipleResource
s monadically, returns the acquired resource, as well as a cleanup function that takes an exit case and runs all the finalizers for releasing it.If the outer
F
fails or is interrupted,allocated
guarantees that the finalizers will be called. However, if the outerF
succeeds, it's up to the user to ensure the returnedExitCode => F[Unit]
is called onceA
needs to be released. If the returnedExitCode => F[Unit]
is not called, the finalizers will not be run.For this reason, this is an advanced and potentially unsafe api which can cause a resource leak if not used correctly, please prefer use as the standard way of running a
Resource
program.Use cases include interacting with side-effectful apis that expect separate acquire and release actions (like the
before
andafter
methods of many test frameworks), or complex library code that needs to modify or move the finalizer for an existing resource.- Definition Classes
- Resource
- final def asInstanceOf[T0]: T0
- Definition Classes
- Any
- def attempt[E](implicit F: ApplicativeError[F, E]): Resource[F, Either[E, A]]
- Definition Classes
- Resource
- def both[B](that: Resource[F, B])(implicit F: Concurrent[F]): Resource[F, (A, B)]
Allocates two resources concurrently, and combines their results in a tuple.
Allocates two resources concurrently, and combines their results in a tuple.
The finalizers for the two resources are also run concurrently with each other, but within _each_ of the two resources, nested finalizers are run in the usual reverse order of acquisition.
The same Resource.ExitCase is propagated to every finalizer. If both resources acquired successfully, the Resource.ExitCase is determined by the outcome of use. Otherwise, it is determined by which resource failed or canceled first during acquisition.
Note that
Resource
also comes with acats.Parallel
instance that offers more convenient access to the same functionality asboth
, for example viaparMapN
:import scala.concurrent.duration._ import cats.effect.{IO, Resource} import cats.effect.std.Random import cats.syntax.all._ def mkResource(name: String) = { val acquire = for { n <- Random.scalaUtilRandom[IO].flatMap(_.nextIntBounded(1000)) _ <- IO.sleep(n.millis) _ <- IO.println(s"Acquiring $$name") } yield name def release(name: String) = IO.println(s"Releasing $$name") Resource.make(acquire)(release) } val r = (mkResource("one"), mkResource("two")) .parMapN((s1, s2) => s"I have $s1 and $s2") .use(IO.println(_))
- Definition Classes
- Resource
- def clone(): AnyRef
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.CloneNotSupportedException]) @native()
- def combine[B >: A](that: Resource[F, B])(implicit A: Semigroup[B]): Resource[F, B]
- Definition Classes
- Resource
- def combineK[B >: A](that: Resource[F, B])(implicit F: MonadCancel[F, Throwable], K: SemigroupK[F], G: Make[F]): Resource[F, B]
- Definition Classes
- Resource
- final def eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def evalMap[B](f: (A) => F[B]): Resource[F, B]
Applies an effectful transformation to the allocated resource.
Applies an effectful transformation to the allocated resource. Like a
flatMap
onF[A]
while maintaining the resource context- Definition Classes
- Resource
- def evalOn(ec: ExecutionContext)(implicit F: Async[F]): Resource[F, A]
- Definition Classes
- Resource
- def evalTap[B](f: (A) => F[B]): Resource[F, A]
Applies an effectful transformation to the allocated resource.
Applies an effectful transformation to the allocated resource. Like a
flatTap
onF[A]
while maintaining the resource context- Definition Classes
- Resource
- def finalize(): Unit
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable])
- def flatMap[B](f: (A) => Resource[F, B]): Resource[F, B]
Implementation for the
flatMap
operation, as described via thecats.Monad
type class.Implementation for the
flatMap
operation, as described via thecats.Monad
type class.- Definition Classes
- Resource
- def forceR[B](that: Resource[F, B])(implicit F: MonadCancel[F, Throwable]): Resource[F, B]
- Definition Classes
- Resource
- final def getClass(): Class[_ <: AnyRef]
- Definition Classes
- AnyRef → Any
- Annotations
- @native()
- def guaranteeCase(fin: (Outcome[[β$2$]Resource[F, β$2$], Throwable, A]) => Resource[F, Unit])(implicit F: MonadCancel[F, Throwable]): Resource[F, A]
- Definition Classes
- Resource
- def handleErrorWith[B >: A, E](f: (E) => Resource[F, B])(implicit F: ApplicativeError[F, E]): Resource[F, B]
- Definition Classes
- Resource
- final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- def map[B](f: (A) => B): Resource[F, B]
Given a mapping function, transforms the resource provided by this Resource.
Given a mapping function, transforms the resource provided by this Resource.
This is the standard
Functor.map
.- Definition Classes
- Resource
- def mapK[G[_]](f: ~>[F, G])(implicit F: MonadCancel[F, _], G: MonadCancel[G, _]): Resource[G, A]
Given a natural transformation from
F
toG
, transforms this Resource from effectF
to effectG
.Given a natural transformation from
F
toG
, transforms this Resource from effectF
to effectG
. The F and G constraint can also be satisfied by requiring a MonadCancelThrow[F] and MonadCancelThrow[G].- Definition Classes
- Resource
- final def ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- final def notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native()
- final def notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native()
- def onCancel(fin: Resource[F, Unit])(implicit F: MonadCancel[F, Throwable]): Resource[F, A]
- Definition Classes
- Resource
- def onFinalize(finalizer: F[Unit])(implicit F: Applicative[F]): Resource[F, A]
Runs
finalizer
when this resource is closed.Runs
finalizer
when this resource is closed. Unlike the release action passed toResource.make
, this will run even if resource acquisition fails or is canceled.- Definition Classes
- Resource
- def onFinalizeCase(f: (ExitCase) => F[Unit])(implicit F: Applicative[F]): Resource[F, A]
Like
onFinalize
, but the action performed depends on the exit case.Like
onFinalize
, but the action performed depends on the exit case.- Definition Classes
- Resource
- def preAllocate(precede: F[Unit]): Resource[F, A]
Runs
precede
before this resource is allocated.Runs
precede
before this resource is allocated.- Definition Classes
- Resource
- def productElementNames: Iterator[String]
- Definition Classes
- Product
- def race[B](that: Resource[F, B])(implicit F: Concurrent[F]): Resource[F, Either[A, B]]
Races the evaluation of two resource allocations and returns the result of the winner, except in the case of cancelation.
Races the evaluation of two resource allocations and returns the result of the winner, except in the case of cancelation.
- Definition Classes
- Resource
- def start(implicit F: Concurrent[F]): Resource[F, Fiber[[β$3$]Resource[F, β$3$], Throwable, A]]
- Definition Classes
- Resource
- def surround[B](gb: F[B])(implicit F: MonadCancel[F, Throwable]): F[B]
Acquires the resource, runs
gb
and closes the resource oncegb
terminates, fails or gets interruptedAcquires the resource, runs
gb
and closes the resource oncegb
terminates, fails or gets interrupted- Definition Classes
- Resource
- def surroundK(implicit F: MonadCancel[F, Throwable]): ~>[F, F]
Creates a FunctionK that can run
gb
within a resource, which is then closed oncegb
terminates, fails or gets interruptedCreates a FunctionK that can run
gb
within a resource, which is then closed oncegb
terminates, fails or gets interrupted- Definition Classes
- Resource
- final def synchronized[T0](arg0: => T0): T0
- Definition Classes
- AnyRef
- def use[B](f: (A) => F[B])(implicit F: MonadCancel[F, Throwable]): F[B]
Allocates a resource and supplies it to the given function.
Allocates a resource and supplies it to the given function. The resource is released as soon as the resulting
F[B]
is completed, whether normally or as a raised error.- f
the function to apply to the allocated resource
- returns
the result of applying [F] to
- Definition Classes
- Resource
- def useEval[B](implicit ev: <:<[A, F[B]], F: MonadCancel[F, Throwable]): F[B]
For a resource that allocates an action (type
F[B]
), allocate that action, run it and release it.For a resource that allocates an action (type
F[B]
), allocate that action, run it and release it.- Definition Classes
- Resource
- def useForever(implicit F: Spawn[F]): F[Nothing]
Allocates a resource with a non-terminating use action.
Allocates a resource with a non-terminating use action. Useful to run programs that are expressed entirely in
Resource
.The finalisers run when the resulting program fails or gets interrupted.
- Definition Classes
- Resource
- def useKleisli[B >: A, C](usage: Kleisli[F, B, C])(implicit F: MonadCancel[F, Throwable]): F[C]
Allocates the resource and uses it to run the given Kleisli.
Allocates the resource and uses it to run the given Kleisli.
- Definition Classes
- Resource
- def useKleisliK[B >: A](implicit F: MonadCancel[F, Throwable]): ~>[[γ$0$]Kleisli[F, B, γ$0$], F]
Creates a FunctionK that, when applied, will allocate the resource and use it to run the given Kleisli.
Creates a FunctionK that, when applied, will allocate the resource and use it to run the given Kleisli.
- Definition Classes
- Resource
- def use_(implicit F: MonadCancel[F, Throwable]): F[Unit]
Allocates a resource and closes it immediately.
Allocates a resource and closes it immediately.
- Definition Classes
- Resource
- final def wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException]) @native()